Hiatal hernia uptake of iodine-131 mimicking mediastinal metastasis of papillary thyroid carcinoma.

PubMed

Haghighatafshar, Mahdi; Khajehrahimi, Farnaz

2015-01-01

There are a few case reports of hiatal hernia demonstrating thoracic uptake on I-131 scintigraphy. In this case, high thyroglobulin levels in combination with misinterpretation of I-131 uptake in the mediastinum, leaded to mismanagement of the patient. Here we present a case of focal I-131 uptake within a hiatal hernia initially mimicking an isolated mediastinal metastasis. There are many potential causes of false-positive I-131 scan result. In this case, adjunctive chest computed tomography and gastroesophageal barium study helped to elucidate the true nature of this I-131 uptake. False-positive findings may be caused by a wide variety of nonthyroidal carcinomas, which can concentrate radioiodine or from skin contamination. Several organs, such as the gastric, salivary glands, renal cyst, pericardial effusion, and ovarian can accumulate I-131. It should be borne in mind as a potential source of false-positive whole-body I-131 imaging.

Applying a CAD-generated imaging marker to assess short-term breast cancer risk

NASA Astrophysics Data System (ADS)

Mirniaharikandehei, Seyedehnafiseh; Zarafshani, Ali; Heidari, Morteza; Wang, Yunzhi; Aghaei, Faranak; Zheng, Bin

2018-02-01

Although whether using computer-aided detection (CAD) helps improve radiologists' performance in reading and interpreting mammograms is controversy due to higher false-positive detection rates, objective of this study is to investigate and test a new hypothesis that CAD-generated false-positives, in particular, the bilateral summation of false-positives, is a potential imaging marker associated with short-term breast cancer risk. An image dataset involving negative screening mammograms acquired from 1,044 women was retrospectively assembled. Each case involves 4 images of craniocaudal (CC) and mediolateral oblique (MLO) view of the left and right breasts. In the next subsequent mammography screening, 402 cases were positive for cancer detected and 642 remained negative. A CAD scheme was applied to process all "prior" negative mammograms. Some features from CAD scheme were extracted, which include detection seeds, the total number of false-positive regions, an average of detection scores and the sum of detection scores in CC and MLO view images. Then the features computed from two bilateral images of left and right breasts from either CC or MLO view were combined. In order to predict the likelihood of each testing case being positive in the next subsequent screening, two logistic regression models were trained and tested using a leave-one-case-out based cross-validation method. Data analysis demonstrated the maximum prediction accuracy with an area under a ROC curve of AUC=0.65+/-0.017 and the maximum adjusted odds ratio of 4.49 with a 95% confidence interval of [2.95, 6.83]. The results also illustrated an increasing trend in the adjusted odds ratio and risk prediction scores (p<0.01). Thus, the study showed that CAD-generated false-positives might provide a new quantitative imaging marker to help assess short-term breast cancer risk.

Imaging in gynaecology: How good are we in identifying endometriomas?

PubMed Central

Van Holsbeke, C.; Van Calster, B.; Guerriero, S.; Savelli, L.; Leone, F.; Fischerova, D; Czekierdowski, A.; Fruscio, R.; Veldman, J.; Van de Putte, G.; Testa, A.C.; Bourne, T.; Valentin, L.; Timmerman, D.

2009-01-01

Aim: To evaluate the performance of subjective evaluation of ultrasound findings (pattern recognition) to discriminate endometriomas from other types of adnexal masses and to compare the demographic and ultrasound characteristics of the true positive cases with those cases that were presumed to be an endometrioma but proved to have a different histology (false positive cases) and the endometriomas missed by pattern recognition (false negative cases). Methods: All patients in the International Ovarian Tumor Analysis (IOTA ) studies were included for analysis. In the IOTA studies, patients with an adnexal mass that were preoperatively examined by expert sonologists following the same standardized ultrasound protocol were prospectively included in 21 international centres. Sensitivity and specificity to discriminate endometriomas from other types of adnexal masses using pattern recognition were calculated. Ultrasound and some demographic variables of the masses presumed to be an endometrioma were analysed (true positives and false positives) and compared with the variables of the endometriomas missed by pattern recognition (false negatives) as well as the true negatives. Results: IOTA phase 1, 1b and 2 included 3511 patients of which 2560 were benign (73%) and 951 malignant (27%). The dataset included 713 endometriomas. Sensitivity and specificity for pattern recognition were 81% (577/713) and 97% (2723/2798). The true positives were more often unilocular with ground glass echogenicity than the masses in any other category. Among the 75 false positive cases, 66 were benign but 9 were malignant (5 borderline tumours, 1 rare primary invasive tumour and 3 endometrioid adenocarcinomas). The presumed diagnosis suggested by the sonologist in case of a missed endometrioma was mostly functional cyst or cystadenoma. Conclusion: Expert sonologists can quite accurately discriminate endometriomas from other types of adnexal masses, but in this dataset 1% of the masses that were classified as endometrioma by pattern recognition proved to be malignancies. PMID:25478066

Two cases of false-positive dengue non-structural protein 1 (NS1) antigen in patients with hematological malignancies and a review of the literature on the use of NS1 for the detection of Dengue infection.

PubMed

Chung, Shimin J; Krishnan, Prabha U; Leo, Yee Sin

2015-02-01

Early diagnosis of dengue has been made easier in recent years owing to the advancement in diagnostic technologies. The rapid non-structural protein 1 (NS1) test strip is widely used in many developed and developing regions at risk of dengue. Despite the relatively high specificity of this test, we recently encountered two cases of false-positive dengue NS1 antigen in patients with underlying hematological malignancies. We reviewed the literature for causes of false-positive dengue NS1. © The American Society of Tropical Medicine and Hygiene.

Can integrated 18F-FDG PET/MR replace sentinel lymph node resection in malignant melanoma?

PubMed

Schaarschmidt, Benedikt Michael; Grueneisen, Johannes; Stebner, Vanessa; Klode, Joachim; Stoffels, Ingo; Umutlu, Lale; Schadendorf, Dirk; Heusch, Philipp; Antoch, Gerald; Pöppel, Thorsten Dirk

2018-06-06

To compare the sensitivity and specificity of 18F-fluordesoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT), 18F-FDG PET/magnetic resonance (18F-FDG PET/MR) and 18F-FDG PET/MR including diffusion weighted imaging (DWI) in the detection of sentinel lymph node metastases in patients suffering from malignant melanoma. Fifty-two patients with malignant melanoma (female: n = 30, male: n = 22, mean age 50.5 ± 16.0 years, mean tumor thickness 2.28 ± 1.97 mm) who underwent 18F-FDG PET/CT and subsequent PET/MR & DWI for distant metastasis staging were included in this retrospective study. After hybrid imaging, lymphoscintigraphy including single photon emission computed tomography/CT (SPECT/CT) was performed to identify the sentinel lymph node prior to sentinel lymph node biopsy (SLNB). In a total of 87 sentinel lymph nodes in 64 lymph node basins visible on SPECT/CT, 17 lymph node metastases were detected by histopathology. In separate sessions PET/CT, PET/MR, and PET/MR & DWI were assessed for sentinel lymph node metastases by two independent readers. Discrepant results were resolved in a consensus reading. Sensitivities, specificities, positive predictive values and negative predictive values were calculated with histopathology following SPECT/CT guided SLNB as a reference standard. Compared with histopathology, lymph nodes were true positive in three cases, true negative in 65 cases, false positive in three cases and false negative in 14 cases in PET/CT. PET/MR was true positive in four cases, true negative in 63 cases, false positive in two cases and false negative in 13 cases. Hence, we observed a sensitivity, specificity, positive predictive value and negative predictive value of 17.7, 95.6, 50.0 and 82.3% for PET/CT and 23.5, 96.9, 66.7 and 82.3% for PET/MR. In DWI, 56 sentinel lymph node basins could be analyzed. Here, the additional analysis of DWI led to two additional false positive findings, while the number of true positive findings could not be increased. In conclusion, integrated 18F-FDG PET/MR does not reliably differentiate N-positive from N-negative melanoma patients. Additional DWI does not increase the sensitivity of 18F-FDG PET/MR. Hence, sentinel lymph node biopsy cannot be replaced by 18F-FDG-PE/MR or 18F-FDG-PET/CT.

Computer-aided diagnosis of contrast-enhanced spectral mammography: A feasibility study.

PubMed

Patel, Bhavika K; Ranjbar, Sara; Wu, Teresa; Pockaj, Barbara A; Li, Jing; Zhang, Nan; Lobbes, Mark; Zhang, Bin; Mitchell, J Ross

2018-01-01

To evaluate whether the use of a computer-aided diagnosis-contrast-enhanced spectral mammography (CAD-CESM) tool can further increase the diagnostic performance of CESM compared with that of experienced radiologists. This IRB-approved retrospective study analyzed 50 lesions described on CESM from August 2014 to December 2015. Histopathologic analyses, used as the criterion standard, revealed 24 benign and 26 malignant lesions. An expert breast radiologist manually outlined lesion boundaries on the different views. A set of morphologic and textural features were then extracted from the low-energy and recombined images. Machine-learning algorithms with feature selection were used along with statistical analysis to reduce, select, and combine features. Selected features were then used to construct a predictive model using a support vector machine (SVM) classification method in a leave-one-out-cross-validation approach. The classification performance was compared against the diagnostic predictions of 2 breast radiologists with access to the same CESM cases. Based on the SVM classification, CAD-CESM correctly identified 45 of 50 lesions in the cohort, resulting in an overall accuracy of 90%. The detection rate for the malignant group was 88% (3 false-negative cases) and 92% for the benign group (2 false-positive cases). Compared with the model, radiologist 1 had an overall accuracy of 78% and a detection rate of 92% (2 false-negative cases) for the malignant group and 62% (10 false-positive cases) for the benign group. Radiologist 2 had an overall accuracy of 86% and a detection rate of 100% for the malignant group and 71% (8 false-positive cases) for the benign group. The results of our feasibility study suggest that a CAD-CESM tool can provide complementary information to radiologists, mainly by reducing the number of false-positive findings. Copyright © 2017 Elsevier B.V. All rights reserved.

False-positive iodine-131 whole-body scan findings in patients with differentiated thyroid carcinoma: report of 11 cases and review of the literature.

PubMed

Buton, Leckzinscka; Morel, Olivier; Gault, Patricia; Illouz, Frédéric; Rodien, Patrice; Rohmer, Vincent

2013-07-01

Iodine-131 (I-131) whole-body scan (WBS) plays an important role in the management of patients with differentiated thyroid carcinoma (DTC), to detect normal thyroid remnants and recurrent or metastatic disease. A focus of I-131 accumulation outside the thyroid bed and the areas of physiological uptake is strongly suggestive of a distant functioning metastasis. However, many false-positive I-131 WBS findings have been reported in the literature. We describe a series of 11 personal cases of patients with DTC, collected from 1992 to 2011, in whom diagnostic or post-treatment WBS showed false-positive retention of I-131 in various locations. False-positive accumulations of I-131 on WBS may be classified according to the underlying pathophysiological mechanisms: external and internal contaminations by body secretions, ectopic normal thyroid and gastric tissues, inflammatory and infectious diseases, benign and malignant tumors, cysts and effusions of serous cavities, thymic uptake, and other non classified causes. Clinicians must be aware of possible false-positive findings to avoid misinterpretations of the I-131 WBS, which could lead to inappropriate treatments. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

A case of positive 68Ga-DOTATOC-PET/CT pancreatic heterotopia mimicking an intestinal neuroendocrine tumor.

PubMed

Zilli, Alessandra; Fanetti, Ilaria; Conte, Dario; Massironi, Sara

Gallium-68 DOTA-peptide positron emission tomography/computed tomography ( 68 Ga-PET/CT) has emerged as a promising tool for the diagnosis and staging of gastro-entero-pancreatic neoplasms, thanks to its high sensitivity and specificity. Heterotopic pancreas, which is relatively rare, has never been reported as a possible cause of false positives of 68 Ga-PET/CT. We report on the first case of a heterotopic pancreas showing pathological uptake at 68 Ga-PET/CT, thus mimicking an intestinal neuroendocrine tumor. The present case suggests that heterotopic pancreas should be included among the possible causes of false positives at 68 Ga PET. Copyright © 2018 Elsevier Inc. All rights reserved.

Advance in diagnosis of female genital tract tumor with laser fluorescence

NASA Astrophysics Data System (ADS)

Ding, Ai-Hua; Tseng, Quen; Lian, Shao-Hui

1998-11-01

In order to improve the diagnostic accuracy of malignant tumors with laser fluorescence, in 1996, our group successfully created the computerized laser fluorescence spectrograph type II with more reliable images shown overshadowing the naked eye method before 74 cases of female genital tract diseases had been examined by the LFS II resulting in 10 positive cases which were also proven pathologically as malignant tumors, without nay false negative, 3 cases presented suspicious positive but all were proven pathologically as non-tumors lesions, the false positive rate was 4 percent. Our work showed that the method of LFS II can provide a more rapid and accurate diagnosis for the clinical malignant tumors.

False negative rates in Drosophila cell-based RNAi screens: a case study

PubMed Central

2011-01-01

Background High-throughput screening using RNAi is a powerful gene discovery method but is often complicated by false positive and false negative results. Whereas false positive results associated with RNAi reagents has been a matter of extensive study, the issue of false negatives has received less attention. Results We performed a meta-analysis of several genome-wide, cell-based Drosophila RNAi screens, together with a more focused RNAi screen, and conclude that the rate of false negative results is at least 8%. Further, we demonstrate how knowledge of the cell transcriptome can be used to resolve ambiguous results and how the number of false negative results can be reduced by using multiple, independently-tested RNAi reagents per gene. Conclusions RNAi reagents that target the same gene do not always yield consistent results due to false positives and weak or ineffective reagents. False positive results can be partially minimized by filtering with transcriptome data. RNAi libraries with multiple reagents per gene also reduce false positive and false negative outcomes when inconsistent results are disambiguated carefully. PMID:21251254

Diagnostic accuracy of contrast-enhanced spectral mammography in comparison to conventional full-field digital mammography in a population of women with dense breasts.

PubMed

Mori, Miki; Akashi-Tanaka, Sadako; Suzuki, Satoko; Daniels, Murasaki Ikeda; Watanabe, Chie; Hirose, Masanori; Nakamura, Seigo

2017-01-01

Contrast-enhanced spectral mammography to compare clinical efficacy of contrast-enhanced spectral mammography (CESM) and conventional digital mammography (MMG) with histopathology as gold standard in dense breasts. A total of 143 breasts of 72 women who underwent CESM and MMG between 2011 and 2014 at Showa University Hospital were analyzed. 129 (90.2 %) of 143 breasts revealed dense breasts on MMG. 58 (40.6 %) of 143 breasts were diagnosed with breast cancer at histopathology. The remaining 85 breasts were diagnosed with benign findings after image assessments and/or core needle biopsy. CESM revealed 8 false-negative cases among 58 breast cancer cases (sensitivity 86.2 %) and 5 false-positive cases (specificity 94.1 %). Accuracy was 90.9 %. Conventional MMG was assessed true positive in 31 of 58 breast cancer cases (sensitivity 53.4 %) and false positive in 12 cases (specificity 85.9 %). Accuracy was 72.7 %. Sensitivity (p < 0.001), specificity (p = 0.016) and accuracy (p < 0.001) were significantly higher on CESM compared to MMG. MMG missed malignancy in 27 breasts. Of these, 25 were dense breasts. Of these 25, 20 (80.0 %) breasts were positive on CESM. These findings suggest that CESM offers superior clinical performance compared to MMG. Use of CESM may decrease false negatives especially for women with dense breasts.

CT Colonography with Computer-aided Detection: Recognizing the Causes of False-Positive Reader Results

PubMed Central

Dachman, Abraham H.; Wroblewski, Kristen; Vannier, Michael W.; Horne, John M.

2014-01-01

Computed tomography (CT) colonography is a screening modality used to detect colonic polyps before they progress to colorectal cancer. Computer-aided detection (CAD) is designed to decrease errors of detection by finding and displaying polyp candidates for evaluation by the reader. CT colonography CAD false-positive results are common and have numerous causes. The relative frequency of CAD false-positive results and their effect on reader performance on the basis of a 19-reader, 100-case trial shows that the vast majority of CAD false-positive results were dismissed by readers. Many CAD false-positive results are easily disregarded, including those that result from coarse mucosa, reconstruction, peristalsis, motion, streak artifacts, diverticulum, rectal tubes, and lipomas. CAD false-positive results caused by haustral folds, extracolonic candidates, diminutive lesions (<6 mm), anal papillae, internal hemorrhoids, varices, extrinsic compression, and flexural pseudotumors are almost always recognized and disregarded. The ileocecal valve and tagged stool are common sources of CAD false-positive results associated with reader false-positive results. Nondismissable CAD soft-tissue polyp candidates larger than 6 mm are another common cause of reader false-positive results that may lead to further evaluation with follow-up CT colonography or optical colonoscopy. Strategies for correctly evaluating CAD polyp candidates are important to avoid pitfalls from common sources of CAD false-positive results. ©RSNA, 2014 PMID:25384290

[Interpretation of false positive results of biochemical prenatal tests].

PubMed

Sieroszewski, Piotr; Słowakiewicz, Katarzyna; Perenc, Małgorzata

2010-03-01

Modern, non-invasive prenatal diagnostics based on biochemical and ultrasonographic markers of fetal defects allows us to calculate the risk of fetal chromosomal aneuploidies with high sensitivity and specificity An introduction of biochemical, non-invasive prenatal tests turned out to result in frequent false positive results of these tests in cases when invasive diagnostics does not confirm fetal defects. However prospective analysis of these cases showed numerous complications in the third trimester of the pregnancies.

Screening for Sex Chromosome Aneuploidy by Cell-Free DNA Testing: Patient Choice and Performance.

PubMed

Bevilacqua, Elisa; Ordóñez, Elena; Hurtado, Ivan; Rueda, Laura; Mazzone, Eléonora; Cirigliano, Vincenzo; Jani, Jacques C

2017-08-23

To study patient choice regarding testing for sex chromosome aneuploidy (SCA) and the performance of cell-free DNA (cfDNA) screening for SCA. Patient choice regarding screening for SCA and factors influencing this choice were evaluated in a single center. In a subsequent two-center study, cases that screened positive for SCA were analyzed to determine the positive predictive value (PPV) for each SCA. In all, 1,957 (61.9%) of the 3,162 patients undergoing cfDNA testing opted for SCA screening. Regression analysis demonstrated that independent predictors of a patient's decision for SCA were earlier gestational age, spontaneous conception, and cfDNA chosen as a primary method of screening. A total of 161 cases screened positive for SCA and follow-up data were available for 118 (73.3%). Forty-six of the 61 cases of 45,X were false-positive results and 15 were concordant with the fetal karyotype (PPV = 24.6%). Seventeen of the 22 cases of 47,XXX were false positive and 5 concordant (PPV = 22.7%). Eleven of the 30 cases of 47,XXY were false positive and 19 concordant (PPV = 63.3%). All 5 cases of 47,XYY were correctly identified, thus yielding a PPV of 100%. More than half of the patients undergoing cfDNA aneuploidy screening also opted for SCA testing, but they were less likely to do so in the presence of an increased risk of trisomy. SCAs involving the X chromosome had a lower PPV than those involving the Y chromosome. © 2017 S. Karger AG, Basel.

Early Disseminated Lyme Disease Causing False-Positive Serology for Primary Epstein-Barr Virus Infection: Report of 2 Cases.

PubMed

Pavletic, Adriana J; Marques, Adriana R

2017-07-15

False-positive serology for Lyme disease was reported in patients with acute infectious mononucleosis. Here we describe 2 patients with early disseminated Lyme disease who were misdiagnosed with infectious mononucleosis based on false-positive tests for primary Epstein-Barr virus infection. Published by Oxford University Press for the Infectious Diseases Society of America 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

An assessment of public health surveillance of Zika virus infection and potentially associated outcomes in Latin America.

PubMed

Bautista, Leonelo E; Herrera, Víctor M

2018-05-24

We evaluated whether outbreaks of Zika virus (ZIKV) infection, newborn microcephaly, and Guillain-Barré syndrome (GBS) in Latin America may be detected through current surveillance systems, and how cases detected through surveillance may increase health care burden. We estimated the sensitivity and specificity of surveillance case definitions using published data. We assumed a 10% ZIKV infection risk during a non-outbreak period and hypothetical increases in risk during an outbreak period. We used sensitivity and specificity estimates to correct for non-differential misclassification, and calculated a misclassification-corrected relative risk comparing both periods. To identify the smallest hypothetical increase in risk resulting in a detectable outbreak we compared the misclassification-corrected relative risk to the relative risk corresponding to the upper limit of the endemic channel (mean + 2 SD). We also estimated the proportion of false positive cases detected during the outbreak. We followed the same approach for microcephaly and GBS, but assumed the risk of ZIKV infection doubled during the outbreak, and ZIKV infection increased the risk of both diseases. ZIKV infection outbreaks were not detectable through non-serological surveillance. Outbreaks were detectable through serologic surveillance if infection risk increased by at least 10%, but more than 50% of all cases were false positive. Outbreaks of severe microcephaly were detected if ZIKV infection increased prevalence of this condition by at least 24.0 times. When ZIKV infection did not increase the prevalence of severe microcephaly, 34.7 to 82.5% of all cases were false positive, depending on diagnostic accuracy. GBS outbreaks were detected if ZIKV infection increased the GBS risk by at least seven times. For optimal GBS diagnosis accuracy, the proportion of false positive cases ranged from 29 to 54% and from 45 to 56% depending on the incidence of GBS mimics. Current surveillance systems have a low probability of detecting outbreaks of ZIKV infection, severe microcephaly, and GBS, and could result in significant increases in health care burden, due to the detection of large numbers of false positive cases. In view of these limitations, Latin American countries should consider alternative options for surveillance.

Six consecutive false positive cases from cell-free fetal DNA testing in a single referring centre

PubMed Central

Dugo, Nella; Padula, Francesco; Mobili, Luisa; Brizzi, Cristiana; D’Emidio, Laura; Cignini, Pietro; Mesoraca, Alvaro; Bizzoco, Domenico; Cima, Antonella; Giorlandino, Claudio

2014-01-01

Introduction recent studies have proposed the introduction of cell-free fetal DNA testing (NIPT-Non Invasive Prenatal Testing) in routine clinical practice emphasizing its high sensibility and specificity. In any case, false positive and false negative findings may result from placental mosaicism, because cell-free fetal DNA originates mainly from placenta. Case we report six cases of women who underwent chorionic villus sampling (CVS) or amniocentesis to confirm the results from NIPT: two Turner syndromes, two Triple X, one Patau syndrome, one Edward syndrome. Results using classic cytogenetic analysis and, also, Array - Comparative Genomic Hybridization (Array CGH) the karyotype of all 5 fetuses was found to be normal. Conclusion results from NIPT must always be confirmed by invasive prenatal diagnosis. It is mandatory to inform the patient that the CVS and amniocentesis still represent the only form of prenatal diagnostic test available. PMID:25332757

Cost-effectiveness of WHO-Recommended Algorithms for TB Case Finding at Ethiopian HIV Clinics.

PubMed

Adelman, Max W; McFarland, Deborah A; Tsegaye, Mulugeta; Aseffa, Abraham; Kempker, Russell R; Blumberg, Henry M

2018-01-01

The World Health Organization (WHO) recommends active tuberculosis (TB) case finding and a rapid molecular diagnostic test (Xpert MTB/RIF) to detect TB among people living with HIV (PLHIV) in high-burden settings. Information on the cost-effectiveness of these recommended strategies is crucial for their implementation. We conducted a model-based cost-effectiveness analysis comparing 2 algorithms for TB screening and diagnosis at Ethiopian HIV clinics: (1) WHO-recommended symptom screen combined with Xpert for PLHIV with a positive symptom screen and (2) current recommended practice algorithm (CRPA; based on symptom screening, smear microscopy, and clinical TB diagnosis). Our primary outcome was US$ per disability-adjusted life-year (DALY) averted. Secondary outcomes were additional true-positive diagnoses, and false-negative and false-positive diagnoses averted. Compared with CRPA, combining a WHO-recommended symptom screen with Xpert was highly cost-effective (incremental cost of $5 per DALY averted). Among a cohort of 15 000 PLHIV with a TB prevalence of 6% (900 TB cases), this algorithm detected 8 more true-positive cases than CRPA, and averted 2045 false-positive and 8 false-negative diagnoses compared with CRPA. The WHO-recommended algorithm was marginally costlier ($240 000) than CRPA ($239 000). In sensitivity analysis, the symptom screen/Xpert algorithm was dominated at low Xpert sensitivity (66%). In this model-based analysis, combining a WHO-recommended symptom screen with Xpert for TB diagnosis among PLHIV was highly cost-effective ($5 per DALY averted) and more sensitive than CRPA in a high-burden, resource-limited setting.

Impact of false-negative sentinel lymph node biopsy on survival in patients with cutaneous melanoma.

PubMed

Caracò, C; Marone, U; Celentano, E; Botti, G; Mozzillo, N

2007-09-01

Sentinel lymph node biopsy is widely accepted as standard care in melanoma despite lack of pertinent randomized trials results. A possible pitfall of this procedure is the inaccurate identification of the sentinel lymph node leading to biopsy and analysis of a nonsentinel node. Such a technical failure may yield a different prognosis. The purpose of this study is to analyze the incidence of false negativity and its impact on clinical outcome and to try to understand its causes. The Melanoma Data Base at National Cancer Institute of Naples was analyzed comparing results between false-negative and tumor-positive sentinel node patients focusing on overall survival and prognostic factors influencing the clinical outcome. One hundred fifty-one cases were diagnosed to be tumor-positive after sentinel lymph node biopsy and were subjected to complete lymph node dissection. Thirty-four (18.4%)patients with tumor-negative sentinel node subsequently developed lymph node metastases in the basin site of the sentinel procedure. With a median follow-up of 42.8 months the 5-year overall survival was 48.4% and 66.3% for false-negative and tumor-positive group respectively with significant statistical differences (P < .03). The sensitivity of sentinel lymph node biopsy was 81.6%, and a regional nodal basin recurrence after negative-sentinel node biopsy means a worse prognosis, compared with patients submitted to complete lymph node dissection after a positive sentinel biopsy. The evidence of higher number of tumor-positive nodes after delayed lymphadenectomy in false-negative group compared with tumor-positive sentinel node cases, confirmed the importance of an early staging of lymph nodal involvement. Further data will better clarify the role of prognostic factors to identify cases with a more aggressive biological behavior of the disease.

When the Single Matters more than the Group (II): Addressing the Problem of High False Positive Rates in Single Case Voxel Based Morphometry Using Non-parametric Statistics.

PubMed

Scarpazza, Cristina; Nichols, Thomas E; Seramondi, Donato; Maumet, Camille; Sartori, Giuseppe; Mechelli, Andrea

2016-01-01

In recent years, an increasing number of studies have used Voxel Based Morphometry (VBM) to compare a single patient with a psychiatric or neurological condition of interest against a group of healthy controls. However, the validity of this approach critically relies on the assumption that the single patient is drawn from a hypothetical population with a normal distribution and variance equal to that of the control group. In a previous investigation, we demonstrated that family-wise false positive error rate (i.e., the proportion of statistical comparisons yielding at least one false positive) in single case VBM are much higher than expected (Scarpazza et al., 2013). Here, we examine whether the use of non-parametric statistics, which does not rely on the assumptions of normal distribution and equal variance, would enable the investigation of single subjects with good control of false positive risk. We empirically estimated false positive rates (FPRs) in single case non-parametric VBM, by performing 400 statistical comparisons between a single disease-free individual and a group of 100 disease-free controls. The impact of smoothing (4, 8, and 12 mm) and type of pre-processing (Modulated, Unmodulated) was also examined, as these factors have been found to influence FPRs in previous investigations using parametric statistics. The 400 statistical comparisons were repeated using two independent, freely available data sets in order to maximize the generalizability of the results. We found that the family-wise error rate was 5% for increases and 3.6% for decreases in one data set; and 5.6% for increases and 6.3% for decreases in the other data set (5% nominal). Further, these results were not dependent on the level of smoothing and modulation. Therefore, the present study provides empirical evidence that single case VBM studies with non-parametric statistics are not susceptible to high false positive rates. The critical implication of this finding is that VBM can be used to characterize neuroanatomical alterations in individual subjects as long as non-parametric statistics are employed.

[Prospective performance evaluation of first trimester screenings in Germany for risk calculation through http://www.firsttrimester.net].

PubMed

Kleinsorge, F; Smetanay, K; Rom, J; Hörmansdörfer, C; Hörmannsdörfer, C; Scharf, A; Schmidt, P

2010-12-01

In 2008, 2 351 first trimester screenings were calculated by a newly developed internet database ( http:// www.firsttrimester.net ) to evaluate the risk for the presence of Down's syndrome. All data were evaluated by the conventional first trimester screening according to Nicolaides (FTS), based on the previous JOY Software, and by the advanced first trimester screening (AFS). After receiving the feedback of the karyotype as well as the rates of the correct positives, correct negatives, false positives, false negatives, the sensitivity and specificity were calculated and compared. Overall 255 cases were investigated which were analysed by both methods. These included 2 cases of Down's syndrome and one case of trisomy 18. The FTS and the AFS had a sensitivity of 100%. The specificity was 88.5% for the FTS and 93.0% for the AFS. As already shown in former studies, the higher specificity of the AFS is a result of a reduction of the false positive rate (28 to 17 cases). As a consequence of the AFS with a detection rate of 100% the rate of further invasive diagnostics in pregnant women is decreased by having 39% fewer positive tested women. © Georg Thieme Verlag KG Stuttgart · New York.

False positive computed tomographic angiography for Stanford type A aortic dissection.

PubMed

Bandali, Murad F; Hatem, Muhammed A; Appoo, Jehangir J; Hutchison, Stuart J; Wong, Jason K

2015-12-01

Computed tomographic angiography (CTA) has emerged as the defacto imaging test to rule out acute aortic dissection; however, it is not without flaws. We report a case of a false-positive CTA with respect to Stanford Type A aortic dissection. A 52 year-old male presented with sudden onset shortness of breath. He denied chest pain. Due to severe hypertension and an Emergency Department bedside ultrasound suggesting an intimal flap in the aorta, CTA was requested to better assess the ascending aorta and was interpreted as consistent with Stanford Type A aortic dissection with thrombosis of the false lumen in the ascending aorta. However, intra-operative imaging (TEE and epi-aortic scanning) did not identify an intimal flap or dissection, and neither did definitive surgical inspection of the aorta. The suspected aortic dissection and thrombosed false lumen were not visualized on repeat CTA two days later. False positive diagnosis of Stanford Type A aortic dissection on CTA can be the result of technical factors, streak artifacts, motion artifacts, and periaortic structures. In this case, non-uniform arterial contrast enhancement secondary to unrecognized biventricular dysfunction resulted in the false positive CTA appearance of an intimal flap and mural thrombus. Intra-operative TEE and epi-aortic scanning were proven correct in excluding aortic dissection by the standard of definitive surgical inspection of the aorta.

Sensitivity and Specificity of Histoplasma Antigen Detection by Enzyme Immunoassay.

PubMed

Cunningham, Lauren; Cook, Audrey; Hanzlicek, Andrew; Harkin, Kenneth; Wheat, Joseph; Goad, Carla; Kirsch, Emily

2015-01-01

The objective of this study was to evaluate the sensitivity and specificity of an antigen enzyme immunoassay (EIA) on urine samples for the diagnosis of histoplasmosis in dogs. This retrospective medical records review included canine cases with urine samples submitted for Histoplasma EIA antigen assay between 2007 and 2011 from three veterinary institutions. Cases for which urine samples were submitted for Histoplasma antigen testing were reviewed and compared to the gold standard of finding Histoplasma organisms or an alternative diagnosis on cytology or histopathology. Sensitivity, specificity, negative predictive value, positive predictive value, and the kappa coefficient and associated confidence interval were calculated for the EIA-based Histoplasma antigen assay. Sixty cases met the inclusion criteria. Seventeen cases were considered true positives based on identification of the organism, and 41 cases were considered true negatives with an alternative definitive diagnosis. Two cases were considered false negatives, and there were no false positives. Sensitivity was 89.47% and the negative predictive value was 95.35%. Specificity and the positive predictive value were both 100%. The kappa coefficient was 0.9207 (95% confidence interval, 0.8131-1). The Histoplasma antigen EIA test demonstrated high specificity and sensitivity for the diagnosis of histoplasmosis in dogs.

Case report: false negative serum cryptococcal latex agglutination test in a patient with disseminated cryptococcal disease.

PubMed

Navabi, Nazlee; Montebatsi, Milton; Scott, Michelle; Gluckman, Stephen J; Reid, Michael J A

2015-01-01

A case of false-negative serum latex agglutination cryptococcal antigen (CRAG) test in a 45-year-old HIV-positive male with Cryptococcus-positive culture is described. The patient was presented to a hospital in Botswana, with breathlessness and a diffuse papular rash. His CD4 count was 25 cells/μL. Despite the suspicion for disseminated cryptococcal disease, an initial serum CRAG latex test was negative. Results of subsequent Indian ink staining, culture of cerebrospinal fluid and skin scrapings, and serum lateral flow immunoassay (LFA) were all positive for Cryptococcus neoformans. There are several possible explanations for the false-negative CRAG latex test. Given the positive LFA result, we speculate that disease may have been caused by Cryptococcus gattii, which is estimated to be responsible for between 15% and 30% of all cryptococcal diseases in Botswana. Reduced sensitivity of CRAG latex assays for detecting C gattii may lead to underdiagnosis of cryptococcal infection. © The Author(s) 2014.

Signal detection of adverse events with imperfect confirmation rates in vaccine safety studies using self-controlled case series design.

PubMed

Xu, Stanley; Newcomer, Sophia; Nelson, Jennifer; Qian, Lei; McClure, David; Pan, Yi; Zeng, Chan; Glanz, Jason

2014-05-01

The Vaccine Safety Datalink project captures electronic health record data including vaccinations and medically attended adverse events on 8.8 million enrollees annually from participating managed care organizations in the United States. While the automated vaccination data are generally of high quality, a presumptive adverse event based on diagnosis codes in automated health care data may not be true (misclassification). Consequently, analyses using automated health care data can generate false positive results, where an association between the vaccine and outcome is incorrectly identified, as well as false negative findings, where a true association or signal is missed. We developed novel conditional Poisson regression models and fixed effects models that accommodate misclassification of adverse event outcome for self-controlled case series design. We conducted simulation studies to evaluate their performance in signal detection in vaccine safety hypotheses generating (screening) studies. We also reanalyzed four previously identified signals in a recent vaccine safety study using the newly proposed models. Our simulation studies demonstrated that (i) outcome misclassification resulted in both false positive and false negative signals in screening studies; (ii) the newly proposed models reduced both the rates of false positive and false negative signals. In reanalyses of four previously identified signals using the novel statistical models, the incidence rate ratio estimates and statistical significances were similar to those using conventional models and including only medical record review confirmed cases. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Similarity based false-positive reduction for breast cancer using radiographic and pathologic imaging features

NASA Astrophysics Data System (ADS)

Pai, Akshay; Samala, Ravi K.; Zhang, Jianying; Qian, Wei

2010-03-01

Mammography reading by radiologists and breast tissue image interpretation by pathologists often leads to high False Positive (FP) Rates. Similarly, current Computer Aided Diagnosis (CADx) methods tend to concentrate more on sensitivity, thus increasing the FP rates. A novel method is introduced here which employs similarity based method to decrease the FP rate in the diagnosis of microcalcifications. This method employs the Principal Component Analysis (PCA) and the similarity metrics in order to achieve the proposed goal. The training and testing set is divided into generalized (Normal and Abnormal) and more specific (Abnormal, Normal, Benign) classes. The performance of this method as a standalone classification system is evaluated in both the cases (general and specific). In another approach the probability of each case belonging to a particular class is calculated. If the probabilities are too close to classify, the augmented CADx system can be instructed to have a detailed analysis of such cases. In case of normal cases with high probability, no further processing is necessary, thus reducing the computation time. Hence, this novel method can be employed in cascade with CADx to reduce the FP rate and also avoid unnecessary computational time. Using this methodology, a false positive rate of 8% and 11% is achieved for mammography and cellular images respectively.

Interval Breast Cancer Rates and Histopathologic Tumor Characteristics after False-Positive Findings at Mammography in a Population-based Screening Program.

PubMed

Hofvind, Solveig; Sagstad, Silje; Sebuødegård, Sofie; Chen, Ying; Roman, Marta; Lee, Christoph I

2018-04-01

Purpose To compare rates and tumor characteristics of interval breast cancers (IBCs) detected after a negative versus false-positive screening among women participating in the Norwegian Breast Cancer Screening Program. Materials and Methods The Cancer Registry Regulation approved this retrospective study. Information about 423 445 women aged 49-71 years who underwent 789 481 full-field digital mammographic screening examinations during 2004-2012 was extracted from the Cancer Registry of Norway. Rates and odds ratios of IBC among women with a negative (the reference group) versus a false-positive screening were estimated by using logistic regression models adjusted for age at diagnosis and county of residence. Results A total of 1302 IBCs were diagnosed after 789 481 screening examinations, of which 7.0% (91 of 1302) were detected among women with a false-positive screening as the most recent breast imaging examination before detection. By using negative screening as the reference, adjusted odds ratios of IBCs were 3.3 (95% confidence interval [CI]: 2.6, 4.2) and 2.8 (95% CI: 1.8, 4.4) for women with a false-positive screening without and with needle biopsy, respectively. Women with a previous negative screening had a significantly lower proportion of tumors that were 10 mm or less (14.3% [150 of 1049] vs 50.0% [seven of 14], respectively; P < .01) and grade I tumors (13.2% [147 of 1114] vs 42.9% [six of 14]; P < .01), but a higher proportion of cases with lymph nodes positive for cancer (40.9% [442 of 1080] vs 13.3% [two of 15], respectively; P = .03) compared with women with a previous false-positive screening with benign biopsy. A retrospective review of the screening mammographic examinations identified 42.9% (39 of 91) of the false-positive cases to be the same lesion as the IBC. Conclusion By using a negative screening as the reference, a false-positive screening examination increased the risk of an IBC three-fold. The tumor characteristics of IBC after a negative screening were less favorable compared with those detected after a previous false-positive screening. © RSNA, 2017 Online supplemental material is available for this article.

[Examination about utility of a Streptococcus pneumoniae capsular antigen swiftness search kit urine in a pneumonia patient].

PubMed

Hashikita, Giichi; Yamaguti, Toshiyuki; Tachi, Yoshimi; Kishi, Etsuko; Kawamura, Toru; Takahashi, Shun; Arai, Yukie; Koyama, Sachie; Huruhata, Toshihumi; Itabashi, Akira; Oka, Yoko; Yamazaki, Tsutomu; Maesaki, Sigefumi

2005-01-01

We investigated the usefullness of Binax NOW urine antigen test, an immunochromatographic assay that binds any soluble Streptococcus pneumoniae antigen (C polysaccharide) for the diagnosis of penumoniae form September 2003 to March 2005. We used 372 samples form the patinets with pneumoniae diagnosed for blood or sputum cultuter or gram-stained sputum smear. Out of 24 culture positive specimens, Binax NOW urine antigen test, showed positive in 18 (75%) specimens. The sensitivity of sputum and blood culture was 71.7% and 83.3%, respectively. Binax NOW urine antigen test was seemed false positives in 55 samples, false negatives in 6 samples. The specificity of Binax NOW urine antigen test was evaluated 84.1%. Overall agreement among tests was 83.6%. When compared to culture, false negative urine antigen may be the result of colonizing S. pneumoniae in sputum or pneumonia caused by an agent other than S. pneumoniae. CRP values for cases were both urine antigen and culture were positive ranged from 40 mg/dl to 10 mg/dl while urine antigen and culture negative cases were predominantly less than 10 mg/dl. Positive blood and pleural fluid culture cases were consistently associated with strongly positive urine antigen tests. Non-agreement between urine antigen, culture, and microscopy may be the result of specimen quality, labile nature of S. pneumoniae and antimicrobial therapy.

Case report of a false positive result of the Xpert® MTB/RIF assay for rifampicin resistance in Mycobacterium tuberculosis complex.

PubMed

Claessens, Jolien; Mathys, Vanessa; Derdelinckx, Inge; Saegeman, Veroniek

2017-06-01

In the present case, we report a false positive result for the detection of rifampicin (RIF) resistance by the Xpert ® MTB/RIF assay, version G4.Miliary Mycobacterium tuberculosis infection (miliary TB) was suspected in a 50-year old Angolan woman. Imaging of the thorax and abdomen displayed diffuse lesions. The Xpert ® MTB/RIF assay conducted on the broncho-alveolar lavage (BAL) fluid was positive for TB and positive for RIF resistance. Confirmatory molecular tests and the phenotypic drug susceptibility determination supported the diagnosis of TB but not RIF resistance. The patient was treated successfully with a conventional therapeutic scheme. Because, the Xpert ® MTB/RIF assay allows the simultaneous detection of TB and RIF resistance, the World Health Organisation (WHO) recommends its use as initial diagnostic test, over microscopy, culture and phenotypic drug susceptibility testing. Even though specificity of the Xpert ® MTB/RIF assay version G4 is high, false positive test results remain possible and have to be considered for the interpretation of the RIF resistance detection by Xpert ® MTB/RIF assay.

Automated detection of tuberculosis on sputum smeared slides using stepwise classification

NASA Astrophysics Data System (ADS)

Divekar, Ajay; Pangilinan, Corina; Coetzee, Gerrit; Sondh, Tarlochan; Lure, Fleming Y. M.; Kennedy, Sean

2012-03-01

Routine visual slide screening for identification of tuberculosis (TB) bacilli in stained sputum slides under microscope system is a tedious labor-intensive task and can miss up to 50% of TB. Based on the Shannon cofactor expansion on Boolean function for classification, a stepwise classification (SWC) algorithm is developed to remove different types of false positives, one type at a time, and to increase the detection of TB bacilli at different concentrations. Both bacilli and non-bacilli objects are first analyzed and classified into several different categories including scanty positive, high concentration positive, and several non-bacilli categories: small bright objects, beaded, dim elongated objects, etc. The morphological and contrast features are extracted based on aprior clinical knowledge. The SWC is composed of several individual classifiers. Individual classifier to increase the bacilli counts utilizes an adaptive algorithm based on a microbiologist's statistical heuristic decision process. Individual classifier to reduce false positive is developed through minimization from a binary decision tree to classify different types of true and false positive based on feature vectors. Finally, the detection algorithm is was tested on 102 independent confirmed negative and 74 positive cases. A multi-class task analysis shows high accordance rate for negative, scanty, and high-concentration as 88.24%, 56.00%, and 97.96%, respectively. A binary-class task analysis using a receiver operating characteristics method with the area under the curve (Az) is also utilized to analyze the performance of this detection algorithm, showing the superior detection performance on the high-concentration cases (Az=0.913) and cases mixed with high-concentration and scanty cases (Az=0.878).

Best research practices in psychology: Illustrating epistemological and pragmatic considerations with the case of relationship science.

PubMed

Finkel, Eli J; Eastwick, Paul W; Reis, Harry T

2015-02-01

In recent years, a robust movement has emerged within psychology to increase the evidentiary value of our science. This movement, which has analogs throughout the empirical sciences, is broad and diverse, but its primary emphasis has been on the reduction of statistical false positives. The present article addresses epistemological and pragmatic issues that we, as a field, must consider as we seek to maximize the scientific value of this movement. Regarding epistemology, this article contrasts the false-positives-reduction (FPR) approach with an alternative, the error balance (EB) approach, which argues that any serious consideration of optimal scientific practice must contend simultaneously with both false-positive and false-negative errors. Regarding pragmatics, the movement has devoted a great deal of attention to issues that frequently arise in laboratory experiments and one-shot survey studies, but it has devoted less attention to issues that frequently arise in intensive and/or longitudinal studies. We illustrate these epistemological and pragmatic considerations with the case of relationship science, one of the many research domains that frequently employ intensive and/or longitudinal methods. Specifically, we examine 6 research prescriptions that can help to reduce false-positive rates: preregistration, prepublication sharing of materials, postpublication sharing of data, close replication, avoiding piecemeal publication, and increasing sample size. For each, we offer concrete guidance not only regarding how researchers can improve their research practices and balance the risk of false-positive and false-negative errors, but also how the movement can capitalize upon insights from research practices within relationship science to make the movement stronger and more inclusive. PsycINFO Database Record (c) 2015 APA, all rights reserved.

Comparison of 4th-Generation HIV Antigen/Antibody Combination Assay With 3rd-Generation HIV Antibody Assays for the Occurrence of False-Positive and False-Negative Results.

PubMed

Muthukumar, Alagarraju; Alatoom, Adnan; Burns, Susan; Ashmore, Jerry; Kim, Anne; Emerson, Brian; Bannister, Edward; Ansari, M Qasim

2015-01-01

To assess the false-positive and false-negative rates of a 4th-generation human immunodeficiency virus (HIV) assay, the Abbott ARCHITECT, vs 2 HIV 3rd-generation assays, the Siemens Centaur and the Ortho-Clinical Diagnostics Vitros. We examined 123 patient specimens. In the first phase of the study, we compared 99 specimens that had a positive screening result via the 3rd-generation Vitros assay (10 positive, 82 negative, and 7 indeterminate via confirmatory immunofluorescent assay [IFA]/Western blot [WB] testing). In the second phase, we assessed 24 HIV-1 RNA-positive (positive result via the nuclear acid amplification test [NAAT] and negative/indeterminate results via the WB test) specimens harboring acute HIV infection. The 4th-generation ARCHITECT assay yielded fewer false-positive results (n = 2) than the 3rd-generation Centaur (n = 9; P = .02) and Vitros (n = 82; P <.001) assays. One confirmed positive case had a false-negative result via the Centaur assay. When specimens from the 24 patients with acute HIV-1 infection were tested, the ARCHITECT assay yielded fewer false-negative results (n = 5) than the Centaur (n = 10) (P = .13) and the other 3rd-generation tests (n = 16) (P = .002). This study indicates that the 4th-generation ARCHITECT HIV assay yields fewer false-positive and false-negative results than the 3rd-generation HIV assays we tested. Copyright© by the American Society for Clinical Pathology (ASCP).

The etiology of Rubella IgM positivity in patients with rubella-like illness in Iran from 2011 to 2013.

PubMed

Khorrami, Seyed Mahmood Seyed; Mokhtari-Azad, Talat; Yavarian, Jila; Nasab, Gazal Sadat Fatemi; Naseri, Maryam; Jandaghi, Nazanin Zahra Shafiei

2015-11-01

Rubella is a mild self-limiting contagious viral disease caused by the rubella virus (RV). Although symptoms are often mild, the concern is centralized around the possible effect on a fetus growth and development in case of primary infection during early months of pregnancy. Recently acquired rubella is commonly confirmed by RV-specific IgM antibody detection in the serum. However, rubella primary infection is not always the only cause of IgM positivity. Other possible causes of rubella IgM positivity may include IgM persistence following vaccination or naturally acquired infection or even re-infection. Moreover, nonspecific IgM reactivity can cause false-positive results. There are few articles to differentiate the aetiology of rash in rubella-like illnesses. However, limited studies have been conducted on clarifying the source of IgM positivity in these cases. This article reports the study of 10,896 clinical cases demonstrating rubella-like illness between 2011 and 2013 in Iran. The rate of IgM positivity among these cases was 0.52% (57 cases). As predicted based on the high coverage of vaccination in Iran fewer than 16% of cases with ELISA IgM positive result, were due to current rubella primary infections. The greater part of the positive IgM reactions occurred in cross reactivity with other viruses (31.6%) or in prolonged IgM response post vaccination (24.6%). This research confirmed that the positive result of rubella IgM assay in vaccinated individuals is mainly caused by prolonged IgM production, rubella re-infection, and false positivity due to infection with other viruses, rather than the rubella primary infection itself. © 2015 Wiley Periodicals, Inc.

A case of placental trisomy 18 mosaicism causing a false negative NIPT result.

PubMed

Yang, Jiexia; Qi, Yiming; Guo, Fangfang; Hou, Yaping; Peng, Haishan; Wang, Dongmei; Oy, Haoxin; Yin, Aihua

2017-01-01

The non-invasive prenatal testing that evaluates circulating cell free DNA, and has been established as an additional pregnancy test for detecting the common fetal trisomies 21, 18 and 13 is rapidly revolutionizing prenatal screening as a result of its increased sensitivity and specificity. However, false positive and false negative results still exist. We presented a case in which the non-invasive prenatal testing results were normal at 15 gestational age (GA), but an ultrasound examination at 30GA showed that the fetus had heart abnormalities, and the third trimester ultrasound at 33GA noted multiple anomalies including a 3.0 mm ventricular septal defect. Along with cordocentesis at 33GA, the cord blood sample cytogenetics analysis showed a mos 47,XN,+18[61]/46,XN[39] T18 karyotype. Six placental biopsies confirmed that the chromosome 18 placenta chimerism ratio had changed from 33% to 72%. Ultimately, the pregnancy was interrupted at 34GA. We presented this case to highlight the need to clearly explain false positive or false negative results to patients. We believe that this information will also influence the development of future diagnostic test methodologies.

[Child psychiatric assessment and the debate regarding the abuse of abuse].

PubMed

Fegert, J M

1995-03-01

The current discussion on false allegations in sexual abuse cases has led to a polarization in the views expressed about the credibility of children. Some authors even speak of a "child sexual accuse syndrome" or of a "sexual abuse allegation in divorce" (SAID) syndrome. A phenomenological analysis of the multiple reasons for misinterpretations is presented. Instead of stressing the importance only of false positives in child sexual abuse questions, an attempt is made to describe reasons for false negatives. Based on a retrospective analysis of 50 consecutive child psychiatric experts in connection with court cases, there does not appear to be an increase in false accusations. Rather, only about one third of the cases even involved suspected sexual abuse. Sexual abuse allegations were much more frequent in girls than in boys. Of 20 abuse allegations we judge four to be false allegations. In only one of these cases, that of an adolescent girl who had been abused in childhood, was the false allegation intended.

Silastic injection for vocal fold medialization resulting in a false-positive finding on F18 FDG-PET/CT.

PubMed

Mahfouz, Ayman; Naji, Meeran; Mok, Wing Yan; Taghi, Ali S; Win, Zarni

2015-09-01

A false-positive uptake of F18-fluorodeoxyglucose (FDG) on positron-emission tomography/computed tomography (PET/CT) can result in confusion and misinterpretation of scans. Such uptakes have been previously described after injection of polytetrafluoroethylene (Teflon) into the vocal folds. Similarly, vocal fold injection of silicone elastomer (Silastic) can result not only in a false-positive FDG uptake on PET/CT, but also in chronic inflammation. We report a case of increased FDG uptake in a vocal fold after Silastic injection that was misinterpreted as a malignancy in a 70-year-old woman who had metastatic carcinoma of the stomach.

False-positive psychology: undisclosed flexibility in data collection and analysis allows presenting anything as significant.

PubMed

Simmons, Joseph P; Nelson, Leif D; Simonsohn, Uri

2011-11-01

In this article, we accomplish two things. First, we show that despite empirical psychologists' nominal endorsement of a low rate of false-positive findings (≤ .05), flexibility in data collection, analysis, and reporting dramatically increases actual false-positive rates. In many cases, a researcher is more likely to falsely find evidence that an effect exists than to correctly find evidence that it does not. We present computer simulations and a pair of actual experiments that demonstrate how unacceptably easy it is to accumulate (and report) statistically significant evidence for a false hypothesis. Second, we suggest a simple, low-cost, and straightforwardly effective disclosure-based solution to this problem. The solution involves six concrete requirements for authors and four guidelines for reviewers, all of which impose a minimal burden on the publication process.

Reducing False Positives in Runtime Analysis of Deadlocks

NASA Technical Reports Server (NTRS)

Bensalem, Saddek; Havelund, Klaus; Clancy, Daniel (Technical Monitor)

2002-01-01

This paper presents an improvement of a standard algorithm for detecting dead-lock potentials in multi-threaded programs, in that it reduces the number of false positives. The standard algorithm works as follows. The multi-threaded program under observation is executed, while lock and unlock events are observed. A graph of locks is built, with edges between locks symbolizing locking orders. Any cycle in the graph signifies a potential for a deadlock. The typical standard example is the group of dining philosophers sharing forks. The algorithm is interesting because it can catch deadlock potentials even though no deadlocks occur in the examined trace, and at the same time it scales very well in contrast t o more formal approaches to deadlock detection. The algorithm, however, can yield false positives (as well as false negatives). The extension of the algorithm described in this paper reduces the amount of false positives for three particular cases: when a gate lock protects a cycle, when a single thread introduces a cycle, and when the code segments in different threads that cause the cycle can actually not execute in parallel. The paper formalizes a theory for dynamic deadlock detection and compares it to model checking and static analysis techniques. It furthermore describes an implementation for analyzing Java programs and its application to two case studies: a planetary rover and a space craft altitude control system.

[Quality assurance of rapid on-site evaluation of CT-guided fine-needle aspiration cytology of lung nodules].

PubMed

Bak, Mihály; Hidvégi, Judit; Andi, Judit; Bahéry, Mária; Kovács, Eszter; Schneider, Ferenc; Kostic, Szilárd; Rényi-Vámos, Ferenc; Szőke, János; Nyári, Tibor; Gődény, Mária; Kásler, Miklós

2013-01-06

The methods available for the diagnosis of lung cancer include radiologic, cytologic and pathologic procedures. The aim of this study was to determine the quality assurance of CT guided fine needle aspiration cytology of lung nodules. Cytology results were rated to 4 categories (positive; suspicious; negative; not representative). All cytology reports were compared with the final histology diagnosis. A total of 128 patients underwent CT-guided percutaneous fine-needle aspiration biopsy cytology (63 males; 65 females; mean age 62.8 years). Smears were adequate in 99 cases and inadequate in 29 cases. The average diameter of the nodules was 3.28 cm. Thirty three (25.6%) of the cases were histologically verified and 2 falsely negative and 2 falsely positive cases were detected. The sensitivity and the positive predictive value were 88.8% and 88.8%, respectively. Pneumothorax developed in 7 (5.4%) cases. These results suggest that CT-guided transthoracic fine needle aspiration cytology has a high diagnostic accuracy and an acceptable complication rate. The auditing valves of the results meet the proposed threshold values.

Investigation into High Barmah Forest Virus Disease Case Numbers Reported in the Northern Territory, Australia in 2012-2013.

PubMed

Kurucz, Nina; Markey, Peter; Draper, Anthony; Melville, Lorna; Weir, Richard; Davis, Steven; Warchot, Allan; Boyd, Rowena; Stokeld, Danielle

2016-02-01

Between October 2012 and October 2013, unprecedented high numbers of Barmah Forest virus (BFV) disease cases were reported in the Northern Territory (NT). An investigation was launched by the NT Department of Health in cooperation with the Department of Primary Industry and Fisheries and the Department of Land Resource Management to investigate possible causes for this phenomenon. The investigation included virus isolations from mosquitoes collected in Darwin urban areas, BFV antibody testing in peri-urban small mammals and a human BFV disease case series investigation of recent cases. No BFV was isolated from the 4641 mosquitoes tested, none of the mammals tested positive for BFV antibodies, and the high BFV disease case numbers did not correlate with the relatively low mosquito vector numbers trapped in 2012-2013. It was estimated that up to 89% of the 79 human cases investigated did not have an acute arboviral illness and therefore had tested falsely positive. An Alere PanBio BFV immunoglobulin M enzyme-linked immunosorbent assay test kit is generally used to test for BFV, with the BFV disease case definition based on immunoglobulin M positives only. Other jurisdictions in Australia also reported high numbers of BFV disease cases, with the majority of the cases suspected to be false positives. Therefore, current testing methods need to be revised to reflect the true numbers of BFV disease cases occurring in Australia and to provide correct diagnoses for patients.

Unreliable alcohol testing in a shipping safety programme.

PubMed

Helander, Anders; Hagelberg, Charlotte Asker; Beck, Olof; Petrini, Björn

2009-08-10

Within a maritime alcohol and drug testing programme, a case showing an unphysiological urine ethanol concentration (235 mmol/L, 10.8 g/L) was found. The sample contained low levels of the ethanol metabolites ethyl glucuronide (EtG) and ethyl sulphate (EtS) which confirmed prior drinking, but also tested positive for the fermenting yeast Candida albicans which suggested post-sampling ethanol formation. This and other questionable cases prompted investigation of the suitability of urine alcohol testing for the intended application. Besides the routine measurements of ethanol, illicit drugs and creatinine, randomly selected ethanol-positive and ethanol-negative urines collected within the maritime programme were checked for the presence of EtG and EtS and for fungal and bacterial growth. Data on sample handling and storage was also gathered. Ten of 15 (67%) ethanol-positive and 4 of 9 (44%) ethanol-negative urines contained yeast and/or bacteria. Among the ethanol-positive cases, 4 (27%) were obviously false positives because EtG and EtS were not detected. Microbial action as the reason for false-high ethanol concentrations was indicated in other cases. When 17 bacteria-infected but fungi-negative urines were supplemented with glucose and stored for 1 week at 21 degrees C, ethanol was formed in 2 specimens containing Escherichia coli and E. coli plus P. aeruginosa. In these samples, EtG was also formed on storage while EtS was not. The routines employed for urine collection and handling within this substance abuse programme caused many false-positive identifications of alcohol use with unintended medico-legal consequences. Unpreserved urines stored without cooling should not be used for alcohol testing, given the high risk for microbial interference.

True detection limits in an experimental linearly heteroscedastic system.. Part 2

NASA Astrophysics Data System (ADS)

Voigtman, Edward; Abraham, Kevin T.

2011-11-01

Despite much different processing of the experimental fluorescence detection data presented in Part 1, essentially the same estimates were obtained for the true theoretical Currie decision levels ( YC and XC) and true Currie detection limits ( YD and XD). The obtained experimental values, for 5% probability of false positives and 5% probability of false negatives, were YC = 56.0 mV, YD = 125. mV, XC = 0.132 μg/mL and XD = 0.293 μg/mL. For 5% probability of false positives and 1% probability of false negatives, the obtained detection limits were YD = 158 . mV and XD = 0.371 μg/mL. Furthermore, by using bootstrapping methodology on the experimental data for the standards and the analytical blank, it was possible to validate previously published experimental domain expressions for the decision levels ( yC and xC) and detection limits ( yD and xD). This was demonstrated by testing the generated decision levels and detection limits for their performance in regard to false positives and false negatives. In every case, the obtained numbers of false negatives and false positives were as specified a priori.

Inflammatory disorders mimicking periprosthetic joint infections may result in false positive α-defensin.

PubMed

Plate, Andreas; Stadler, Laura; Sutter, Reto; Anagnostopoulos, Alexia; Frustaci, Dario; Zbinden, Reinhard; Fucentese, Sandro F; Zinkernagel, Annelies S; Zingg, Patrick O; Achermann, Yvonne

2018-02-26

The antimicrobial peptide α-defensin has recently been introduced as potential "single" biomarker with a high sensitivity and specificity for the preoperative diagnosis of periprosthetic joint infections (PJIs). However, most studies assessed the benefits of the test with exclusion of patients with rheumatic diseases. We aimed to evaluate the α-defensin test in a cohort study without exclusion of cases with inflammatory diseases. Between June 2016 and June 2017, we prospectively included cases with a suspected PJI and an available lateral flow test α-defensin (Synovasure®) in synovial fluid. We compared the test result to the diagnostic criteria for PJIs published by an International Consensus Group in 2013. We included 109 cases (49 hips, 60 knees) in which preoperative α-defensin tests had been performed. Thereof, 20 PJIs (16 hips, 4 knees) were diagnosed. Preoperative α-defensin tests were positive in 25 cases (22.9%) with a test sensitivity and specificity of 90% and 92.1% (95% confidence interval [CI], 68.3 - 98.8% and 84.5 - 96.8%, respectively), and a high negative predictive value of 97.6% (95% CI, 91.7 - 99.4%). We interpreted seven α-defensin tests as false positive, mainly in cases with inflammatory rheumatic diseases, including crystal deposition diseases. A negative synovial α-defensin test can reliably rule out a PJI. However, the test can be false positive in conjunction with an underlying non-infectious inflammatory disease. We therefore propose to use the α-defensin test only in addition to MSIS criteria and assessment for crystals in synovial aspirates. Copyright © 2018. Published by Elsevier Ltd.

Automatic lung nodule graph cuts segmentation with deep learning false positive reduction

NASA Astrophysics Data System (ADS)

Sun, Wenqing; Huang, Xia; Tseng, Tzu-Liang Bill; Qian, Wei

2017-03-01

To automatic detect lung nodules from CT images, we designed a two stage computer aided detection (CAD) system. The first stage is graph cuts segmentation to identify and segment the nodule candidates, and the second stage is convolutional neural network for false positive reduction. The dataset contains 595 CT cases randomly selected from Lung Image Database Consortium and Image Database Resource Initiative (LIDC/IDRI) and the 305 pulmonary nodules achieved diagnosis consensus by all four experienced radiologists were our detection targets. Consider each slice as an individual sample, 2844 nodules were included in our database. The graph cuts segmentation was conducted in a two-dimension manner, 2733 lung nodule ROIs are successfully identified and segmented. With a false positive reduction by a seven-layer convolutional neural network, 2535 nodules remain detected while the false positive dropped to 31.6%. The average F-measure of segmented lung nodule tissue is 0.8501.

False positive malaria rapid diagnostic test in returning traveler with typhoid fever.

PubMed

Meatherall, Bonnie; Preston, Keith; Pillai, Dylan R

2014-07-09

Rapid diagnostic tests play a pivotal role in the early diagnosis of malaria where microscopy or polymerase chain reaction are not immediately available. We report the case of a 39 year old traveler to Canada who presented with fever, headache, and abdominal pain after visiting friends and relatives in India. While in India, the individual was not ill and had no signs or symptoms of malaria. Laboratory testing upon his return to Canada identified a false positive malaria rapid diagnostic (BinaxNOW® malaria) result for P. falciparum with coincident Salmonella Typhi bacteraemia without rheumatoid or autoimmune factors. Rapid diagnostic test false positivity for malaria coincided with the presence or absence of Salmonella Typhi in the blood. Clinicians should be aware that Salmonella Typhi infection may result in a false positive malaria rapid diagnostic test. The mechanism of this cross-reactivity is not clear.

Cytokines in pleural liquid for diagnosis of tuberculous pleurisy.

PubMed

Yamada, Y; Nakamura, A; Hosoda, M; Kato, T; Asano, T; Tonegawa, K; Itoh, M

2001-07-01

An elevated level of adenosine deaminase (ADA) in pleural liquid has been considered as a supplemental diagnostic marker for tuberculous pleurisy. However, this is complicated by false-positives and -negatives. Recently, it has been revealed that various cytokines are intimately involved in the pathognomonic physiology of tuberculosis. In this study, interleukin-8 (IL-8), tumour necrosis factor alpha (TNFalpha) and interferon gamma (IFNgamma) were compared with ADA in pleural liquid of patients with inflammatory (21 cases), malignant (28 cases) and tuberculous (21 cases) disease. The pleural ADA, IL-8, TNFalpha and IFNgamma levels in the tuberculous group were higher than in the other three groups. Analysis of receiver operating characteristic (ROC) curves, to evaluate the utility of the various parameters, demonstrates values for the area under the curve (AUC) of 0.770, 0.875, 0.892 and 0.987, respectively for IL-8, TNFalpha, ADA and IFNgamma. No false-positives were encountered with IFNgamma and only one case with a small volume of pleural liquid was a false-negative. This indicates that IFNgamma is a very reliable marker of tuberculous pleurisy.

Proteins interacting with cloning scars: a source of false positive protein-protein interactions.

PubMed

Banks, Charles A S; Boanca, Gina; Lee, Zachary T; Florens, Laurence; Washburn, Michael P

2015-02-23

A common approach for exploring the interactome, the network of protein-protein interactions in cells, uses a commercially available ORF library to express affinity tagged bait proteins; these can be expressed in cells and endogenous cellular proteins that copurify with the bait can be identified as putative interacting proteins using mass spectrometry. Control experiments can be used to limit false-positive results, but in many cases, there are still a surprising number of prey proteins that appear to copurify specifically with the bait. Here, we have identified one source of false-positive interactions in such studies. We have found that a combination of: 1) the variable sequence of the C-terminus of the bait with 2) a C-terminal valine "cloning scar" present in a commercially available ORF library, can in some cases create a peptide motif that results in the aberrant co-purification of endogenous cellular proteins. Control experiments may not identify false positives resulting from such artificial motifs, as aberrant binding depends on sequences that vary from one bait to another. It is possible that such cryptic protein binding might occur in other systems using affinity tagged proteins; this study highlights the importance of conducting careful follow-up studies where novel protein-protein interactions are suspected.

Proteins interacting with cloning scars: a source of false positive protein-protein interactions

PubMed Central

Banks, Charles A. S.; Boanca, Gina; Lee, Zachary T.; Florens, Laurence; Washburn, Michael P.

2015-01-01

A common approach for exploring the interactome, the network of protein-protein interactions in cells, uses a commercially available ORF library to express affinity tagged bait proteins; these can be expressed in cells and endogenous cellular proteins that copurify with the bait can be identified as putative interacting proteins using mass spectrometry. Control experiments can be used to limit false-positive results, but in many cases, there are still a surprising number of prey proteins that appear to copurify specifically with the bait. Here, we have identified one source of false-positive interactions in such studies. We have found that a combination of: 1) the variable sequence of the C-terminus of the bait with 2) a C-terminal valine “cloning scar” present in a commercially available ORF library, can in some cases create a peptide motif that results in the aberrant co-purification of endogenous cellular proteins. Control experiments may not identify false positives resulting from such artificial motifs, as aberrant binding depends on sequences that vary from one bait to another. It is possible that such cryptic protein binding might occur in other systems using affinity tagged proteins; this study highlights the importance of conducting careful follow-up studies where novel protein-protein interactions are suspected. PMID:25704442

Chemical applicability domain of the Local Lymph Node Assay (LLNA) for skin sensitisation potency. Part 3. Apparent discrepancies between LLNA and GPMT sensitisation potential: False positives or differences in sensitivity?

PubMed

Roberts, David W; Schultz, Terry W; Api, Anne Marie

2016-10-01

The Local Lymph Node Assay (LLNA) is the gold standard regulatory toxicology test for skin sensitisation along with the guinea pig maximisation test (GPMT). Compared with the GPMT, LLNA uses fewer animals, it is quantitative, and it gives a numerical prediction of potency. However several concerns have been raised with this assay, mainly related to false positives and false negatives. Over the years, many authors, including the developers of the assay, have presented cases where there have been discrepancies between the GMPT and LLNA results. Several theories have been put forward for these discrepancies, the main one being the "over-sensitivity" of the GPMT. This paper analyses the data from a systematic study, published in three papers from 2008 to 2011, covering several classes of chemicals, in particular unsaturated fatty acids, sugar surfactants and ethoxylated alcohols, with many cases of chemicals testing positive in the LLNA being negative in the GPMT. Based on consideration of reaction chemistry and structural alerts, it is concluded that these discrepancies are not LLNA false positives, but can be rationalised in terms of the different protocols of the assays. Copyright © 2016 Elsevier Inc. All rights reserved.

Ignoring Intermarker Linkage Disequilibrium Induces False-Positive Evidence of Linkage for Consanguineous Pedigrees when Genotype Data Is Missing for Any Pedigree Member

PubMed Central

Li, Bingshan; Leal, Suzanne M.

2008-01-01

Missing genotype data can increase false-positive evidence for linkage when either parametric or nonparametric analysis is carried out ignoring intermarker linkage disequilibrium (LD). Previously it was demonstrated by Huang et al. [1] that no bias occurs in this situation for affected sib-pairs with unrelated parents when either both parents are genotyped or genotype data is available for two additional unaffected siblings when parental genotypes are missing. However, this is not the case for autosomal recessive consanguineous pedigrees, where missing genotype data for any pedigree member within a consanguinity loop can increase false-positive evidence of linkage. False-positive evidence for linkage is further increased when cryptic consanguinity is present. The amount of false-positive evidence for linkage, and which family members aid in its reduction, is highly dependent on which family members are genotyped. When parental genotype data is available, the false-positive evidence for linkage is usually not as strong as when parental genotype data is unavailable. For a pedigree with an affected proband whose first-cousin parents have been genotyped, further reduction in the false-positive evidence of linkage can be obtained by including genotype data from additional affected siblings of the proband or genotype data from the proband's sibling-grandparents. For the situation, when parental genotypes are unavailable, false-positive evidence for linkage can be reduced by including genotype data from either unaffected siblings of the proband or the proband's married-in-grandparents in the analysis. PMID:18073490

p-hacking by post hoc selection with multiple opportunities: Detectability by skewness test?: Comment on Simonsohn, Nelson, and Simmons (2014).

PubMed

Ulrich, Rolf; Miller, Jeff

2015-12-01

Simonsohn, Nelson, and Simmons (2014) have suggested a novel test to detect p-hacking in research, that is, when researchers report excessive rates of "significant effects" that are truly false positives. Although this test is very useful for identifying true effects in some cases, it fails to identify false positives in several situations when researchers conduct multiple statistical tests (e.g., reporting the most significant result). In these cases, p-curves are right-skewed, thereby mimicking the existence of real effects even if no effect is actually present. (c) 2015 APA, all rights reserved).

Reduction of false-positive recalls using a computerized mammographic image feature analysis scheme

NASA Astrophysics Data System (ADS)

Tan, Maxine; Pu, Jiantao; Zheng, Bin

2014-08-01

The high false-positive recall rate is one of the major dilemmas that significantly reduce the efficacy of screening mammography, which harms a large fraction of women and increases healthcare cost. This study aims to investigate the feasibility of helping reduce false-positive recalls by developing a new computer-aided diagnosis (CAD) scheme based on the analysis of global mammographic texture and density features computed from four-view images. Our database includes full-field digital mammography (FFDM) images acquired from 1052 recalled women (669 positive for cancer and 383 benign). Each case has four images: two craniocaudal (CC) and two mediolateral oblique (MLO) views. Our CAD scheme first computed global texture features related to the mammographic density distribution on the segmented breast regions of four images. Second, the computed features were given to two artificial neural network (ANN) classifiers that were separately trained and tested in a ten-fold cross-validation scheme on CC and MLO view images, respectively. Finally, two ANN classification scores were combined using a new adaptive scoring fusion method that automatically determined the optimal weights to assign to both views. CAD performance was tested using the area under a receiver operating characteristic curve (AUC). The AUC = 0.793  ±  0.026 was obtained for this four-view CAD scheme, which was significantly higher at the 5% significance level than the AUCs achieved when using only CC (p = 0.025) or MLO (p = 0.0004) view images, respectively. This study demonstrates that a quantitative assessment of global mammographic image texture and density features could provide useful and/or supplementary information to classify between malignant and benign cases among the recalled cases, which may eventually help reduce the false-positive recall rate in screening mammography.

Non-invasive risk assessment of fetal sex chromosome aneuploidy through directed analysis and incorporation of fetal fraction.

PubMed

Hooks, J; Wolfberg, A J; Wang, E T; Struble, C A; Zahn, J; Juneau, K; Mohseni, M; Huang, S; Bogard, P; Song, K; Oliphant, A; Musci, T J

2014-05-01

To assess the performance of a directed chromosomal analysis approach in the prenatal evaluation of fetal sex chromosome aneuploidy. We analyzed 432 frozen maternal plasma samples obtained from patients prior to undergoing fetal diagnostic testing. The cohort included women greater than 18 years of age with a singleton pregnancy of greater than 10 weeks gestation. Samples were analyzed using a chromosome-selective approach (DANSR(TM) ) and a risk algorithm that incorporates fetal fraction (FORTE(TM) ). The cohort included 34 cases of sex chromosome aneuploidy. The assay correctly identified 26 of 27 (92.6%) cases of Monosomy X, one case of XXX, and all six cases of XXY. There were four false positive cases of sex chromosome aneuploidy among 380 euploid cases for an overall false positive rate of less than 1%. Analysis of the risk for sex chromosome aneuploidies can be accomplished with a targeted assay with high sensitivity. © 2014 John Wiley & Sons, Ltd.

The diagnostic significance of lactate dehydrogenase isoenzymes in urinary cytology.

PubMed Central

Nishikawa, A.; Tanaka, T.; Takeuchi, T.; Fujihiro, S.; Mori, H.

1991-01-01

Lactate dehydrogenase (LDH) isoenzyme distribution was examined in 106 urine samples being tested cytologically for evidence of bladder cancer; the samples were selected to have less than 20 leucocytes and erythrocytes per high power field and the LDH pattern determined by electrophoresis. The Papanicolaou stained-smears showed 68 negative, 17 suspicious and 21 positive. The LDH M-fraction of the urinary supernatant in cytologically positive cases was significantly greater than in negative cases, although the latter included a few false negative samples. Some of the false negatives gave positive results for the LDH M-fraction; these results suggest that the determination of LDH isoenzymes in the urine is useful in diagnosing urinary tract cancers, including early stage, and for follow-up of patients with bladder cancers after surgical resection. PMID:2039708

Application of the LDM algorithm to identify small lung nodules on low-dose MSCT scans

NASA Astrophysics Data System (ADS)

Zhao, Binsheng; Ginsberg, Michelle S.; Lefkowitz, Robert A.; Jiang, Li; Cooper, Cathleen; Schwartz, Lawrence H.

2004-05-01

In this work, we present a computer-aided detection (CAD) algorithm for small lung nodules on low-dose MSCT images. With this technique, identification of potential lung nodules is carried out with a local density maximum (LDM) algorithm, followed by reduction of false positives from the nodule candidates using task-specific 2-D/3-D features along with a knowledge-based nodule inclusion/exclusion strategy. Twenty-eight MSCT scans (40/80mAs, 120kVp, 5mm collimation/2.5mm reconstruction) from our lung cancer screening program that included at least one lung nodule were selected for this study. Two radiologists independently interpreted these cases. Subsequently, a consensus reading by both radiologists and CAD was generated to define a "gold standard". In total, 165 nodules were considered as the "gold standard" (average: 5.9 nodules/case; range: 1-22 nodules/case). The two radiologists detected 146 nodules (88.5%) and CAD detected 100 nodules (60.6%) with 8.7 false-positives/case. CAD detected an additional 19 nodules (6 nodules > 3mm and 13 nodules < 3mm) that had been missed by both radiologists. Preliminary results show that the CAD is capable of detecting small lung nodules with acceptable number of false-positives on low-dose MSCT scans and it can detect nodules that are otherwise missed by radiologists, though a majority are small nodules (< 3mm).

The management of isolated positive syphilis enzyme immunoassay results in HIV-negative patients attending a sexual health clinic.

PubMed

Thorley, Nicola; Adebayo, Michael; Smit, Erasmus; Radcliffe, Keith

2016-08-01

An unconfirmed positive treponemal enzyme immunoassay (enzyme immunoassay positive, Treponema pallidum particle agglutination negative and rapid plasma reagin negative) presents a clinical challenge to distinguish early syphilis infection from false-positive results. These cases are referred for syphilis line assay (INNO-LIA) and recalled for repeat syphilis serology. We performed a retrospective audit to establish the proportion of HIV-negative cases with unconfirmed positive enzyme immunoassay results, the proportion of these cases that received an INNO-LIA test and repeat syphilis serology testing and reviewed the clinical outcomes; 0.35% (80/22687) cases had an unconfirmed positive treponemal enzyme immunoassay result. Repeat syphilis serology was performed in 80% (64/80) cases, but no additional cases of syphilis were identified. Eighty-eight per cent (70/80) received an INNO-LIA test; 14% (5/37) unconfirmed enzyme immunoassay-positive cases with no prior history of syphilis were confirmed on INNO-LIA assay, supporting a diagnosis of latent syphilis. As a confirmatory treponemal test, the INNO-LIA assay may be more useful than repeat syphilis serological testing. © The Author(s) 2016.

Comparison of 68Ga-DOTANOC PET/CT and contrast-enhanced CT in localisation of tumours in ectopic ACTH syndrome

PubMed Central

Jadhav, Swati S; Lila, Anurag R; Kasaliwal, Rajeev; Khare, Shruti; Yerawar, Chaitanya G; Hira, Priya; Phadke, Uday; Shah, Hina; Lele, Vikram R; Malhotra, Gaurav; Bandgar, Tushar; Shah, Nalini S

2016-01-01

Background Localising ectopic adrenocorticotrophic hormone (ACTH) syndrome (EAS) tumour source is challenging. Somatostatin receptor-based PET imaging has shown promising results, but the data is limited to case reports and small case series. We reviewed here the performance of 68Ga-DOTANOC positron emission tomography (PET)/computed tomography (CT) and contrast-enhanced CT (CECT) in our cohort of 12 consecutive EAS patients. Materials and methods Retrospective data analysis of 12 consecutive patients of EAS presenting to a single tertiary care centre in a period between January 2013 and December 2014 was done. CECT and 68Ga-DOTANOC PET/CT were reported (blinded) by an experienced radiologist and a nuclear medicine physician, respectively. The performance of CECT and 68Ga-DOTANOC PET/CT was compared. Results Tumours could be localised in 11 out of 12 patients at initial presentation (overt cases), whereas in one patient, tumour remained occult. Thirteen lesions were identified in 11 patients as EAS source (true positives). CECT localised 12 out of these 13 lesions (sensitivity 92.3%) and identified five false-positive lesions (positive predictive value (PPV) 70.5%). Compared with false-positive lesions, true-positive lesions had greater mean contrast enhancement at 60s (33.2 vs 5.6 Hounsfield units (HU)). 68Ga-DOTANOC PET/CT was able to identify 9 out of 13 lesions (sensitivity 69.2%) and reported no false-positive lesions (PPV 100%). Conclusion CECT remains the first-line investigation in localisation of EAS. The contrast enhancement pattern on CECT can further aid in characterisation of the lesions. 68Ga-DOTANOC PET/CT can be added to CECT, to enhance positive prediction of the suggestive lesions. PMID:27006371

False-positive cerebrospinal fluid cryptococcus antigen in Libman-Sacks endocarditis.

PubMed

Isseh, Iyad N; Bourgi, Kassem; Nakhle, Asaad; Ali, Mahmoud; Zervos, Marcus J

2016-12-01

Cryptococcus meningoencephalitis is a serious opportunistic infection associated with high morbidity and mortality in immunocompromised hosts, particularly patients with advanced AIDS disease. The diagnosis is established through cerebrospinal fluid (CSF) cryptococcus antigen detection and cultures. Cryptococcus antigen testing is usually the initial test of choice due its high sensitivity and specificity along with the quick availability of the results. We hereby report a case of a false-positive CSF cryptococcus antigen assay in a patient with systemic lupus erythematosus presenting with acute confusion. While initial CSF evaluation revealed a positive cryptococcus antigen assay, the patient's symptoms were inconsistent with cryptococcus meningoencephalitis. A repeat CSF evaluation, done 3 days later, revealed a negative CSF cryptococcus antigen assay. Given the patient's active lupus disease and the elevated antinuclear antibody titers, we believe that the initial positive result was a false positive caused by interference from autoantibodies.

29 CFR 1904.11 - Recording criteria for work-related tuberculosis cases.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 5 2010-07-01 2010-07-01 false Recording criteria for work-related tuberculosis cases... Forms and Recording Criteria § 1904.11 Recording criteria for work-related tuberculosis cases. (a) Basic... tuberculosis (TB), and that employee subsequently develops a tuberculosis infection, as evidenced by a positive...

29 CFR 1904.11 - Recording criteria for work-related tuberculosis cases.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 29 Labor 5 2013-07-01 2013-07-01 false Recording criteria for work-related tuberculosis cases... Forms and Recording Criteria § 1904.11 Recording criteria for work-related tuberculosis cases. (a) Basic... tuberculosis (TB), and that employee subsequently develops a tuberculosis infection, as evidenced by a positive...

29 CFR 1904.11 - Recording criteria for work-related tuberculosis cases.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 5 2012-07-01 2012-07-01 false Recording criteria for work-related tuberculosis cases... Forms and Recording Criteria § 1904.11 Recording criteria for work-related tuberculosis cases. (a) Basic... tuberculosis (TB), and that employee subsequently develops a tuberculosis infection, as evidenced by a positive...

29 CFR 1904.11 - Recording criteria for work-related tuberculosis cases.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 5 2014-07-01 2014-07-01 false Recording criteria for work-related tuberculosis cases... Forms and Recording Criteria § 1904.11 Recording criteria for work-related tuberculosis cases. (a) Basic... tuberculosis (TB), and that employee subsequently develops a tuberculosis infection, as evidenced by a positive...

29 CFR 1904.11 - Recording criteria for work-related tuberculosis cases.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 5 2011-07-01 2011-07-01 false Recording criteria for work-related tuberculosis cases... Forms and Recording Criteria § 1904.11 Recording criteria for work-related tuberculosis cases. (a) Basic... tuberculosis (TB), and that employee subsequently develops a tuberculosis infection, as evidenced by a positive...

[The ultrasonic diagnosis of jaundice. 199 cases (author's transl)].

PubMed

Weill, F; Marmier, A; Paronneau, P; Zeltner, F; Charton, M N

1978-11-25

Thank to a thorough ultrasonographic analysis of biliary tree ("shotgun sign"), liver and pancreas, a positive diagnosis of obstruction was carried out in 92% of cases. The success rate in diagnosis of level of obstruction was also 92%. Aetiologic diagnosis was successful in 61% of cases only (almost 100% in jaundices of pancreatic origine). No false positive diagnosis of obstruction was made in non-obstructive jaundice. This enabled to carry out instrumental cholangiography (i.e. "skinny" needle percutaneous cholangiography, and ERC) only in case of clinical, biological and sonographic discrepancies, or in hilar obstructions.

Evaluation of the Components of the North Carolina Syndromic Surveillance System Heat Syndrome Case Definition.

PubMed

Harduar Morano, Laurel; Waller, Anna E

To improve heat-related illness surveillance, we evaluated and refined North Carolina's heat syndrome case definition. We analyzed North Carolina emergency department (ED) visits during 2012-2014. We evaluated the current heat syndrome case definition (ie, keywords in chief complaint/triage notes or International Classification of Diseases, Ninth Revision, Clinical Modification [ ICD-9-CM] codes) and additional heat-related inclusion and exclusion keywords. We calculated the positive predictive value and sensitivity of keyword-identified ED visits and manually reviewed ED visits to identify true positives and false positives. The current heat syndrome case definition identified 8928 ED visits; additional inclusion keywords identified another 598 ED visits. Of 4006 keyword-identified ED visits, 3216 (80.3%) were captured by 4 phrases: "heat ex" (n = 1674, 41.8%), "overheat" (n = 646, 16.1%), "too hot" (n = 594, 14.8%), and "heatstroke" (n = 302, 7.5%). Among the 267 ED visits identified by keyword only, a burn diagnosis or the following keywords resulted in a false-positive rate >95%: "burn," "grease," "liquid," "oil," "radiator," "antifreeze," "hot tub," "hot spring," and "sauna." After applying the revised inclusion and exclusion criteria, we identified 9132 heat-related ED visits: 2157 by keyword only, 5493 by ICD-9-CM code only, and 1482 by both (sensitivity = 27.0%, positive predictive value = 40.7%). Cases identified by keywords were strongly correlated with cases identified by ICD-9-CM codes (rho = .94, P < .001). Revising the heat syndrome case definition through the use of additional inclusion and exclusion criteria substantially improved the accuracy of the surveillance system. Other jurisdictions may benefit from refining their heat syndrome case definition.

Rapid Identification of Laboratory Contamination with Mycobacterium tuberculosis Using Variable Number Tandem Repeat Analysis

PubMed Central

Gascoyne-Binzi, Deborah M.; Barlow, Rachael E. L.; Frothingham, Richard; Robinson, Grant; Collyns, Timothy A.; Gelletlie, Ruth; Hawkey, Peter M.

2001-01-01

Compared with solid media, broth-based mycobacterial culture systems have increased sensitivity but also have higher false-positive rates due to cross-contamination. Systematic strain typing is rarely undertaken because the techniques are technically demanding and the data are difficult to organize. Variable number tandem repeat (VNTR) analysis by PCR is rapid and reproducible. The digital profile is easily manipulated in a database. We undertook a retrospective study of Mycobacterium tuberculosis isolates collected over an 18-month period following the introduction of the BACTEC MGIT 960 system. VNTR allele profiles were determined with early positive broth cultures and entered into a database with the specimen processing date and other specimen data. We found 36 distinct VNTR profiles in cultures from 144 patients. Three common VNTR profiles accounted for 45% of true-positive cases. By combining VNTR results with specimen data, we identified nine cross-contamination incidents, six of which were previously unsuspected. These nine incidents resulted in 34 false-positive cultures for 29 patients. False-positive cultures were identified for three patients who had previously been culture positive for tuberculosis and were receiving treatment. Identification of cross-contamination incidents requires careful documentation of specimen data and good communication between clinical and laboratory staff. Automated broth culture systems should be supplemented with molecular analysis to identify cross-contamination events. VNTR analysis is reproducible and provides timely results when applied to early positive broth cultures. This method should ensure that patients are not placed on unnecessary tuberculosis therapy or that cases are not falsely identified as treatment failures. In addition, areas where existing procedures may be improved can be identified. PMID:11136751

Direct versus indirect molecular diagnosis of fragile X mental retardation in 40 German families at risk.

PubMed

Knobloch, O; Pelz, F; Wick, U; Nelson, D L; Zoll, B

1993-03-01

In order to test whether the direct molecular diagnostic approach for fragile X mental retardation (Martin-Bell syndrome, MBS) really makes diagnosis of this disease more precise, we evaluated the results of direct diagnosis in 40 German families at risk together with the results of an earlier study with closely linked flanking markers in the same families. Of 84 men analysed, 43 showed clinical signs. In 39 of these affected men the disease could be confirmed by direct diagnosis. Compared to cytogenetic data, one man was false negative and two were false positive. Two men, whose status could not be determined by means of RFLP data, proved to be normal transmitting males (NTMs). However, the possibility of being an NTM had to be rejected in one case on RFLP data. Fragile X syndrome could be confirmed in 10 of the 13 women with clinical signs. Compared to cytogenetic data there were three cases of false negative results and one of false positive. All 36 obligate carrier women were detected by the direct approach. In addition, 22 women were newly identified as normal transmitting females (NTFs), among them one woman who could not be identified by cytogenetic means or by analysis with closely linked markers. These findings are discussed in view of the relative reliability of the three diagnostic approaches to MBS. Special attention is drawn to the significance of false negative and false positive results in direct diagnosis.

[False positive of DUPAN-2 caused by IgM-human anti mouse antibody].

PubMed

Abe, Masaki; Hyoki, Miyuki; Abe, Ikurou; Kaito, Ken; Takagi, Ichirou

2012-11-01

We investigated a case in our experience presenting false-positive for DUPAN-2 by IgM-human anti mouse antibody (HAMA). A female aged 40s has been treated in our hospital from 2003. Her serum level of DUPAN-2 in 2005 and 2006 were 110 U/mL and 140 U/mL respectively. While this level was increased to 770 U/ml in 2007, and kept in the higher level so far. Around years of 2007, no meaning changes was detected by radiological and laboratory tests, and there was no significant change in her clinical signs and symptoms and medications. The elevation of DUPAN-2 was thought as a false-positive phenomenon and the mechanism was investigated. As results, no dilution lineality was found, and absorption test showed a 95% reduction of DUPAN-2 levels not by IgG and IgA, but IgM-specific antiserum. Dithiothreitoldeacylation test with neuraminidase, and absorption test with HBR-1, IIR, and mouse IgM serum, it was suggested that the IgM with HAMA activity of the patient reacted with mouse monoclonal antibodies in reagents. Moreover, the HPLC-eluted fraction of DUPAN-2 of this patients was detected in the fraction of IgM, which as different from that of a control pancreatic cancer patient. Above these data, elevation of DUPAN-2 in this patient was a false positive phenomenon by IgM-HAMA reacting with mouse monoclonal antibodies in reagents. Although there are few reported cases of false positive phenomenon in DUPAN-2 measurement, we have to pay attention to such phenomenon when detecting an unlikely higher levels that could not be explained by clinical information.

Analysis of sentinel node positivity in primary cutaneous melanoma: an 8-year single institution experience.

PubMed

Joyce, K M; McInerney, N M; Piggott, R P; Martin, F; Jones, D M; Hussey, A J; Kerin, M J; Kelly, J L; Regan, P J

2017-11-01

Sentinel lymph node biopsy (SLNB) is a standard method for determining the pathologic status of the regional lymph nodes. The aim of our study was to determine the incidence and clinicopathologic factors predictive of SLN positivity, and to evaluate the prognostic importance of SLNB in patients with cutaneous melanoma. We performed a retrospective analysis of a prospectively maintained database of all patients who underwent SLNB for primary melanoma at our institution from 2005 to 2012. Statistical analysis was performed using χ 2 and Fischer exact test. In total, 318 patients underwent SLNB, of which 65 were for thin melanoma (≤1 mm). There were 36 positive SLNB, 278 negative SLNB and in four cases the SLN was not located. The incidence rate for SLNB was 11.3% overall and 1.5% in thin melanomas alone. Statistical analysis identified Breslow thickness >1 mm (P = 0.006), Clark level ≥ IV (P = 0.004) and age <75 years (P = 0.035) as the strongest predictors of SLN positivity. Our overall false negativity rate was 20% (9/45) with one case of false-negative SLNB in thin melanomas. Breslow thickness of the primary tumour remains the strongest predictor of SLN positivity. Our findings point to a possible limited role for SLNB in thin melanoma due to its low positivity rate, associated false-negative rate and related morbidity.

Clinical significance of FDG-PET/CT at the postoperative surveillance in the breast cancer patients.

PubMed

Jung, Na Young; Yoo, Ie Ryung; Kang, Bong Joo; Kim, Sung Hun; Chae, Byung Joo; Seo, Ye Young

2016-01-01

We evaluated the clinical role of [(18)F]-2-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) compared with conventional imaging (CI) to detect locoregional recurrence or distant metastasis during postoperative surveillance of patients with breast cancer. We included 1,819 examinations of 1,161 patients, who underwent FDG-PET/CT and CI, including mammography, breast ultrasound, whole-body bone scintigraphy, and chest radiography for postoperative surveillance. All patients had a history of surgery with or without adjuvant treatment due to more than stage II breast cancer between November 2003 and November 2009. We evaluated the diagnostic performance of CI, FDG-PET/CT, and combined CI and FDG-PET/CT for detecting locoregional recurrence, distant metastasis, and incidental cancer. We also analyzed false-positive and false-negative results in both FDG-PET/CT and CI. Sensitivity, specificity, positive predictive value, and negative predictive value of CI were 75.4, 98.7, 93.4, and 94.3 %. Those of FDG-PET/CT were 97.5, 98.8, 95.4, and 99.4 %. Those of the combined results were 98.6, 98.2, 96.7, and 99.7 %. Sensitivity of FDG-PET/CT was significantly higher than that of CI (P < 0.05). Sensitivity of combined CI and FDG-PET/CT results improved, but they were not significantly different from those of FDG-PET/CT alone (P = 0.43). Seventeen false-positive and nine false-negative cases were detected with FDG-PET/CT, and 19 false-positive and 88 false-negative cases were detected with CI. FDG-PET/CT is considered as an acceptable diagnostic imaging modality for postoperative surveillance of patients with breast cancer.

Newborn Hearing Screening and Early Diagnostic in the NICU

PubMed Central

Colella-Santos, Maria Francisca; Hein, Thaís Antonelli Diniz; de Souza, Gabriele Libano; do Amaral, Maria Isabel Ramos; Casali, Raquel Leme

2014-01-01

The aim was to describe the outcome of neonatal hearing screening (NHS) and audiological diagnosis in neonates in the NICU. The sample was divided into Group I: neonates who underwent NHS in one step and Group II: neonates who underwent a test and retest NHS. NHS procedure was automated auditory brainstem response. NHS was performed in 82.1% of surviving neonates. For GI, referral rate was 18.6% and false-positive was 62.2% (normal hearing in the diagnostic stage). In GII, with retest, referral rate dropped to 4.1% and false-positive to 12.5%. Sensorineural hearing loss was found in 13.2% of infants and conductive in 26.4% of cases. There was one case of auditory neuropathy spectrum (1.9%). Dropout rate in whole process was 21.7% for GI and 24.03% for GII. We concluded that it was not possible to perform universal NHS in the studied sample or, in many cases, to apply it within the first month of life. Retest reduced failure and false-positive rate and did not increase evasion, indicating that it is a recommendable step in NHS programs in the NICU. The incidence of hearing loss was 2.9%, considering sensorineural hearing loss (0.91%), conductive (1.83%) and auditory neuropathy spectrum (0.19%). PMID:24999481

A Study of False-Positive and False-Negative Error Rates in Cartridge Case Comparisons

DTIC Science & Technology

2014-04-07

materials for the study, in particular Vicki Sieve. 3 Abstract: This report provides the details for a study designed to...participate in ASCLD were provided with 15 sets of 3 known + 1 unknown cartridge cases fired from a collection of 25 new Ruger SR9 handguns . The...answer sheet allowing for the AFTE range of conclusions, and return shipping materials . They were also asked to assess how many of the 3 knowns were

The introduction of the absolute risk for the detection of fetal aneuploidies in the first-trimester screening.

PubMed

Padula, Francesco; Laganà, Antonio Simone; Vitale, Salvatore Giovanni; D'Emidio, Laura; Coco, Claudio; Giannarelli, Diana; Cariola, Maria; Favilli, Alessandro; Giorlandino, Claudio

2017-05-01

Maternal age is a crucial factor in fetal aneuploidy screening, resulting in an increased rate of false-positive cases in older women and false-negative cases in younger women. The absolute risk (AR) is the simplest way to eliminate the background maternal age risk, as it represents the amount of improvement of the combined risk from the maternal background risk. The aim of this work is to assess the performance of the AR in the combined first-trimester screening for aneuploidies. A retrospective validation of the AR in the combined first-trimester screening for fetal aneuploidies, in an unselected population at Altamedica Fetal-Maternal Medical Center in Rome, between March 2007 and December 2008. Of 3845 women included in the study, we had a complete follow-up on 2984. We evaluated that an AR < 3 would individuate 22 of 23 cases of aneuploidy with a detection rate of 95.7% (95%CI 87.3-100), a false-positive rate of 8.7% (95%CI 7.7-9.7) and a false-negative rate of 4.3% (95%CI 0-12.7). In our study, the AR ameliorates the detection rate for aneuploidy. Further research and a prospective study on a larger population would help us to improve the AR in detecting most cases of aneuploidy.

Skin testing for immediate hypersensitivity to corticosteroids: a case series and literature review.

PubMed

Baker, A; Empson, M; The, R; Fitzharris, P

2015-03-01

Immediate hypersensitivity to corticosteroids is reported to occur with an incidence of 0.1%. The largest previous case series reporting corticosteroid skin testing has seven patients. We identified 23 patients (mean age 50 years, 65% female) from Auckland City Hospital who underwent skin testing (ST) for suspected corticosteroid hypersensitivity between July 2005 and April 2012. We performed a retrospective clinical case note review detailing clinical history of reaction, skin test results and subsequent management. Most patients (21/23) had a standard panel of testing with prednisolone, triamcinolone, methylprednisolone, hydrocortisone and dexamethasone. Skin tests used a 10% steroid stock concentration for skin prick tests (SPT) and dilutions of 1 : 1000, 1 : 100 and 1 : 10 for subsequent intradermal testing. A weal 3 mm greater than the negative control was considered positive. A total of 23 patients were identified who had skin testing for suspected acute hypersensitivity to corticosteroids, eight of which had a history of anaphylaxis. From 28 reactions (in 23 patients), the most common route of administration was intra-articular (13), followed by oral (7), intravenous (3) and other (5). Skin tests were positive in 8/23 patients, and 7/8 of these patients had a history of corticosteroid-associated anaphylaxis. Skin tests were positive at either the skin prick test or intradermal stages. There was evidence suggesting clinical and skin test cross-reactivity between corticosteroids in one patient. One patient had a positive skin test, but negative oral challenge suggesting the skin test was false positive. Skin tests were negative in 15/23 patients. One patient had a negative prednisolone skin test and positive unblinded oral challenge, suggesting a false-negative skin test. Skin testing can provide sufficient evidence to diagnose allergy in patients with a clear history of immediate hypersensitivity to corticosteroids such as anaphylaxis. Both skin prick and intradermal tests should be used. There is evidence of cross-reactivity between steroids, so a panel is recommended. False-positive and false-negative reactions do occur; however, the frequency is unknown. Challenge remains the only definitive way to demonstrate a safe alternative to use. As the largest case series described, this article provides new evidence for the interpretation of skin tests when investigating possible immediate hypersensitivity to corticosteroids. © 2014 John Wiley & Sons Ltd.

Prenatal Ultrasound Screening: False Positive Soft Markers May Alter Maternal Representations and Mother-Infant Interaction

PubMed Central

Viaux-Savelon, Sylvie; Dommergues, Marc; Rosenblum, Ouriel; Bodeau, Nicolas; Aidane, Elizabeth; Philippon, Odile; Mazet, Philippe; Vibert-Guigue, Claude; Vauthier-Brouzes, Danièle; Feldman, Ruth; Cohen, David

2012-01-01

Background In up to 5% of pregnancies, ultrasound screening detects a “soft marker” (SM) that places the foetus at risk for a severe abnormality. In most cases, prenatal diagnostic work-up rules out a severe defect. We aimed to study the effects of false positive SM on maternal emotional status, maternal representations of the infant, and mother-infant interaction. Methodology and Principal Findings Utilizing an extreme-case prospective case control design, we selected from a group of 244 women undergoing ultrasound, 19 pregnant women whose foetus had a positive SM screening and a reassuring diagnostic work up, and 19 controls without SM matched for age and education. In the third trimester of pregnancy, within one week after delivery, and 2 months postpartum, we assessed anxiety, depression, and maternal representations. Mother-infant interactions were videotaped during feeding within one week after delivery and again at 2 months postpartum and coded blindly using the Coding Interactive Behavior (CIB) scales. Anxiety and depression scores were significantly higher at all assessment points in the SM group. Maternal representations were also different between SM and control groups at all study time. Perturbations to early mother-infant interactions were observed in the SM group. These dyads showed greater dysregulation, lower maternal sensitivity, higher maternal intrusive behaviour and higher infant avoidance. Multivariate analysis showed that maternal representation and depression at third trimester predicted mother-infant interaction. Conclusion False positive ultrasound screenings for SM are not benign and negatively affect the developing maternal-infant attachment. Medical efforts should be directed to minimize as much as possible such false diagnoses, and to limit their psychological adverse consequences. PMID:22292077

An investigation into false-negative transthoracic fine needle aspiration and core biopsy specimens.

PubMed

Minot, Douglas M; Gilman, Elizabeth A; Aubry, Marie-Christine; Voss, Jesse S; Van Epps, Sarah G; Tuve, Delores J; Sciallis, Andrew P; Henry, Michael R; Salomao, Diva R; Lee, Peter; Carlson, Stephanie K; Clayton, Amy C

2014-12-01

Transthoracic fine needle aspiration (TFNA)/core needle biopsy (CNB) under computed tomography (CT) guidance has proved useful in the assessment of pulmonary nodules. We sought to determine the TFNA false-negative (FN) rate at our institution and identify potential causes of FN diagnoses. Medical records were reviewed from 1,043 consecutive patients who underwent CT-guided TFNA with or without CNB of lung nodules over a 5-year time period (2003-2007). Thirty-seven FN cases of "negative" TFNA/CNB with malignant outcome were identified with 36 cases available for review, of which 35 had a corresponding CNB. Cases were reviewed independently (blinded to original diagnosis) by three pathologists with 15 age- and sex-matched positive and negative controls. Diagnosis (i.e., nondiagnostic, negative or positive for malignancy, atypical or suspicious) and qualitative assessments were recorded. Consensus diagnosis was suspicious or positive in 10 (28%) of 36 TFNA cases and suspicious in 1 (3%) of 35 CNB cases, indicating potential interpretive errors. Of the 11 interpretive errors (including both suspicious and positive cases), 8 were adenocarcinomas, 1 squamous cell carcinoma, 1 metastatic renal cell carcinoma, and 1 lymphoma. The remaining 25 FN cases (69.4%) were considered sampling errors and consisted of 7 adenocarcinomas, 3 nonsmall cell carcinomas, 3 lymphomas, 2 squamous cell carcinomas, and 2 renal cell carcinomas. Interpretive and sampling error cases were more likely to abut the pleura, while histopathologically, they tended to be necrotic and air-dried. The overall FN rate in this patient cohort is 3.5% (1.1% interpretive and 2.4% sampling errors). © 2014 Wiley Periodicals, Inc.

Quantification of human epidermal growth factor receptor 2 immunohistochemistry using the Ventana Image Analysis System: correlation with gene amplification by fluorescence in situ hybridization: the importance of instrument validation for achieving high (>95%) concordance rate.

PubMed

Dennis, Jake; Parsa, Rezvaneh; Chau, Donnie; Koduru, Prasad; Peng, Yan; Fang, Yisheng; Sarode, Venetia Rumnong

2015-05-01

The use of computer-based image analysis for scoring human epidermal growth factor receptor 2 (HER2) immunohistochemistry (IHC) has gained a lot of interest recently. We investigated the performance of the Ventana Image Analysis System (VIAS) in HER2 quantification by IHC and its correlation with fluorescence in situ hybridization (FISH). We specifically compared the 3+ IHC results using the manufacturer's machine score cutoffs versus laboratory-defined cutoffs with the FISH assay. Using the manufacturer's 3+ cutoff (VIAS score; 2.51 to 3.5), 181/536 (33.7%) were scored 3+, and FISH was positive in 147/181 (81.2%), 2 (1.1%) were equivocal, and 32 (17.6%) were FISH (-). Using the laboratory-defined 3+ cutoff (VIAS score 3.5), 52 (28.7%) cases were downgraded to 2+, of which 29 (55.7%) were FISH (-), and 23 (44.2%) were FISH (+). With the revised cutoff, there were improvements in the concordance rate from 89.1% to 97.0% and in the positive predictive value from 82.1% to 97.6%. The false-positive rate for 3+ decreased from 9.0% to 0.8%. Six of 175 (3.4%) IHC (-) cases were FISH (+). Three cases with a VIAS score 3.5 showed polysomy of chromosome 17. In conclusion, the VIAS may be a valuable tool for assisting pathologists in HER2 scoring; however, the positive cutoff defined by the manufacturer is associated with a high false-positive rate. This study highlights the importance of instrument validation/calibration to reduce false-positive results.

Evaluation of the Architect HIV Ag/Ab Combo Assay in a low-prevalence setting: The role of samples with a low S/CO ratio.

PubMed

Alonso, Roberto; Pérez-García, Felipe; Gijón, Paloma; Collazos, Ana; Bouza, Emilio

2018-06-01

The Architect HIV Ag/Ab Combo Assay, a fourth-generation ELISA, has proven to be highly reliable for the diagnosis of HIV infection. However, its high sensitivity may lead to false-positive results. To evaluate the diagnostic performance of Architect in a low-prevalence population and to assess the role of the sample-to-cutoff ratio (S/CO) in reducing the frequency of false-positive results. We conducted a retrospective study of samples analyzed by Architect between January 2015 and June 2017. Positive samples were confirmed by immunoblot (RIBA) or nucleic acid amplification tests (NAATs). Different S/CO thresholds (1, 2.5, 10, 25, and 100) were analyzed to determine sensitivity, specificity, and negative and positive predictive values (NPV, PPV). ROC analysis was used to determine the optimal S/CO. A total of 69,471 samples were analyzed. 709 (1.02%) were positive by Architect. Of these, 63 (8.89%) were false-positive results. Most of them (93.65%) were in samples with S/CO < 100. However, most confirmations by NAATs (12 out of 19 cases) were also recorded for these samples. The optimal S/CO was 2.5, which provided the highest area under the ROC curve (0.9998) and no false-negative results. With this S/CO, sensitivity and specificity were 100.0%, and PPV and NPV were 95.8% and 100.0%, respectively. In addition, the frequency of false-positive results decreased significantly to 4.15%. Although Architect generates a relatively high number of false-positive results, raising the S/CO limit too much to increase specificity can lead to false-negative results, especially in newly infected individuals. Copyright © 2018 Elsevier B.V. All rights reserved.

Prehospital Acute ST-Elevation Myocardial Infarction Identification in San Diego: A Retrospective Analysis of the Effect of a New Software Algorithm.

PubMed

Coffey, Christanne; Serra, John; Goebel, Mat; Espinoza, Sarah; Castillo, Edward; Dunford, James

2018-05-03

A significant increase in false positive ST-elevation myocardial infarction (STEMI) electrocardiogram interpretations was noted after replacement of all of the City of San Diego's 110 monitor-defibrillator units with a new brand. These concerns were brought to the manufacturer and a revised interpretive algorithm was implemented. This study evaluated the effects of a revised interpretation algorithm to identify STEMI when used by San Diego paramedics. Data were reviewed 6 months before and 6 months after the introduction of a revised interpretation algorithm. True-positive and false-positive interpretations were identified. Factors contributing to an incorrect interpretation were assessed and patient demographics were collected. A total of 372 (234 preimplementation, 138 postimplementation) cases met inclusion criteria. There was a significant reduction in false positive STEMI (150 preimplementation, 40 postimplementation; p < 0.001) after implementation. The most common factors resulting in false positive before implementation were right bundle branch block, left bundle branch block, and atrial fibrillation. The new algorithm corrected for these misinterpretations with most postimplementation false positives attributed to benign early repolarization and poor data quality. Subsequent follow-up at 10 months showed maintenance of the observed reduction in false positives. This study shows that introducing a revised 12-lead interpretive algorithm resulted in a significant reduction in the number of false positive STEMI electrocardiogram interpretations in a large urban emergency medical services system. Rigorous testing and standardization of new interpretative software is recommended before introduction into a clinical setting to prevent issues resulting from inappropriate cardiac catheterization laboratory activations. Copyright © 2018 Elsevier Inc. All rights reserved.

Evaluation of surveillance case definition in the diagnosis of leptospirosis, using the Microscopic Agglutination Test: a validation study.

PubMed

Dassanayake, Dinesh L B; Wimalaratna, Harith; Agampodi, Suneth B; Liyanapathirana, Veranja C; Piyarathna, Thibbotumunuwe A C L; Goonapienuwala, Bimba L

2009-04-22

Leptospirosis is endemic in both urban and rural areas of Sri Lanka and there had been many out breaks in the recent past. This study was aimed at validating the leptospirosis surveillance case definition, using the Microscopic Agglutination Test (MAT). The study population consisted of patients with undiagnosed acute febrile illness who were admitted to the medical wards of the Teaching Hospital Kandy, from 1st July 2007 to 31st July 2008. The subjects were screened to diagnose leptospirosis according to the leptospirosis case definition. MAT was performed on blood samples taken from each patient on the 7th day of fever. Leptospirosis case definition was evaluated in regard to sensitivity, specificity and predictive values, using a MAT titre >or= 1:800 for confirming leptospirosis. A total of 123 patients were initially recruited of which 73 had clinical features compatible with the surveillance case definition. Out of the 73 only 57 had a positive MAT result (true positives) leaving 16 as false positives. Out of the 50 who didn't have clinical features compatible with the case definition 45 had a negative MAT as well (true negatives), therefore 5 were false negatives. Total number of MAT positives was 62 out of 123. According to these results the test sensitivity was 91.94%, specificity 73.77%, positive predictive value and negative predictive values were 78.08% and 90% respectively. Diagnostic accuracy of the test was 82.93%. This study confirms that the surveillance case definition has a very high sensitivity and negative predictive value with an average specificity in diagnosing leptospirosis, based on a MAT titre of >or= 1: 800.

Fetal sex chromosome testing by maternal plasma DNA sequencing: clinical laboratory experience and biology.

PubMed

Bianchi, Diana W; Parsa, Saba; Bhatt, Sucheta; Halks-Miller, Meredith; Kurtzman, Kathryn; Sehnert, Amy J; Swanson, Amy

2015-02-01

To describe the clinical experience with noninvasive prenatal testing for fetal sex chromosomes using sequencing of maternal plasma cell-free DNA in a commercial laboratory. A noninvasive prenatal testing laboratory data set was examined for samples in which fetal sex chromosomes were reported. Available clinical outcomes were reviewed. Of 18,161 samples with sex chromosome results, no sex chromosome aneuploidy was detected in 98.9% and the fetal sex was reported as XY (9,236) or XX (8,721). In 4 of 32 cases in which the fetal sex was reportedly discordant between noninvasive prenatal testing and karyotype or ultrasonogram, a potential biological reason for the discordance exists, including two cases of documented co-twin demise, one case of a maternal kidney transplant from a male donor, and one case of fetal ambiguous genitalia. In the remaining 204 samples (1.1%), one of four sex chromosome aneuploidies (monosomy X, XXX, XXY, or XYY) was detected. The frequency of false positive results for sex chromosome aneuploidies is a minimum of 0.26% and a maximum of 1.05%. All but one of the discordant sex chromosome aneuploidy results involved the X chromosome. In two putative false-positive XXX cases, maternal XXX was confirmed by karyotype. For the false-positive cases, mean maternal age was significantly higher in monosomy X (P<.001) and lower in XXX (P=.008). Noninvasive prenatal testing results for sex chromosome aneuploidy can be confounded by maternal or fetal biological phenomena. When a discordant noninvasive prenatal testing result is encountered, resolution requires additional maternal history, detailed fetal ultrasonography, and determination of fetal and possibly maternal karyotypes.

Local connected fractal dimension analysis in gill of fish experimentally exposed to toxicants.

PubMed

Manera, Maurizio; Giari, Luisa; De Pasquale, Joseph A; Sayyaf Dezfuli, Bahram

2016-06-01

An operator-neutral method was implemented to objectively assess European seabass, Dicentrarchus labrax (Linnaeus, 1758) gill pathology after experimental exposure to cadmium (Cd) and terbuthylazine (TBA) for 24 and 48h. An algorithm-derived local connected fractal dimension (LCFD) frequency measure was used in this comparative analysis. Canonical variates (CVA) and linear discriminant analysis (LDA) were used to evaluate the discrimination power of the method among exposure classes (unexposed, Cd exposed, TBA exposed). Misclassification, sensitivity and specificity, both with original and cross-validated cases, were determined. LCFDs frequencies enhanced the differences among classes which were visually selected after their means, respective variances and the differences between Cd and TBA exposed means, with respect to unexposed mean, were analyzed by scatter plots. Selected frequencies were then scanned by means of LDA, stepwise analysis, and Mahalanobis distance to detect the most discriminative frequencies out of ten originally selected. Discrimination resulted in 91.7% of cross-validated cases correctly classified (22 out of 24 total cases), with sensitivity and specificity, respectively, of 95.5% (1 false negative with respect to 21 really positive cases) and 75% (1 false positive with respect to 3 really negative cases). CVA with convex hull polygons ensured prompt, visually intuitive discrimination among exposure classes and graphically supported the false positive case. The combined use of semithin sections, which enhanced the visual evaluation of the overall lamellar structure; of LCFD analysis, which objectively detected local variation in complexity, without the possible bias connected to human personnel; and of CVA/LDA, could be an objective, sensitive and specific approach to study fish gill lamellar pathology. Furthermore this approach enabled discrimination with sufficient confidence between exposure classes or pathological states and avoided misdiagnosis. Copyright © 2016 Elsevier B.V. All rights reserved.

Clinical use of MRI for the evaluation of acute appendicitis during pregnancy.

PubMed

Patel, Darshan; Fingard, Jordan; Winters, Sean; Low, Gavin

2017-07-01

The purpose of this study was to determine the diagnostic accuracy of MRI for detecting acute appendicitis in pregnancy in a multi-institution study involving general body MR readers with no specific expertise in MR imaging of the pregnant patient. Retrospective review of MRI examinations on PACS in 42 pregnant patients was evaluated for acute right lower quadrant pain. Three fellowship-trained general body radiologists analyzed the MRI examinations in consensus and attempted to localize the appendix, assess for features of appendicitis, and exclude alternative etiologies for the right lower quadrant pain. Of the 42 MRI examinations, the readers noted 6 cases of acute appendicitis, 16 cases of a normal appendix, and 20 cases involving non-visualization of the appendix but where there were no secondary features of acute appendicitis. Based on the surgical data and clinical follow-up, there were 3 true-positive cases, 3 false-positive cases, 34 true-negative cases, and 2 false-negative cases of acute appendicitis on MRI. This yielded an accuracy of 88.1%, sensitivity of 60%, specificity of 91.9%, positive predictive value of 50%, and negative predictive value of 94.4% for the detection of acute appendicitis in the pregnant patient on MRI. Alternative etiologies for the right lower quadrant pain on MRI included torsion of an ovarian dermoid in 1 case and pyelonephritis in 1 case. MRI is an excellent modality for excluding acute appendicitis in pregnant patients presenting with right lower quadrant pain.

Lack of Utility of the Lysis-Centrifugation Blood Culture Method for Detection of Fungemia in Immunocompromised Cancer Patients

PubMed Central

Creger, Richard J.; Weeman, Kisa E.; Jacobs, Michael R.; Morrissey, Anne; Parker, Pamela; Fox, Robert M.; Lazarus, Hillard M.

1998-01-01

We retrospectively compared the utility of a fungal isolation device (Isolator) versus conventional techniques for recovering fungal organisms from blood cultures obtained from neutropenic cancer patients. Positive cultures were deemed true pathogens, possible pathogens, or contaminants according to laboratory and clinical criteria. Fifty-three patients had 66 positive blood cultures for fungi, nine on multiple occasions. In 20 episodes true pathogens were recovered, 6 from broth medium alone, 4 from the Isolator system alone, and 10 from both systems. False-negative cultures were noted in 4 of 20 (20%) cases in which broth medium was used and in 6 of 20 (30%) cases in which the Isolator system was used. Possible pathogens were detected in 4 of 66 blood culture-positive cases. Forty-two positive cultures were considered contaminants, 1 collected from standard medium and 41 of 42 (98%) which grew only in Isolators. Eleven of 18 patients with true fungal infections expired as a result of infection, while 4 of 33 patients with a contaminant expired, none from a fungal cause. We do not advocate the routine use of Isolator tubes in the evaluation of the febrile, neutropenic patient due to the high rates of false positives and of contamination. PMID:9431970

Incidence of tuberculous meningitis in France, 2000: a capture-recapture analysis.

PubMed

Cailhol, J; Che, D; Jarlier, V; Decludt, B; Robert, J

2005-07-01

To estimate the incidence of culture-positive and culture-negative tuberculous meningitis (TBM) in France in 2000. Capture-recapture method using two unrelated sources of data: the tuberculosis (TB) mandatory notification system (MNTB), recording patients treated by anti-tuberculosis drugs, and a survey by the National Reference Centre (NRC) for mycobacterial drug resistance, recording culture-positive TBM. Of 112 cases of TBM reported to the MNTB, 28 culture-positive and 34 culture-negative meningitis cases were validated (17 duplicates, 3 cases from outside France, 21 false notifications, and 9 lost records were excluded). The NRC recorded 31 culture-positive cases, including 21 known by the MNTB. When the capture-recapture method was applied to the reported culture-positive meningitis cases, the estimated number of meningitis cases was 41 and the incidence was 0.7 cases per million. Sensitivity was 75.6% for the NRC, 68.3% for the MNTB, and 92.7% for both systems together. When sensitivity of the MNTB for culture-positive cases was applied to culture-negative meningitis, the total estimated number of culture-negative meningitis cases was 50 and the incidence was 0.85 cases per million. TBM is underestimated in France. Capture-recapture analysis using different sources to better estimate its incidence is of great interest.

Four Years' Experience in the Diagnosis of Very Long-Chain Acyl-CoA Dehydrogenase Deficiency in Infants Detected in Three Spanish Newborn Screening Centers.

PubMed

Merinero, B; Alcaide, P; Martín-Hernández, E; Morais, A; García-Silva, M T; Quijada-Fraile, P; Pedrón-Giner, C; Dulin, E; Yahyaoui, R; Egea, J M; Belanger-Quintana, A; Blasco-Alonso, J; Fernandez Ruano, M L; Besga, B; Ferrer-López, I; Leal, F; Ugarte, M; Ruiz-Sala, P; Pérez, B; Pérez-Cerdá, C

2018-01-01

Identification of very long-chain acyl-CoA dehydrogenase deficiency is possible in the expanded newborn screening (NBS) due to the increase in tetradecenoylcarnitine (C14:1) and in the C14:1/C2, C14:1/C16, C14:1/C12:1 ratios detected in dried blood spots. Nevertheless, different confirmatory tests must be performed to confirm the final diagnosis. We have revised the NBS results and the results of the confirmatory tests (plasma acylcarnitine profiles, molecular findings, and lymphocytes VLCAD activity) for 36 cases detected in three Spanish NBS centers during 4 years, correlating these with the clinical outcome and treatment. Our aim was to distinguish unambiguously true cases from disease carriers in order to obtain useful diagnostic information for clinicians that can be applied in the follow-up of neonates identified by NBS.Increases in C14:1 and of the different ratios, the presence of two pathogenic mutations, and deficient enzyme activity in lymphocytes (<12% of the intra-assay control) identified 12 true-positive cases. These cases were given nutritional therapy and all of them are asymptomatic, except one. Seventeen individuals were considered disease carriers based on the mild increase in plasma C14:1, in conjunction with the presence of only one mutation and/or intermediate residual activity (18-57%). In addition, seven cases were classified as false positives, with normal biochemical parameters and no mutations in the exonic region of ACADVL. All these carriers and the false positive cases remained asymptomatic. The combined evaluation of the acylcarnitine profiles, genetic results, and residual enzyme activities have proven useful to definitively classify individuals with suspected VLCAD deficiency into true-positive cases and carriers, and to decide which cases need treatment.

Unusual association of amyotrophic lateral sclerosis and myasthenia gravis: A dysregulation of the adaptive immune system?

PubMed

Del Mar Amador, Maria; Vandenberghe, Nadia; Berhoune, Nawel; Camdessanché, Jean-Philippe; Gronier, Sophie; Delmont, Emilien; Desnuelle, Claude; Cintas, Pascal; Pittion, Sophie; Louis, Sarah; Demeret, Sophie; Lenglet, Timothée; Meininger, Vincent; Salachas, François; Pradat, Pierre-François; Bruneteau, Gaëlle

2016-06-01

Myasthenia gravis is an autoimmune disorder affecting neuromuscular junctions that has been associated with a small increased risk of amyotrophic lateral sclerosis (ALS). Here, we describe a retrospective series of seven cases with a concomitant diagnosis of ALS and myasthenia gravis, collected among the 18 French reference centers for ALS in a twelve year period. After careful review, only six patients strictly met the diagnostic criteria for both ALS and myasthenia gravis. In these patients, limb onset of ALS was reported in five (83%) cases. Localization of myasthenia gravis initial symptoms was ocular in three (50%) cases, generalized in two (33%) and bulbar in one (17%). Median delay between onset of the two conditions was 19 months (6-319 months). Anti-acetylcholine receptor antibodies testing was positive in all cases. All patients were treated with riluzole and one had an associated immune-mediated disease. In the one last ALS case, the final diagnosis was false-positivity for anti-acetylcholine receptor antibodies. The co-occurrence of ALS and myasthenia gravis is rare and requires strict diagnostic criteria. Its demonstration needs thoughtful interpretation of electrophysiological results and exclusion of false positivity for myasthenia gravis antibody testing in some ALS cases. This association may be triggered by a dysfunction of adaptive immunity. Copyright © 2016 Elsevier B.V. All rights reserved.

Performance of Momguard, a new non-invasive prenatal testing protocol developed in Korea.

PubMed

Lee, Mi-Young; Cho, Dae-Yeon; Won, Hye-Sung; Hwang, Ah Reum; Jeong, Bada; Kim, Jihun; Oh, Mijin

2015-09-01

To evaluate the performance of Momguard, non-invasive prenatal test (NIPT) for detecting trisomy (T) 21, T18, T13, and sex-chromosome abnormalities recently developed in Korea. This preliminary study formed part of a large prospective cohort study conducted at Asan Medical Center, Seoul, Korea. Only pregnant women who underwent both NIPT and confirmatory karyotyping were included in this study. NIPT results were compared with those of karyotype analyses. Among 93 eligible cases, NIPT results could not be obtained in one case due to a low fetal cell-free DNA fraction. Based on NIPT, eight cases of fetal aneuploidies, including T21 (n=5), T18 (n=2), and T13 (n=1), were identified. For T21 and T18, the sensitivity and specificity of NIPT were both 100%, with a false-positive and false-negative rate of 0% and a positive-predictive value of 100%. One patient classified as having intermediate risk for T13 by NIPT was confirmed to have T13 by karyotyping, and there were no false-negative cases. No cases of sex-chromosome anomalies were detected by NIPT or karyotyping during the study period. Momguard is a reliable screening tool for detecting T21 and T18. For T13 and sex-chromosome anomalies, further prospective studies are necessary to confirm its utility.

Pre-operative prediction of cervical nodal metastasis in papillary thyroid cancer by 99mTc-MIBI SPECT/CT; a pilot study.

PubMed

Tangjaturonrasme, Napadon; Vasavid, Pataramon; Sombuntham, Premsuda; Keelawat, Somboon

2013-06-01

Papillary thyroid cancer has a high prevalence of cervical nodal metastasis. There is no "gold standard" imaging for pre-operative diagnosis. The aim of the present study was to assess the accuracy of pre-operative 99mTc-MBI SPECT/CT in diagnosis of cervical nodal metastasis in patients with papillary thyroid cancer Fifteen patients were performed 99Tc-MlBI SPECT/CT pre-operatively. Either positive pathological report of neck dissection or positive post-treatment I-131 whole body scan with SPECT/CT of neck was concluded for definite neck metastasis. The PPV, NPV, and accuracy of 99mTc-MIBI SPECT/CT were analyzed. The PPV NPV and accuracy were 80%, 88.89%, and 85.71%, respectively. 99mTc-MIBI SPECT/CT could localize the abnormal lymph nodes groups correctly in most cases when compared with pathological results. However the authors found one false positive case with caseating granulomatous lymphadenitis and one false negative case with positive post-treatment 1-131 whole body scan with SPECT/CT of neck on cervical nodes zone II and IV CONCLUSION: 99mTc-MIBI SPECT/CTseem promising for pre-operative staging of cervical nodal involvement in patients with papillary thyroid cancer without the need of using iodinated contrast that may complicate subsequence 1-131 treatment. However, false positive result in granulomatous inflammatory nodes should be aware of especially in endemic areas. 99mTc-MIBI SPECT/CT scan shows a good result when compared with previous study of CT or MRI imaging. The comparative study between different imaging modality and the extension of neck dissection according to MIBI result seems interesting.

Clinical experience of laboratory follow-up with noninvasive prenatal testing using cell-free DNA and positive microdeletion results in 349 cases.

PubMed

Schwartz, S; Kohan, M; Pasion, R; Papenhausen, P R; Platt, L D

2018-02-01

Screening via noninvasive prenatal testing (NIPT) involving the analysis of cell-free DNA (cfDNA) from plasma has become readily available to screen for chromosomal and DNA aberrations through maternal blood. This report reviews a laboratory's experience with follow-up of positive NIPT screens for microdeletions. Patients that were screened positive by NIPT for a microdeletion involving 1p, 4p, 5p, 15q, or 22q who underwent diagnostic studies by either chorionic villus sampling or amniocentesis were evaluated. The overall positive predictive value for 349 patients was 9.2%. When a microdeletion was confirmed, 39.3% of the cases had additional abnormal microarray findings. Unrelated abnormal microarray findings were detected in 11.8% of the patients in whom the screen positive microdeletion was not confirmed. Stretches of homozygosity in the microdeletion were frequently associated with a false positive cfDNA microdeletion result. Overall, this report reveals that while cfDNA analysis will screen for microdeletions, the positive predictive value is low; in our series it is 9.2%. Therefore, the patient should be counseled accordingly. Confirmatory diagnostic microarray studies are imperative because of the high percentage of false positives and the frequent additional abnormalities not delineated by cfDNA analysis. © 2018 John Wiley & Sons, Ltd.

The effect of sample storage on the performance and reproducibility of the galactomannan EIA test.

PubMed

Kimpton, George; White, P Lewis; Barnes, Rosemary A

2014-08-01

Galactomannan enzyme immune assay (GM EIA) is a nonculture test for detecting invasive aspergillosis (IA) forming a key part of diagnosis and management. Recent reports have questioned the reproducibility of indices after sample storage. To investigate this, 198 serum samples (72 from cases and 126 from controls) and 61 plasma samples (24 from cases and 37 from controls), initially tested between 2010 and 2013, were retested to determine any change in index. Data were also collected on circulatory protein levels for false-positive serum samples. Serum indices significantly declined on retesting (median: initial, 0.50, retest, 0.23; P < 0.0001). This was shown to be diagnosis dependent as the decline was apparent on retesting of control samples (median: initial 0.50, retest 0.12; P < 0.0001), but was not evident with case samples (median: initial, 0.80, retest, 0.80; P = 0.724). Plasma samples showed little change on reanalysis after long-term storage at 4°C. Retesting after freezing showed a decrease in index values for controls (median: initial 0.40, retest 0.26; P = 0.0505), but no significant change in cases. Circulatory proteins showed a correlation between serum albumin concentration and difference in index value on retesting. Overall, this study suggests that a lack of reproducibility in GM EIA positivity is only significant when disease is absent. Retesting after freezing helps to differentiate false-positive GM EIA results and, with consecutive positivity, could help to improve accuracy in predicting disease status. The freezing of samples prior to testing could potentially reduce false-positivity rates and the need to retest. © The Author 2014. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Intrathoracic stomach mimicking bone metastasis from thyroid cancer in whole-body iodine-131 scan diagnosed by SPECT/CT.

PubMed

García-Gómez, Francisco Javier; la Riva-Pérez, Pablo Antonio de; Calvo-Morón, Cinta; Buján-Lloret, Cristina; Cambil-Molina, Teresa; Castro-Montaño, Juan

2017-01-01

The whole-body iodine-131 scintigraphy is an imaging technique in monitoring patients with a history of thyroid cancer. Although the rate of false positives is negligible, it is not nonexistent. We report the case of an intervened and treated patient for thyroid cancer with good clinical and biochemical response. Scintigraphic findings were consistent with unsuspected bone metastasis. Fused SPECT/CT data allowed accurate diagnosis of giant diaphragmatic hernia associated with intrathoracic stomach, a very rare pathology that can lead to false positive results.

The Added Value of a Single-photon Emission Computed Tomography-Computed Tomography in Sentinel Lymph Node Mapping in Patients with Breast Cancer and Malignant Melanoma.

PubMed

Bennie, George; Vorster, Mariza; Buscombe, John; Sathekge, Mike

2015-01-01

Single-photon emission computed tomography-computed tomography (SPECT-CT) allows for physiological and anatomical co-registration in sentinel lymph node (SLN) mapping and offers additional benefits over conventional planar imaging. However, the clinical relevance when considering added costs and radiation burden of these reported benefits remains somewhat uncertain. This study aimed to evaluate the possible added value of SPECT-CT and intra-operative gamma-probe use over planar imaging alone in the South African setting. 80 patients with breast cancer or malignant melanoma underwent both planar and SPECT-CT imaging for SLN mapping. We assessed and compared the number of nodes detected on each study, false positive and negative findings, changes in surgical approach and or patient management. In all cases where a sentinel node was identified, SPECT-CT was more accurate anatomically. There was a significant change in surgical approach in 30 cases - breast cancer (n = 13; P 0.001) and malignant melanoma (n = 17; P 0.0002). In 4 cases a node not identified on planar imaging was seen on SPECT-CT. In 16 cases additional echelon nodes were identified. False positives were excluded by SPECT-CT in 12 cases. The addition of SPECT-CT and use of intra-operative gamma-probe to planar imaging offers important benefits in patients who present with breast cancer and melanoma. These benefits include increased nodal detection, elimination of false positives and negatives and improved anatomical localization that ultimately aids and expedites surgical management. This has been demonstrated in the context of industrialized country previously and has now also been confirmed in the setting of a emerging-market nation.

[Evaluation of serum PIVKA-II by Lumipulse PrestoII assay].

PubMed

Hiramatsu, Kumiko; Tanaka, Yasuhito; Takagi, Kazumi; Kani, Satomi; Goto, Takaaki; Takasaka, Yoshimitsu; Matsuura, Kentaro; Sugauchi, Fuminaka; Moriyama, Kazushige; Murakami, Hiroshi; Kitajima, Sachiko; Mizokami, Masashi

2009-03-01

Measurements of serum concentrations of Des-gamma-carboxy Prothrombin (PIVKA-II) are widely used for diagnosing hepatocellular carcinoma (HCC). Recently, in Lumipulsef assay, it was reported that antibodies against alkaline phosphatase (ALP) derived from anti bleeding sheets led false high values of PIVKA-II in the patients with HCC resection. To improve the previous issue, newly developed Lumipulse PrestoII assay was examined. (1) The assay was reliable and positively correlated with the previous assays (Lumipulse f and Picolumi, R = 0.997 and 0.994 (n=115), respectively). (2) Eleven cases, which had false high values of PIVKA-II by the Lumipulsef assay, were examined by the PrestoII assay with excess of inactive ALP. The false high values of 10 cases were improved, but only one was still high. False reactivity of this case was stronger than other cases, more effective adsorption was required. (3) Comparing the absorbent activity of inactive ALP among 6 different kinds, we found inactive ALP with much higher adsorbent activity. When this inactive ALP was applied to assay, false high values of PIVKA-II were improved in all 11 cases. In conclusion, the PrestoII assay, which applies the inactive ALP with high activity, is reliable and useful for clinical screening.

Multimodal intraoperative neuromonitoring in corrective surgery for adolescent idiopathic scoliosis: Evaluation of 354 consecutive cases

PubMed Central

Kundnani, Vishal K; Zhu, Lisa; Tak, HH; Wong, HK

2010-01-01

Background: Multimodal intraoperative neuromonitoring is recommended during corrective spinal surgery, and has been widely used in surgery for spinal deformity with successful outcomes. Despite successful outcomes of corrective surgery due to increased safety of the patients with the usage of spinal cord monitoring in many large spine centers, this modality has not yet achieved widespread popularity. We report the analysis of prospectively collected intraoperative neurophysiological monitoring data of 354 consecutive patients undergoing corrective surgery for adolescent idiopathic scoliosis (AIS) to establish the efficacy of multimodal neuromonitoring and to evaluate comparative sensitivity and specificity. Materials and Methods: The study group consisted of 354 (female = 309; male = 45) patients undergoing spinal deformity corrective surgery between 2004 and 2008. Patients were monitored using electrophysiological methods including somatosensory-evoked potentials and motor-evoked potentials simultaneously. Results: Mean age of patients was 13.6 years (±2.3 years). The operative procedures involved were instrumented fusion of the thoracic/lumbar/both curves, Baseline somatosensory-evoked potentials (SSEP) and neurogenic motor-evoked potentials (NMEP) were recorded successfully in all cases. Thirteen cases expressed significant alert to prompt reversal of intervention. All these 13 cases with significant alert had detectable NMEP alerts, whereas significant SSEP alert was detected in 8 cases. Two patients awoke with new neurological deficit (0.56%) and had significant intraoperative SSEP + NMEP alerts. There were no false positives with SSEP (high specificity) but 5 patients with false negatives with SSEP (38%) reduced its sensitivity. There was no false negative with NMEP but 2 of 13 cases were false positive with NMEP (15%). The specificity of SSEP (100%) is higher than NMEP (96%); however, the sensitivity of NMEP (100%) is far better than SSEP (51%). Due to these results, the overall sensitivity, specificity and positive predictive value of combined multimodality neuromonitoring in this adult deformity series was 100, 98.5 and 85%, respectively. Conclusion: Neurogenic motor-evoked potential (NMEP) monitoring appears to be superior to conventional SSEP monitoring for identifying evolving spinal cord injury. Used in conjunction, the sensitivity and specificity of combined neuromonitoring may reach up to 100%. Multimodality monitoring with SSEP + NMEP should be the standard of care. PMID:20165679

Comparison of Six Automated Treponema-Specific Antibody Assays.

PubMed

Park, Borae G; Yoon, Jihoon G; Rim, John Hoon; Lee, Anna; Kim, Hyon-Suk

2016-01-01

Six different Treponema (TP)-specific immunoassays were compared to the fluorescent treponemal antibody absorption (FTA-ABS) test. A total of 615 samples were tested. The overall percent agreement, analytical sensitivity, and analytical specificity of each assay compared to the FTA-ABS test were as follows: Architect Syphilis TP, 99.2%, 96.8%, and 100%; Cobas Syphilis, 99.8%, 99.4%, and 100%; ADVIA Centaur Syphilis, 99.8%, 99.4%, and 100%; HISCL Anti-TP assay kit, 99.7%, 98.7%, and 100%; Immunoticles Auto3 TP, 99.0%, 97.5%, and 99.6%; Mediace TPLA, 98.0%, 98.1%, and 98.0%. All results that were discrepant between the TP-specific assays were associated with samples from noninfectious cases (11 immunoassay false positives and 7 from previous syphilis cases). Our study demonstrated that TP-specific immunoassays generally showed high sensitivities, specificities, and percentages of agreement compared to FTA-ABS, with rare cases of false-positive or false-negative results. Therefore, most TP-specific immunoassays are acceptable for use in screening for syphilis. However, it is important to perform a thorough review of a patient's clinical and treatment history for interpreting the results of syphilis serology. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

An intrapatient comparison of 99mTc-EDDA/HYNIC-TOC with 111In-DTPA-octreotide for diagnosis of somatostatin receptor-expressing tumors.

PubMed

Gabriel, Michael; Decristoforo, Clemens; Donnemiller, Eveline; Ulmer, Hanno; Watfah Rychlinski, Christine; Mather, Stephen J; Moncayo, Roy

2003-05-01

The aim of this study was to compare the imaging abilities of the recently developed somatostatin analog, (99m)Tc-hydrazinonicotinyl-Tyr(3)-octreotide ((99m)Tc-HYNIC-TOC [(99m)Tc-TOC]), with (111)In-diethylenediaminepentaacetic acid-D-Phe(1)-octreotide ((111)In-OCT [Octreoscan]) in patients undergoing routine somatostatin receptor (SSTR) scintigraphy. Forty-one patients (20 men, 21 women; age range, 29-75 y; mean age, 56.7 y) with either histologically proven or biologically and clinically suspected endocrine tumors were enrolled in the study. Four groups were distinguished: (a) patients being evaluated for the detection and localization of neuroendocrine tumors (n = 6), (b) tumor staging (n = 19), (c) patients being investigated to determine the SSTR status of tumor lesions (n = 11), and (d) patient follow-up studies (n = 5). Each patient received a mean activity of 150 MBq (111)In-OCT and 350-400 MBq (99m)Tc-TOC. Scintigraphy with (99m)Tc-TOC was performed 4 h after injection and scintigraphy with (111)In-OCT was performed 4 and 24 h after injection. SPECT studies of areas of interest were performed 4 h after injection for both tracers as well as at 24 h after injection for (111)In-OCT. The time interval between the studies using each tracer ranged from 2 to 22 d (mean interval, 9.3 d). (111)In-OCT and (99m)Tc-TOC showed an equivalent scan result in 32 patients (78%), 9 cases showed discrepancies (22%), false-negative results with (111)In-OCT were seen in 6 cases (14.6%), whereas (99m)Tc-TOC was false-positive in 2 cases (4.9%). (111)In-OCT was true-negative in both cases. The false-positive findings of the (99m)Tc-TOC studies were caused by nonspecific uptake in the bowel. In 1 case, (99m)Tc-TOC correctly identified a metastasis in the lumbar spine but both scan results were false-positive because of an inflammatory process. In 21 patients with SSTR-expressing tumors, the semiquantitative region-of-interest analysis showed that (99m)Tc-TOC achieved higher tumor-to-normal tissue ratios than (111)In-OCT. This study revealed a higher sensitivity of (99m)Tc-TOC as compared with (111)In-OCT as an imaging agent for the localization of SSTR-expressing tumors. To avoid false-positive findings with (99m)Tc-OCT due to nonspecific tracer accumulation, additional scanning at 1-2 h after injection should be done.

Diagnostic sensitivity and specificity of in situ hybridization and immunohistochemistry for Eastern equine encephalitis virus and West Nile virus in formalin-fixed, paraffin-embedded brain tissue of horses.

PubMed

Pennick, Kate E; McKnight, Christy A; Patterson, Jon S; Latimer, Kenneth S; Maes, Roger K; Wise, Annabel G; Kiupel, Matti

2012-03-01

Immunohistochemistry (IHC) and in situ hybridization (ISH) can be used either to detect or to differentiate between Eastern equine encephalitis virus (EEEV) and West Nile virus (WNV) within formalin-fixed, paraffin-embedded (FFPE) brain tissue of horses. To compare the diagnostic sensitivity and specificity of ISH and IHC, FFPE brain tissue from 20 EEEV-positive horses and 16 WNV-positive horses were tested with both EEEV and WNV oligoprobes and EEEV- and WNV-specific antibodies. Reverse transcription polymerase chain reaction (RT-PCR) for detection of EEEV and WNV was used as the gold standard to confirm infection. All horses that tested positive for EEEV by RT-PCR also tested positive by IHC and ISH, except for 1 case that was false-negative by ISH. In contrast, all horses that tested positive for WNV by RT-PCR tested negative by IHC and only 2 horses tested positive by ISH. No false-positives were detected with either method for both viruses. Both IHC and ISH are highly specific and sensitive diagnostic methods to detect EEEV in equine FFPE brain tissues, although neither appear effective for the diagnosis of WNV in equine neurologic cases.

Diagnosing periprosthetic infection: false-positive intraoperative Gram stains.

PubMed

Oethinger, Margret; Warner, Debra K; Schindler, Susan A; Kobayashi, Hideo; Bauer, Thomas W

2011-04-01

Intraoperative Gram stains have a reported low sensitivity but high specificity when used to help diagnose periprosthetic infections. In early 2008, we recognized an unexpectedly high frequency of apparent false-positive Gram stains from revision arthroplasties. The purpose of this report is to describe the cause of these false-positive test results. We calculated the sensitivity and specificity of all intraoperative Gram stains submitted from revision arthroplasty cases during a 3-month interval using microbiologic cultures of the same samples as the gold standard. Methods of specimen harvesting, handling, transport, distribution, specimen processing including tissue grinding/macerating, Gram staining, and interpretation were studied. After a test modification, results of specimens were prospectively collected for a second 3-month interval, and the sensitivity and specificity of intraoperative Gram stains were calculated. The retrospective review of 269 Gram stains submitted from revision arthroplasties indicated historic sensitivity and specificity values of 23% and 92%, respectively. Systematic analysis of all steps of the procedure identified Gram-stained but nonviable bacteria in commercial broth reagents used as diluents for maceration of periprosthetic membranes before Gram staining and culture. Polymerase chain reaction and sequencing showed mixed bacterial DNA. Evaluation of 390 specimens after initiating standardized Millipore filtering of diluent fluid revealed a reduced number of positive Gram stains, yielding 9% sensitivity and 99% specificity. Clusters of false-positive Gram stains have been reported in other clinical conditions. They are apparently rare related to diagnosing periprosthetic infections but have severe consequences if used to guide treatment. Even occasional false-positive Gram stains should prompt review of laboratory methods. Our observations implicate dead bacteria in microbiologic reagents as potential sources of false-positive Gram stains.

Evaluation of fluorescent-antibody tests as a means of confirming infant botulism.

PubMed Central

Glasby, C; Hatheway, C L

1984-01-01

Fluorescent-antibody techniques were evaluated for confirming infant botulism. Seventy-seven stool specimens from suspected cases were examined. All 34 specimens containing viable Clostridium botulinum at time of study gave positive results (29 on direct smears and 34 on enrichments). Two false-positive reactions were observed. Images PMID:6394626

False-negative BRAF V600E mutation results on fine-needle aspiration cytology of papillary thyroid carcinoma.

PubMed

Paek, Se Hyun; Kim, Byung Seup; Kang, Kyung Ho; Kim, Hee Sung

2017-11-13

The BRAF V600E mutation is highly specific for papillary thyroid carcinoma (PTC). A test for this mutation can increase the diagnostic accuracy of fine-needle aspiration cytology (FNAC), but a considerably high false-negative rate for the BRAF V600E mutation on FNAC has been reported. In this study, we investigated the risk factors associated with false-negative BRAF V600E mutation results on FNAC. BRAF V600E mutation results of 221 PTC nodules between December 2011 and June 2013 were retrospectively reviewed. BRAF V600E mutation results on both preoperative FNAC and postoperative formalin-fixed, paraffin-embedded (FFPE) samples were compared. We investigated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of BRAF V600E mutation results on FNAC. And, we identified the risk factors associated with false-negative results. Of 221 PTC nodules, 150 (67.9%) on FNAC and 185 (83.7%) on FFPE samples were BRAF V600E mutation positive. The sensitivity, specificity, PPV, and NPV for BRAF V600E mutation testing with FNAC were 80.5, 97.2, 99.3, and 49.3%, respectively. Thirty-six (16.3%) BRAF V600E mutation-negative nodules on FNAC were mutation positive on FFPE sample analysis. Risk factors for these false-negative results were age, indeterminate FNAC results (nondiagnostic, atypia of undetermined significance (AUS), and findings suspicious for PTC), and PTC subtype. False-negative rate of BRAF mutation testing with FNAC for thyroid nodules is increased in cases of old age, indeterminate FNAC pathology results, and certain PTC subtypes. Therapeutic surgery can be considered for these cases. A well-designed prospective study with informed consent of patients will be essential for more informative results.

Computer-aided marginal artery detection on computed tomographic colonography

NASA Astrophysics Data System (ADS)

Wei, Zhuoshi; Yao, Jianhua; Wang, Shijun; Liu, Jiamin; Summers, Ronald M.

2012-03-01

Computed tomographic colonography (CTC) is a minimally invasive technique for colonic polyps and cancer screening. The marginal artery of the colon, also known as the marginal artery of Drummond, is the blood vessel that connects the inferior mesenteric artery with the superior mesenteric artery. The marginal artery runs parallel to the colon for its entire length, providing the blood supply to the colon. Detecting the marginal artery may benefit computer-aided detection (CAD) of colonic polyp. It can be used to identify teniae coli based on their anatomic spatial relationship. It can also serve as an alternative marker for colon localization, in case of colon collapse and inability to directly compute the endoluminal centerline. This paper proposes an automatic method for marginal artery detection on CTC. To the best of our knowledge, this is the first work presented for this purpose. Our method includes two stages. The first stage extracts the blood vessels in the abdominal region. The eigenvalue of Hessian matrix is used to detect line-like structures in the images. The second stage is to reduce the false positives in the first step. We used two different masks to exclude the false positive vessel regions. One is a dilated colon mask which is obtained by colon segmentation. The other is an eroded visceral fat mask which is obtained by fat segmentation in the abdominal region. We tested our method on a CTC dataset with 6 cases. Using ratio-of-overlap with manual labeling of the marginal artery as the standard-of-reference, our method yielded true positive, false positive and false negative fractions of 89%, 33%, 11%, respectively.

Paracheck Pf compared with microscopy for diagnosis of Plasmodium falciparum malaria among children in Tanga City, north-eastern Tanzania.

PubMed

Kamugisha, M L; Msangeni, H; Beale, E; Malecela, E K; Akida, J; Ishengoma, D R S; Lemnge, M M

2008-01-01

Malaria is a major public health problem particularly in rural Sub-Saharan Africa. In most urban areas, malaria transmission intensity is low thus monitoring trends using reliable tools is crucial to provide vital information for future management of the disease. Rapid diagnostic tests (RDT) such as Paracheck Pf are now increasingly adopted for Plasmodium falciparum malaria diagnosis and are advantageous and cost effective alternative to microscopy. This cross sectional survey was carried out during June 2005 to determine the prevalence of malaria in an urban setting and compare microscopy diagnosis versus Paracheck Pf for detecting Plasmodium falciparum. Blood samples from a total of 301 children (< 10 years) attending outpatient clinic at Makorora Health Centre, in Tanga, Tanzania were examined for the presence of malaria. Twenty-nine (9.6%) of the children were positive to malaria by microscopy while 30 (10.0%) were positive by Paracheck test. Three out of 30 positive cases detected by Paracheck were negative by microscopy; thus considered to be false positive results. For the 271 Paracheck Pf negative cases, 2 were positive by microscopy; yielding 2 false negative results. Paracheck Pf sensitivity and specificity were 93.1% and 98.9%, respectively. P. falciparum was the only malarial species observed among the 29 microscopy positive cases. The prevalence of anaemia among the children was 53.16%. These findings indicate a low prevalence of malaria in Tanga City and that Paracheck Pf can be an effective tool for malaria diagnosis.

Screening for Binge Eating Disorders Using the Patient Health Questionnaire in a Community Sample

PubMed Central

Striegel-Moore, Ruth H.; Perrin, Nancy; DeBar, Lynn; Wilson, G. Terence; Rosselli, Francine; Kraemer, Helena C.

2009-01-01

Objective To examine the operating characteristics of the Patient Health Questionnaire eating disorder module (PHQ-ED) for identifying bulimia nervosa/binge eating disorder (BN/BED) or recurrent binge eating (RBE) in a community sample, and to compare true positive (TP) versus false positive (FP) cases on clinical validators. Method 259 screen positive individuals and a random sample of 89 screen negative cases completed a diagnostic interview. Sensitivity, specificity, and Positive Predictive Value (PPV) were calculated. TP and FP cases were compared using t-tests and Chi-Square tests. Results The PHQ-ED had high sensitivity (100%) and specificity (92%) for detecting BN/BED or RBE, but PPV was low (15% or 19%). TP and FP cases did not differ significantly on frequency of subjective bulimic episodes, objective overeating, restraint, on BMI, and on self-rated health. Conclusions The PHQ-ED is recommended for use in large populations only in conjunction with follow-up questions to rule out cases without objective bulimic episodes. PMID:19424976

Comparison of results for morphine urinalyses by radioimmunoassay and thin-layer chromatography in a narcotic clinic setting.

PubMed

Kokoski, R J; Jain, M

1975-03-01

Radioimmunoassay (RIA) and thin-layer chromatography (TLC) were compared for morphine detection in an actual narcotic clinic setting. A choice of urines from all those screened by TLC allowed a critical comparison as to actual use or non-use of narcotic drugs, rather than a sampling at random in which the question of possible false positives or negatives cannot be conclusively answered. Although RIA is more sensitive than TLC, its advantage is apparent only in those cases where urine specimens are difficult to obtain frequently regularly or where the use of morphine is suspected by the positive identification of quinine in urine that was morphine-negative by TLC. In a selected group of negative and positive specimens chosen without conscious bias, the two methods gave consistently similar results, indicating that the modified TLC method provided a few or no false positives or negatives if the negatives were from those cases that were not positive anytime up to 3-4 days before urine collection. We conclude that RIA can be of significant value as a supplement to a TLC screening program, without sacrificing the many advantages that TLC has to offer.

Application of strict criteria in adrenal venous sampling increases the proportion of missed patients with unilateral disease who benefit from surgery for primary aldosteronism.

PubMed

Kline, Gregory; Leung, Alexander; So, Benny; Chin, Alex; Harvey, Adrian; Pasieka, Janice L

2018-06-01

Adrenal vein sampling (AVS) is intended to confirm unilateral forms of primary aldosteronism, which are amenable to surgical cure. Excessively strict AVS criteria to define lateralization may result in many patients incorrectly categorized as bilateral primary aldosteronism and opportunity for surgical cure missed. Retrospective review of an AVS-primary aldosteronism database in which surgical cases are verified by standardized outcomes. Having used 'less strict' AVS criteria for lateralization, we examined the distribution of AVS lateralization indices in our confirmed unilateral primary aldosteronism cases both with and without cosyntropin stimulation. The proportion of proven unilateral cases that would have been missed with stricter AVS interpretation criteria was calculated. Particular focus was given to the proportion of missed cases according to use of international guidelines. False-positive lateralization with 'less strict' interpretation was also calculated. Of 80 surgical primary aldosteronism cases, 10-23% would have been missed with AVS lateralization indices of 3 : 1 to 5 : 1, with or without cosyntropin. If strict selectivity indices (for confirmation of catheterization) were combined with strict lateralization indices, up to 70% of unilateral primary aldosteronism cases could have been missed. Use of Endocrine Society AVS guidelines would have missed 21-43% of proven unilateral cases. 'Less strict' AVS interpretation yielded one case (1.2%) of false lateralization. Excessively strict AVS interpretation criteria will result in a high rate of missed unilateral primary aldosteronism with subsequent loss of opportunity for intervention. Use of more lenient lateralization criteria will improve the detection rate of unilateral primary aldosteronism with very low false-positive rate.

Evaluation of usefulness of fine-needle aspiration cytology in the diagnosis of tumours of the accessory parotid gland: a preliminary analysis of a case series in Japan.

PubMed

Iguchi, Hiroyoshi; Wada, Tadashi; Matsushita, Naoki; Oishi, Masahiro; Teranishi, Yuichi; Yamane, Hideo

2014-07-01

The accuracy and sensitivity of fine-needle aspiration cytology (FNAC) in this analysis were not satisfactory, and the false-negative rate seemed to be higher than for parotid tumours. The possibility of low-grade malignancy should be considered in the surgical treatment of accessory parotid gland (APG) tumours, even if the preoperative results of FNAC suggest that the tumour is benign. Little is known about the usefulness of FNAC in the preoperative evaluation of APG tumours, probably due to the paucity of APG tumour cases. We examined the usefulness of FNAC in the detection of malignant APG tumours. We conducted a retrospective analysis of 3 cases from our hospital, along with 18 previously reported Japanese cases. We compared the preoperative FNAC results with postoperative histopathological diagnoses of APG tumours and evaluated the accuracy, sensitivity, specificity and false-negative rates of FNAC in detecting malignant APG tumours. There were four false-negative cases (19.0%), three of mucoepidermoid carcinomas and one of malignant lymphoma. One false-positive result was noted in the case of a myoepithelioma, which was cytologically diagnosed as suspected adenoid cystic carcinoma. The accuracy, sensitivity and specificity of FNAC in detecting malignant tumours were 76.2%, 60.0% and 90.9%, respectively.

Development of a computer-aided detection system for lung cancer diagnosis

NASA Astrophysics Data System (ADS)

Suzuki, Hideo; Inaoka, Noriko; Takabatake, Hirotsugu; Mori, Masaki; Sasaoka, Soichi; Natori, Hiroshi; Suzuki, Akira

1992-06-01

This paper describes a modified system for automatic detection of lung nodules by means of chest x ray image processing techniques. The objective of the system is to help radiologists to improve their accuracy in cancer detection. It is known from retrospective studies of chest x- ray images that radiologists fail to detect about 30 percent of lung cancer cases. A computerized method for detecting lung nodules would be very useful for decreasing the proportion of such oversights. Our proposed system consists of five sub-systems, for image input, lung region determination, nodule detection, rule-based false-positive elimination, and statistical false-positive elimination. In an experiment with the modified system, using 30 lung cancer cases and 78 normal control cases, we obtained figures of 73.3 percent and 89.7 percent for the sensitivity and specificity of the system, respectively. The system has been developed to run on the IBM* PS/55* and IBM RISC System/6000* (RS/6000), and we give the processing time for each platform.

INITIAL IMPRESSIONS OF THE DIAGNOSTIC USE OF RADIOACTIVE PHOSPHORUS IN OPHTHALMOLOGY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stankovic, M.

Out of 10 cases, the use of radioactive P established four cases of malignant growths on the retina that were histologically confirmed, but gave falsely positive results in two cases immediately after surgical intervention, and was negative in the other four cases. It was concluded that the method appears justified in diagnosing intraocular tumors if regarded as an auxiliary method and not as the decisive factor. (P.C.H.)

Ranitidine interference with standard amphetamine immunoassay.

PubMed

Liu, Li; Wheeler, Sarah E; Rymer, Jacqueline A; Lower, Darla; Zona, Jayne; Peck Palmer, Octavia M; Tamama, Kenichi

2015-01-01

We recently encountered several cases of possible false positive results of amphetamine on the Beckman Coulter AMPH assay, but not on the Siemens EMIT II Plus assay. Our clinical chart review suggested that ranitidine interference may be responsible for the false positive results of the AMPH assays. Blank urine specimens spiked with ranitidine concentrations ranging from 5μg/ml to 5mg/ml were analyzed on both the AMPH and EMIT II Plus assays. To examine if the false positive results were due to assay specific reagent/sample ratios, we prepared 3 different sample to reagent ratios and analyzed them for amphetamine reaction rates on both assays. Ranitidine at 160μg/ml caused a positive interference on the AMPH assay. No interference was observed by ranitidine on the EMIT II Plus assay. Specifically, the sample to reagent ratios tested neither eliminated the positive inference on the AMP assay nor introduced an interference on the EMIT II Plus assay. Unlike the EMIT II Plus assay, the AMPH assay has cross-activity with ranitidine, which is independent of sample to reagent ratio. Copyright © 2014 Elsevier B.V. All rights reserved.

The added value of using mutational profiling in addition to cytology in diagnosing aggressive pancreaticobiliary disease: review of clinical cases at a single center

PubMed Central

2014-01-01

Background This study aimed to better understand the supporting role that mutational profiling (MP) of DNA from microdissected cytology slides and supernatant specimens may play in the diagnosis of malignancy in fine-needle aspirates (FNA) and biliary brushing specimens from patients with pancreaticobiliary masses. Methods Cytology results were examined in a total of 30 patients with associated surgical (10) or clinical (20) outcomes. MP of DNA from microdissected cytology slides and from discarded supernatant fluid was analyzed in 26 patients with atypical, negative or indeterminate cytology. Results Cytology correctly diagnosed aggressive disease in 4 patients. Cytological diagnoses for the remaining 26 were as follows: 16 negative (9 false negative), 9 atypical, 1 indeterminate. MP correctly determined aggressive disease in 1 false negative cytology case and confirmed a negative cytology diagnosis in 7 of 7 cases of non-aggressive disease. Of the 9 atypical cytology cases, MP correctly diagnosed 7 as positive and 1 as negative for aggressive disease. One specimen that was indeterminate by cytology was correctly diagnosed as non-aggressive by MP. When first line malignant (positive) cytology results were combined with positive second line MP results, 12/21 cases of aggressive disease were identified, compared to 4/21 cases identified by positive cytology alone. Conclusions When first line cytology results were uncertain (atypical), questionable (negative), or not possible (non-diagnostic/indeterminate), MP provided additional information regarding the presence of aggressive disease. When used in conjunction with first line cytology, MP increased detection of aggressive disease without compromising specificity in patients that were difficult to diagnose by cytology alone. PMID:25084836

Utility of percutaneous joint aspiration and synovial biopsy in identifying culture-positive infected hip arthroplasty.

PubMed

Cross, M Connor; Kransdorf, Mark J; Chivers, F Spencer; Lorans, Roxanne; Roberts, Catherine C; Schwartz, Adam J; Beauchamp, Christopher P

2014-02-01

Percutaneous synovial biopsy has recently been reported to have a high diagnostic value in the preoperative identification of periprosthetic infection of the hip. We report our experience with this technique in the evaluation of patients undergoing revision hip arthroplasty, comparing results of preoperative synovial biopsy with joint aspiration in identifying an infected hip arthroplasty by bacteriological analysis. We retrospectively reviewed the results of the 110 most recent revision hip arthroplasties in which preoperative synovial biopsy and joint aspiration were both performed. Revision surgery for these patients occurred during the period from September 2005 to March 2012. Using this study group, results from preoperative cultures were compared with preoperative laboratory studies and the results of intraoperative cultures. Synovial aspiration was done using an 18- or 20-gauge spinal needle. Synovial biopsy was done coaxially following aspiration using a 22-gauge Chiba needle or 21-gauge Sure-Cut needle. Standard microbiological analysis was performed on preoperative synovial fluid aspirate and synovial biopsy. Intraoperative tissue biopsy bacteriological analysis results at surgical revision were accepted as the "gold standard" for the presence or absence of infection. Seventeen of 110 (15 %) of patients had intraoperative culture-positive periprosthetic infection. Of these 17 cases, there were ten cases where either the synovial fluid aspiration and/or the synovial biopsy were true positive (sensitivity of 59 %, specificity of 100 %, positive predictive value of 100 % and accuracy of 94 %). There were seven cases where aspiration and biopsy results were both falsely negative, but no false-positive results. Similar results were found for synovial fluid aspiration alone. The results of synovial biopsy alone resulted in the identification of seven infected joints with no false-positive result (sensitivity of 41 %, specificity of 100 %, positive predictive value of 100 %, and accuracy of 91 %). Standard microbiological analyses performed on percutaneous synovial biopsy specimen during the preoperative evaluation of patients undergoing revision hip arthroplasty did not improve detection of culture-positive periprosthetic infection as compared to synovial fluid aspiration alone.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dana Kelly; Kurt Vedros; Robert Youngblood

This paper examines false indication probabilities in the context of the Mitigating System Performance Index (MSPI), in order to investigate the pros and cons of different approaches to resolving two coupled issues: (1) sensitivity to the prior distribution used in calculating the Bayesian-corrected unreliability contribution to the MSPI, and (2) whether (in a particular plant configuration) to model the fuel oil transfer pump (FOTP) as a separate component, or integrally to its emergency diesel generator (EDG). False indication probabilities were calculated for the following situations: (1) all component reliability parameters at their baseline values, so that the true indication ismore » green, meaning that an indication of white or above would be false positive; (2) one or more components degraded to the extent that the true indication would be (mid) white, and “false” would be green (negative) or yellow (negative) or red (negative). In key respects, this was the approach taken in NUREG-1753. The prior distributions examined were the constrained noninformative (CNI) prior used currently by the MSPI, a mixture of conjugate priors, the Jeffreys noninformative prior, a nonconjugate log(istic)-normal prior, and the minimally informative prior investigated in (Kelly et al., 2010). The mid-white performance state was set at ?CDF = ?10 ? 10-6/yr. For each simulated time history, a check is made of whether the calculated ?CDF is above or below 10-6/yr. If the parameters were at their baseline values, and ?CDF > 10-6/yr, this is counted as a false positive. Conversely, if one or all of the parameters are set to values corresponding to ?CDF > 10-6/yr but that time history’s ?CDF < 10-6/yr, this is counted as a false negative indication. The false indication (positive or negative) probability is then estimated as the number of false positive or negative counts divided by the number of time histories (100,000). Results are presented for a set of base case parameter values, and three sensitivity cases in which the number of FOTP demands was reduced, along with the Birnbaum importance of the FOTP.« less

The ethics of providing hope in psychotherapy.

PubMed

Dembo, Justine Sarah; Clemens, Norman A

2013-07-01

The instillation of hope is a common factor in most psychotherapies. A considerable literature exists on the ethics of providing false or positively biased hope in non-psychiatric medical settings, and ethicists have generally concluded that this practice is unethical. However, the literature on the ethics of encouraging hope in psychotherapy, especially in the case of treatment-resistant mental illness, is sparse. The author explores two clinical cases with the intention of examining the nature of hope, false hope, positive illusions, and denial, as they relate to our definitions of mental health and psychotherapy. The cases highlight the ethics of balancing an acknowledgment of likely treatment futility with a desire to hope. Clinical psychological studies on depressive realism and optimistic bias indicate that some degree of positive bias, referred to by some authors as "the optimal margin of illusion," is in fact necessary to promote what we define as "good mental health;" conversely, stark realism is correlated with mild to moderate depression. An examination of the existential literature, including Ernest Becker's work, The Denial of Death, indicates that without the defense mechanism of denial, human beings tend to experience paralytic despair as a result of being fallible, mortal creatures in a frightening world. The combination of these diverse bodies of literature, along with the surprising outcomes of our case examples, leads to an unexpected conclusion: it may occasionally be ethical to encourage some degree of optimistic bias, and perhaps even positive illusion, when treating patients in psychotherapy.

Causes of false-negative for high-grade urothelial carcinoma in urine cytology.

PubMed

Lee, Paul J; Owens, Christopher L; Lithgow, Marie Y; Jiang, Zhong; Fischer, Andrew H

2016-12-01

The Paris System for classifying urine cytology emphasizes identification of high-grade urothelial carcinoma (HGUC). The causes of false-negative urine cytologies (UC) within this system are not well described. We identified 660 cases between 2005 and 2013 with both UC and subsequent cystoscopic biopsies. UC were classified as either Negative for HGUC or "Abnormal" ("Atypical", "Suspicious", and "Malignant"). Apparent false-negative cases were reviewed in a nonblinded fashion by two cytopathologists and two subspecialized genitourinary pathologists. A total of 199 of the 660 cases (30%) were histologically diagnosed as HGUC. The UC were "Abnormal" in 170/199 cases (sensitivity/specificity of 86%/71%). Twenty four apparent false negative cases were available for retrospective review. Five of 24 (21%) cystoscopic biopsies were found not to be HGUC on review (one false positive and four low-grade urothelial carcinoma (LGUC on review). Of the remaining 19 UC, 7 (29%) cytology samples were found to be truly negative on review, 11 (46%) were found to be Atypical, and 1 (4%) suspicious. Of the 12 UC that were at least "Atypical" with histologic HGUC on review: six misses (half) were attributed to obscuring inflammation/blood, four to poor preservation, eight to paucity of abnormal cells, and 1 case to interpretive error; many cases demonstrated overlapping reasons. About one fifth of apparent false negative diagnoses for HGUC can be because of overdiagnosis of HGUC by surgical pathologists. If poor preservation or obscured samples are called nondiagnostic, the sensitivity/specificity of UC for HGUC can be as high as 94%/71%. Diagn. Cytopathol. 2016;44:994-999. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Determining Occurrence Dynamics when False Positives Occur: Estimating the Range Dynamics of Wolves from Public Survey Data.

PubMed

Miller, David A W; Nichols, James D; Gude, Justin A; Rich, Lindsey N; Podruzny, Kevin M; Hines, James E; Mitchell, Michael S

2013-01-01

Large-scale presence-absence monitoring programs have great promise for many conservation applications. Their value can be limited by potential incorrect inferences owing to observational errors, especially when data are collected by the public. To combat this, previous analytical methods have focused on addressing non-detection from public survey data. Misclassification errors have received less attention but are also likely to be a common component of public surveys, as well as many other data types. We derive estimators for dynamic occupancy parameters (extinction and colonization), focusing on the case where certainty can be assumed for a subset of detections. We demonstrate how to simultaneously account for non-detection (false negatives) and misclassification (false positives) when estimating occurrence parameters for gray wolves in northern Montana from 2007-2010. Our primary data source for the analysis was observations by deer and elk hunters, reported as part of the state's annual hunter survey. This data was supplemented with data from known locations of radio-collared wolves. We found that occupancy was relatively stable during the years of the study and wolves were largely restricted to the highest quality habitats in the study area. Transitions in the occupancy status of sites were rare, as occupied sites almost always remained occupied and unoccupied sites remained unoccupied. Failing to account for false positives led to over estimation of both the area inhabited by wolves and the frequency of turnover. The ability to properly account for both false negatives and false positives is an important step to improve inferences for conservation from large-scale public surveys. The approach we propose will improve our understanding of the status of wolf populations and is relevant to many other data types where false positives are a component of observations.

Extraction of advanced geospatial intelligence (AGI) from commercial synthetic aperture radar imagery

NASA Astrophysics Data System (ADS)

Kanberoglu, Berkay; Frakes, David

2017-04-01

The extraction of objects from advanced geospatial intelligence (AGI) products based on synthetic aperture radar (SAR) imagery is complicated by a number of factors. For example, accurate detection of temporal changes represented in two-color multiview (2CMV) AGI products can be challenging because of speckle noise susceptibility and false positives that result from small orientation differences between objects imaged at different times. These cases of apparent motion can result in 2CMV detection, but they obviously differ greatly in terms of significance. In investigating the state-of-the-art in SAR image processing, we have found that differentiating between these two general cases is a problem that has not been well addressed. We propose a framework of methods to address these problems. For the detection of the temporal changes while reducing the number of false positives, we propose using adaptive object intensity and area thresholding in conjunction with relaxed brightness optical flow algorithms that track the motion of objects across time in small regions of interest. The proposed framework for distinguishing between actual motion and misregistration can lead to more accurate and meaningful change detection and improve object extraction from a SAR AGI product. Results demonstrate the ability of our techniques to reduce false positives up to 60%.

Expanded newborn metabolic screening programme in Hong Kong: a three-year journey.

PubMed

Chong, S C; Law, L K; Hui, J; Lai, C Y; Leung, T Y; Yuen, Y P

2017-10-01

No universal expanded newborn screening service for inborn errors of metabolism is available in Hong Kong despite its long history in developed western countries and rapid development in neighbouring Asian countries. To increase the local awareness and preparedness, the Centre of Inborn Errors of Metabolism of the Chinese University of Hong Kong started a private inborn errors of metabolism screening programme in July 2013. This study aimed to describe the results and implementation of this screening programme. We retrieved the demographics of the screened newborns and the screening results from July 2013 to July 2016. These data were used to calculate quality metrics such as call-back rate and false-positive rate. Clinical details of true-positive and false-negative cases and their outcomes were described. Finally, the call-back logistics for newborns with positive screening results were reviewed. During the study period, 30 448 newborns referred from 13 private and public units were screened. Of the samples, 98.3% were collected within 7 days of life. The overall call-back rate was 0.128% (39/30 448) and the false-positive rate was 0.105% (32/30 448). Six neonates were confirmed to have inborn errors of metabolism, including two cases of medium-chain acyl-coenzyme A dehydrogenase deficiency, one case of carnitine-acylcarnitine translocase deficiency, and three milder conditions. One case of maternal carnitine uptake defect was diagnosed. All patients remained asymptomatic at their last follow-up. The Centre of Inborn Errors of Metabolism has established a comprehensive expanded newborn screening programme for selected inborn errors of metabolism. It sets a standard against which the performance of other private newborn screening tests can be compared. Our experience can also serve as a reference for policymakers when they contemplate establishing a government-funded universal expanded newborn screening programme in the future.

Focused abdominal sonography for trauma (FAST) in blunt paediatric abdominal trauma.

PubMed

Faruque, Ahmad Vaqas; Qazi, Saqib Hamid; Khan, Muhammad Arif Mateen; Akhtar, Wassem; Majeed, Amina

2013-03-01

To evaluate the role of focussed abdominal sonography for trauma in blunt paediatric abdominal trauma patients, and to see if the role of computed tomography scan could be limited to only those cases in which sonography was positive. The retrospective study covered 10 years, from January 1,2000 to December 31,2009, and was conducted at the Department of Radiology and Department of Emergency Medicine, Aga Khan University Hospital, Karachi. It comprised cases of 174 children from birth to 14 years who had presented with blunt abdominal trauma and had focussed abdominal sonography for trauma done at the hospital. The findings were correlated with computed tomography scan of the abdomen and clinical follow-up. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of focussed abdominal sonography for trauma were calculated for blunt abdominal trauma. SPSS 17 was used for statistical analysis. Of the total 174 cases, 31 (17.81%) were later confirmed by abdominal scan. Of these 31 children, sonography had been positive in 29 (93.54%) children. In 21 (67.74%) of the 31 children, sonograpy had been true positive; 8 (25%) (8/31) were false positive; and 2 (6%) (2/31) were false negative. There were 6 (19.3%) children in which sonography was positive and converted to laparotomy. There was no significant difference on account of gender (p>0.356). Focussed abdominal sonography for trauma in the study had sensitivity of 91%, specificity of 95%, positive predictive value of 73%, and negative predictive value of 73% with accuracy of 94%. All patients who had negative sonography were discharged later, and had no complication on clinical follow-up. Focussed abdominal sonography for trauma is a fairly reliable mode to assess blunt abdominal trauma in children. It is a useful tool to pick high-grade solid and hollow viscous injury. The results suggest that the role of computed tomography scan can be limited to those cases in which focussed sonography is positive.

False-positive liver scan in a patient with hepatic amyloidosis: case report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suzuki, K.; Okuda, K.; Yoshida, T.

1976-01-01

A case of secondary hepatic amyloidosis exhibiting a large liver and multiple defects on the $sup 198$Au-radiocolloid scintigraph is presented. Biopsy and angiographic studies indicated that the areas of reduced colloid uptake represented heavy amyloid deposition, and the area of the left lobe with contrasting high activity most probably represented compensatory hypertrophy. (auth)

Size and Ultrasound Features Affecting Results of Ultrasound-Guided Fine-Needle Aspiration of Thyroid Nodules.

PubMed

Dong, YiJie; Mao, MinJing; Zhan, WeiWei; Zhou, JianQiao; Zhou, Wei; Yao, JieJie; Hu, YunYun; Wang, Yan; Ye, TingJun

2018-06-01

Our goal was to assess the diagnostic efficacy of ultrasound (US)-guided fine-needle aspiration (FNA) of thyroid nodules according to size and US features. A retrospective correlation was made with 1745 whole thyroidectomy and hemithyroidectomy specimens with preoperative US-guided FNA results. All cases were divided into 5 groups according to nodule size (≤5, 5.1-10, 10.1-15, 15.1-20, and >20 mm). For target nodules, static images and cine clips of conventional US and color Doppler were obtained. Ultrasound images were reviewed and evaluated by two radiologists with at least 5 years US working experience without knowing the results of pathology, and then agreement was achieved. The Bethesda category I rate was higher in nodules larger than 15 mm (P < .05). The diagnostic accuracy was best in nodules of 5 to 10 mm in diameter. The sensitivity, accuracy, PPV, and LR for negative US-guided FNA results were better in nodules with a size range of 5 to 15 mm. The specificity, negative predictive value (NPV), and LR for positive results and the Youden index rose with increasing nodule size. Seventeen false-positive and 60 false-negative results were found in this study. The false-negative rate rose with increasing nodule size. However, the false-positive rate was highest in the group containing the smallest nodules. Nodules with circumscribed margins and those that were nonsolid and nonhypoechoic and had no microcalcifications correlated with Bethesda I FNA results. Nodules with circumscribed margins and those that were nonsolid, heterogeneous, and nonhypoechoic and had increased vascularity correlated with false-negative FNA results. Borders correlated with Bethesda I false-negative and false-positive FNA results. Tiny nodules (≤5 mm) with obscure borders tended to yield false-positive FNA results. Large nodules (>20 mm) with several US features tended to yield false-negative FNA results. © 2017 by the American Institute of Ultrasound in Medicine.

First-trimester visualization of the fourth ventricle in fetuses with and without spina bifida.

PubMed

Solt, Ido; Acuna, Joann G; Adeniji, Beni A; Mirocha, James; Kim, Matthew J; Rotmensch, Siegfried

2011-12-01

The purpose of this study was to examine the efficacy of nonvisualization of the fourth ventricle for first-trimester detection of spina bifida. A total of 250 digitally stored sonographic examinations at gestational ages of 11 weeks to 13 weeks 6 days (245 normal and 5 randomly interspersed spina bifida cases) were retrospectively analyzed by 4 blinded reviewers for the presence or absence of the fourth ventricle followed by an anteroposterior ventricular dimension measurement. The ventricle size was related to the crown-rump length and gestational age by linear regression analysis and Pearson correlation. The fourth ventricle was identified in 971 of 1000 image readings (97.1%). False-negative and false-positive readings occurred in 11 of 20 (55.0%) and 20 of 980 (2.0%) cases, respectively (sensitivity, 0.45; specificity, 0.98.). False-negative and false-positive readings were evenly distributed throughout the gestational age range. When the ventricular size was measurable, its mean dimensions increased linearly with gestational age and were below the fifth percentile in 10 of 245 (4.0%) normal and 0 of 4 spina bifida cases, respectively. Intraclass correlation coefficient estimates were calculated based on the 2-way analysis of variance model and found to be 0.30 for a single rater and 0.64 for the mean of 4 raters. Nonvisualization of the first-trimester fourth ventricle is a less robust screening parameter for spina bifida than previously published.

Omitting duodenal biopsy in children with suspected celiac disease and extra-intestinal symptoms.

PubMed

Bozzola, Mauro; Meazza, Cristina; Gertosio, Chiara; Pagani, Sara; Larizza, Daniela; Calcaterra, Valeria; Luinetti, Ombretta; Farello, Giovanni; Tinelli, Carmine; Iughetti, Lorenzo

2017-07-15

The aim of our study is to evaluate if in children with highly positive serology and HLA-DQ2/DQ8 (triple test, TT) and only extra-intestinal symptoms, it is possible to omit performing an intestinal biopsy for celiac disease (CD) diagnosis, as suggested by the new European Society for Pediatric Gastroenterology, Hepatology and Nutrition ESPGHAN guidelines. In this retrospective study a total of 105 patients, suspected of having CD because of extra-intestinal symptoms and showing serum tissue transglutaminase antibody (anti-tTG) and anti-endomysial antibody (EMA) measurements and HLA genotyping, were considered for the final analysis (33 boys and 72 girls; age range 1.5-17.6 years). Histological findings confirmed diagnosis of CD in 97 (92.4%) patients. Forty-one patients (39%) showed anti-tTG >10 times normal values, positive EMA and positive HLA-DQ2/DQ8 (positive TT). All of them had a diagnosis of CD, therefore there were no false positive cases. Sixty-four patients were negative for the TT. In eight cases, CD was ruled out and these were considered true negative cases. In the remaining 56 negative TT patients, intestinal biopsy confirmed CD diagnosis and they were considered false negatives. Based on these results, specificity for the TT was 100% and sensitivity was 42.3%. On the basis of the present study, diagnosis of CD can be reliably performed without a duodenal biopsy in children with only extra-intestinal symptoms.

The value of a transformation zone component in anal cytology to detect HSIL.

PubMed

Roberts, Jennifer M; Jin, Fengyi; Thurloe, Julia K; Ekman, Deborah; Adams, Marjorie K; McDonald, Ross L; Biro, Clare; Poynten, I Mary; Grulich, Andrew E; Farnsworth, Annabelle

2016-08-01

In a cytology-based screening program intended to prevent anal cancer, the anal transformation zone (TZ) should be adequately sampled because it is the site most susceptible to the development of the cancer precursor, high-grade squamous intraepithelial lesion (HSIL). An adequate TZ component is defined as comprising at least 10 rectal columnar or squamous metaplastic cells. In the current study, the authors examined whether the presence of a TZ component in anal cytology correlated with the detection of histological HSIL. In a natural history study of anal human papillomavirus infection in homosexual men, all participants underwent liquid-based cytology and high-resolution anoscopy (HRA) with or without biopsy at each visit. True-negative cytology (negative cytology with non-HSIL biopsy or negative HRA), false-negative cytology (negative cytology with HSIL biopsy), and true-positive cytology (abnormal cytology with HSIL biopsy) were compared with regard to the presence or absence of a TZ component. Of 617 participants, baseline results included 155 true-positive results, 191 true-negative results, and 31 false-negative results. The absence of an adequate TZ component was found to be significantly higher for false-negative (32.3%) than for either true-positive (11.0%; P = .0034) or true-negative (13.1%; P = .0089) results. Significantly more false-negative cases lacked a TZ component compared with either true-positive or true-negative cases. TZ cells may be an important indicator of sample quality for anal cytology because, unlike cervical sampling, the anal canal is not visualized during cytology sampling. Cancer Cytopathol 2016;124:596-601. © 2016 American Cancer Society. © 2016 American Cancer Society.

The Diagnostic Validity of the 13C-Urea Breath Test in the Gastrectomized Patients: Single Tertiary Center Retrospective Cohort Study

PubMed Central

Kwon, Yong Hwan; Kim, Nayoung; Lee, Ju Yup; Choi, Yoon Jin; Yoon, Kichul; Yoon, Hyuk; Shin, Cheol Min; Park, Young Soo; Lee, Dong Ho

2014-01-01

Background: This study was conducted to evaluate the diagnostic validity of the 13C-urea breath test (13C-UBT) in the remnant stomach after partial gastrectomy for gastric cancer. Methods: The 13C-UBT results after Helicobacter pylori eradication therapy was compared with the results of endoscopic biopsy-based methods in the patients who have received partial gastrectomy for the gastric cancer. Results: Among the gastrectomized patients who showed the positive 13C-UBT results (≥ 2.5‰, n = 47) and negative 13C-UBT results (< 2.5‰, n = 114) after H. pylori eradication, 26 patients (16.1%) and 4 patients (2.5%) were found to show false positive and false negative results based on biopsy-based methods, respectively. The sensitivity, specificity, false positive rate, and false negative rate for the cut-off value of 2.5‰ were 84.0%, 80.9%, 19.1%, and 16.0%, respectively. The positive and negative predictive values were 44.7% and 96.5%, respectively. In the multivariate analysis, two or more H. pylori eradication therapies (odds ratio = 3.248, 95% confidence interval= 1.088–9.695, P = 0.035) was associated with a false positive result of the 13C-UBT. Conclusions: After partial gastrectomy, a discordant result was shown in the positive 13C-UBT results compared to the endoscopic biopsy methods for confirming the H. pylori status after eradication. Additional endoscopic biopsy-based H. pylori tests would be helpful to avoid unnecessary treatment for H. pylori eradication in these cases. PMID:25574466

IgM rheumatoid factor removal and performance of the FTA-ABS (IgM) test in congenital syphilis.

PubMed

Meyer, M P; Roditi, D; Louw, S

1992-08-01

To determine the performance of the FTA-ABS (IgM) test in congenital syphilis after eliminating interference by IgM rheumatoid factor (RF) and preventing competitive inhibition by IgG. The FTA-ABS (IgM) test was carried out before and after RF removal (achieved by immunoprecipitation of the IgG) in infants with congenital syphilis and controls. Newborns delivered in the Peninsula Maternal and Neonatal Services in Cape Town and infants presenting at Red Cross War Memorial Children's Hospital. Infants with congenital syphilis aged 0-4 months were divided into those with clinical signs at presentation and those who were asymptomatic at delivery. In addition, patients without congenital syphilis but with similar clinical signs at presentation were investigated as were control infants. The diagnosis of congenital syphilis was based on the criteria suggested by Kaufman et al (1977). Amongst symptomatic infants with congenital syphilis the FTA-ABS (IgM) test was positive in 34 (92%) of 37 cases prior to abolishing the RF effect and in 29 (78.4%) of 37 cases afterwards (p = 0.19). In 12 cases of congenital syphilis who were asymptomatic at birth, 10 had positive FTA-ABS (IgM) tests before RF removal and only three had positive tests afterwards (p = 0.006). False positive tests were not found amongst 15 symptomatic infants whose clinical features mimicked those of the infants with congenital syphilis. Among 51 healthy infants the test had a false-positive rate of 2% in newborns and 13% in older infants. The false positive reactions were eradicated by IgG precipitation. Following IgG and RF removal there was an improvement in the specificity of the FTA-ABS (IgM) test but this was at the expense of a loss of sensitivity, particularly in asymptomatic newborns. For newborns, if the FTA-ABS (IgM) test was positive, the patient was likely to require treatment for congenital syphilis, regardless of whether the result was due to the presence of RF or specific IgM.

Cross-Reactivity of Chloroquine and Hydroxychloroquine With DRI Amphetamine Immunoassay.

PubMed

Gomila, Isabel; Quesada, Loreto; López-Corominas, Victoria; Fernández, Julia; Servera, Miguel Á; Sahuquillo, Laura; Dastis, Macarena; Torrents, Albert; Barceló, Bernardino

2017-04-01

Chloroquine and hydroxychloroquine are medical drugs used to treat the chemoprophylaxis of malaria and a second-line anti-inflammatory drug. We performed a study of cross-reactivity of chloroquine and hydroxychloroquine in the DRI Amphetamine Assay inspired by a case report of a self-ingestion of chloroquine after a family dispute, that involved the following: (1) an in vitro study with control samples of healthy subjects, (2) an in vivo study with samples of patients with rheumatoid arthritis, and (3) an evaluation of the cross-reactivity of chloroquine and hydroxychloroquine in 3 additional immunoassays. In the case report, the Amphetamine DRI assay resulted positive both at 1000 ng/mL cutoff (1507 and 1137 ng/mL) and at 500 ng/mL cutoff (1178 and 642 ng/mL). Chloroquine urine levels were 103,900 and 100,900 ng/mL at 5 and 9 hours after ingestion. The results with control samples showed a positive cross-reactivity of chloroquine in the DRI Amphetamine Assay (approximately 0.74% and 0.89% at cutoff of 1000 and 500 ng/mL, respectively). Hydroxychloroquine did not cross-react with the DRI Amphetamine Assay up to 1,000,000 ng/mL. In patients treated with chloroquine or hydroxychloroquine, DRI Amphetamine did not produce false-positive results. The comparative assay study showed a positive cross-reactivity of chloroquine in the Emit II Plus Amphetamines Assay with control samples. Chloroquine can cause false-positive results in the DRI Amphetamine Assay when it is present at high concentrations. Hydroxychloroquine did not produce false-positive results neither in the DRI Amphetamine Assay nor in the others immunoassays evaluated.

Creatine transporter deficiency: prevalence among patients with mental retardation and pitfalls in metabolite screening.

PubMed

Arias, Angela; Corbella, Marc; Fons, Carmen; Sempere, Angela; García-Villoria, Judit; Ormazabal, Aida; Poo, Pilar; Pineda, Mercé; Vilaseca, María Antonia; Campistol, Jaume; Briones, Paz; Pàmpols, Teresa; Salomons, Gajja S; Ribes, Antonia; Artuch, Rafael

2007-11-01

To report the prevalence of creatine transporter deficiency in males with mental retardation and to study whether a protein-rich food intake might be a potential diagnostic pitfall. We determined creatine/creatinine ratio in urine samples from 1600 unrelated male patients with mental retardation and/or autism. Urine creatine was analyzed by HPLC-MS/MS. Thirty-three of 1600 cases showed increased urine creatine/creatinine ratio. Four out of these thirty-three cases were definitively diagnosed with creatine transporter deficiency, while the other 29 were false positive results. Significantly higher values were observed for urine Cr/Crn ratio in healthy volunteers after a meal based on beef or oily fish as compared to eggs, pasta or salad (Wilcoxon test: p<0.005). False positive results may be observed in biochemical screening for creatine transporter deficiency, and they may be due to intake of meals rich in creatine prior to urine samples analysis.

[Screening for intellectual disability among adults].

PubMed

Søndenaa, Erik; Linaker, Olav; Bjørgen, Tale Gjertine; Nøttestad, Jim Aage

2010-08-12

Instigation of proper measures in case of intellectual disability is often conditioned by a diagnosis. Our aim was to assess whether the Hayes Ability Screening Index (HASI) is a suitable screening instrument for intellectual disability among adults. The article is based on three former studies aimed at validating HASI for use among patients referred for neuropsychological examination, prison inmates and psychiatric inpatients in community mental health centres. The sample consisted of 264 persons. The HASI correlated with the more comprehensive scales of assessing intellectual functioning (Wechsler tests) (r = 0.73, p < 0.001). With a cut-off value of 85, HASI had a sensitivity of 0.97 and a specificity of 0.61 in relation to an IQ < 70. HASI is associated with few false negatives, but a large number of false positives. This implies that an intellectual disability is concluded in too many cases; a positive screening should be followed up with a more thorough assessment.

Clinical experience with (/sup 111/ In) indium chloride scanning in inflammatory diseases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dayem, H.M.; Breen, J.; Leslie, E.V.

1978-05-01

Forty-eight patients were scanned with /sup 111/In-chloride in an attempt to identify the cause of fever. Fifteen true positive scans, 30 true negatives, and 3 false negatives were found. Of the 15 true positives, 7 cases of abdominal or pelvic abscess, and 8 cases of alcoholic hepatitis were detected. The 3 false negatives included: (1) an abscess in the anterior abdominal wall; (2) an abscess in the right upper quadrant at the site of a necrotic gallbladder; and (3) a tuberculous abscess of the lumbar spine. Examples from the different categories, pitfalls in interpretation and advantages and disadvantages of scanningmore » with /sup 111/In-chloride will be presented. These studies indicate that /sup 111/In-chloride is a safe, reliable scanning agent for abscesses below the diaphragm especially in patients who cannot undergo adequate bowel preparation.« less

Quality control in the diagnosis of Trichuris trichiura and Ascaris lumbricoides using the Kato-Katz technique: experience from three randomised controlled trials.

PubMed

Speich, Benjamin; Ali, Said M; Ame, Shaali M; Albonico, Marco; Utzinger, Jürg; Keiser, Jennifer

2015-02-05

An accurate diagnosis of soil-transmitted helminthiasis is important for individual patient management, for drug efficacy evaluation and for monitoring control programmes. The Kato-Katz technique is the most widely used method detecting soil-transmitted helminth eggs in faecal samples. However, detailed analyses of quality control, including false-positive and faecal egg count (FEC) estimates, have received little attention. Over a 3-year period, within the frame of a series of randomised controlled trials conducted in Pemba, United Republic of Tanzania, 10% of randomly selected Kato-Katz thick smears were re-read for Trichuris trichiura and Ascaris lumbricoides eggs. In case of discordant result (i.e. positive versus negative) the slides were re-examined a third time. A result was assumed to be false-positive or false-negative if the result from the initial reading did not agree with the quality control as well as the third reading. We also evaluated the general agreement in FECs between the first and second reading, according to internal and World Health Organization (WHO) guidelines. From the 1,445 Kato-Katz thick smears subjected to quality control, 1,181 (81.7%) were positive for T. trichiura and 290 (20.1%) were positive for A. lumbricoides. During quality control, very low rates of false-positive results were observed; 0.35% (n = 5) for T. trichiura and 0.28% (n = 4) for A. lumbricoides. False-negative readings of Kato-Katz thick smears were obtained in 28 (1.94%) and 6 (0.42%) instances for T. trichiura and A. lumbricoides, respectively. A high frequency of discordant results in FECs was observed (i.e. 10.0-23.9% for T. trichiura, and 9.0-11.4% for A. lumbricoides). Our analyses show that the rate of false-positive diagnoses of soil-transmitted helminths is low. As the probability of false-positive results increases after examination of multiple stool samples from a single individual, the potential influence of false-positive results on epidemiological studies and anthelminthic drug efficacy studies should be determined. Existing WHO guidelines for quality control might be overambitious and might have to be revised, specifically with regard to handling disagreements in FECs.

Comparison of Antigen Detection and Nested PCR in CSF Samples of HIV Positive and Negative Patients with Suspected Cryptococcal Meningitis in a Tertiary Care Hospital.

PubMed

Kumari, Sunita; Verma, Rajesh Kumar; Singh, Dharmendra Prasad; Yadav, Ramakant

2016-04-01

The cases of cryptococcal meningitis and other forms of cryptococcosis have increased in recent time and the present scenario of the condition with significant morbidity and mortality is actually posing a serious threat to the community, so an early and prompt diagnosis is necessary to prevent serious complications and thus improving the overall disease outcome. Comparison of diagnostic efficacy of nested Polymerase Chain Reaction (PCR) with Latex Agglutination Test (LAT) in the Cerebro Spinal Fluid (CSF) samples of the cases of meningitis in HIV positive and negative cases. We have compared the diagnostic efficacy of Latex Agglutination Test (LAT) with nested Polymerase Chain Reaction (PCR) in 200 Cerebrospinal Fluid (CSF) samples, including 14 HIV positive also, in the cases of suspected cryptococcal meningitis. Nested PCR was done in all cases reporting positive by LAT and results were then compared with that of India ink and culture on Sabouraud Dextrose Agar (SDA), and the isolates were further identified by urease, nitrate and sugar assimilation tests. Of the 200 cases, including 14 HIV positive, LAT was positive in 46 cases while 154 were negative. Out of these 46 LAT positive cases, nested PCR was positive in 40 cases only, while culture and India ink was positive in 38 and 33 cases respectively. Majority of the cases, 30 (65.2%) were between age group 21-50 years, while 2 (4.3%) in 0-20, and 14 (30.4%) in 51-80 years age group. Although negative staining like India ink and nigrosin are most widely used techniques, but these suffer with subjective error. Rapid method like LAT is available but it always has the scope of false positive and negative results. In such cases nested PCR can help in establishing final diagnosis.

Proportion hyperglycosylated hCG: a new test for discriminating gestational trophoblastic diseases.

PubMed

Cole, Laurence A

2014-11-01

Hyperglycosylated human chorionic gonadotropin (hCG) is a variant of hCG with large oligosaccharide side chains. Although hCG is produced by syncytiotrophoblast cells, hyperglycosylated hCG marks cytotrophoblast cell. Hyperglycosylated hCG signals placental implantation. Total hCG in serum and urine is measured by the Siemens Immulite hCG pregnancy test; the result is in milli-international unit per milliliter. Hyperglycosylated hCG is determined by the B152 microtiter plate assay; the result is in nanogram per milliliter. Hyperglycosylated hCG results can be converted to milli-international unit per milliliter equivalents by multiplying by 11. The test measures proportion hyperglycosylated hCG, hyperglycosylated hCG / total hCG. Proportion hyperglycosylated hCG marks cases intent on developing persistent hydatidiform mole (68% detection at 17% false detection). Proportion hyperglycosylated hCG also marks persistent hydatidiform mole (100% detection at 5.1% false detection). Proportion hyperglycosylated hCG distinguishes choriocarcinoma and gestational trophoblastic neoplasm cases, absolutely discriminating aggressive cases and minimally aggressive cases. Proportion hyperglycosylated hCG identifies quiescent gestational trophoblastic disease cases. It recognizes quiescent cases that become persistent disease (100% detection at 0% false positive). Proportion hyperglycosylated hCG is an invaluable test for discriminating gestational trophoblastic diseases.

The human false-negative rate of rescreening Pap tests. Measured in a two-arm prospective clinical trial.

PubMed

Renshaw, A A; Lezon, K M; Wilbur, D C

2001-04-25

Routine quality control rescreening often is used to calculate the false-negative rate (FNR) of gynecologic cytology. Theoretic analysis suggests that this is not appropriate, due to the high FNR of rescreening and the inability to actually measure it. The authors sought to determine the FNR of manual rescreening in a large, prospective, two-arm clinical trial using an analytic instrument in the evaluation. The results of the Autopap System Clinical Trial, encompassing 25,124 analyzed slides, were reviewed. The false-negative and false-positive rates at various thresholds were determined for routine primary screening, routine rescreening, Autopap primary screening, and Autopap rescreening by using a simple, standard methodology. The FNR of routine manual rescreening at the level of atypical squamous cells of undetermined significance (ASCUS) was 73%, more than 3 times the FNR of primary screening; 11 cases were detected. The FNR of Autopap rescreening was 34%; 80 cases were detected. Routine manual rescreening decreased the laboratory FNR by less than 1%; Autopap rescreening reduced the overall laboratory FNR by 5.7%. At the same time, the false-positive rate for Autopap screening was significantly less than that of routine manual screening at the ASCUS level (4.7% vs. 5.6%; P < 0.0001). Rescreening with the Autopap system remained more sensitive than manual rescreening at the low grade squamous intraepithelial lesions threshold (FNR of 58.8% vs. 100%, respectively), although the number of cases rescreened was low. Routine manual rescreening cannot be used to calculate the FNR of primary screening. Routine rescreening is an extremely ineffective method to detect error and thereby decrease a laboratory's FNR. The Autopap system is a much more effective way of detecting errors within a laboratory and reduces the laboratory's FNR by greater than 25%.

Using the genome aggregation database, computational pathogenicity prediction tools, and patch clamp heterologous expression studies to demote previously published long QT syndrome type 1 mutations from pathogenic to benign.

PubMed

Clemens, Daniel J; Lentino, Anne R; Kapplinger, Jamie D; Ye, Dan; Zhou, Wei; Tester, David J; Ackerman, Michael J

2018-04-01

Mutations in the KCNQ1-encoded Kv7.1 potassium channel cause long QT syndrome (LQTS) type 1 (LQT1). It has been suggested that ∼10%-20% of rare LQTS case-derived variants in the literature may have been published erroneously as LQT1-causative mutations and may be "false positives." The purpose of this study was to determine which previously published KCNQ1 case variants are likely false positives. A list of all published, case-derived KCNQ1 missense variants (MVs) was compiled. The occurrence of each MV within the Genome Aggregation Database (gnomAD) was assessed. Eight in silico tools were used to predict each variant's pathogenicity. Case-derived variants that were either (1) too frequently found in gnomAD or (2) absent in gnomAD but predicted to be pathogenic by ≤2 tools were considered potential false positives. Three of these variants were characterized functionally using whole-cell patch clamp technique. Overall, there were 244 KCNQ1 case-derived MVs. Of these, 29 (12%) were seen in ≥10 individuals in gnomAD and are demotable. However, 157 of 244 MVs (64%) were absent in gnomAD. Of these, 7 (4%) were predicted to be pathogenic by ≤2 tools, 3 of which we characterized functionally. There was no significant difference in current density between heterozygous KCNQ1-F127L, -P477L, or -L619M variant-containing channels compared to KCNQ1-WT. This study offers preliminary evidence for the demotion of 32 (13%) previously published LQT1 MVs. Of these, 29 were demoted because of their frequent sighting in gnomAD. Additionally, in silico analysis and in vitro functional studies have facilitated the demotion of 3 ultra-rare MVs (F127L, P477L, L619M). Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Ability of Ultrasonography in Detection of Different Extremity Bone Fractures; a Case Series Study

PubMed Central

Bozorgi, Farzad; Shayesteh Azar, Massoud; Montazer, Seyed Hossein; Chabra, Aroona; Heidari, Seyed Farshad; Khalilian, Alireza

2017-01-01

Introduction: Despite radiography being the gold standard in evaluation of orthopedic injuries, using bedside ultrasonography has several potential supremacies such as avoiding exposure to ionizing radiation, availability in pre-hospital settings, being extensively accessible, and ability to be used on the bedside. The aim of the present study is to evaluate the diagnostic accuracy of ultrasonography in detection of extremity bone fractures. Methods: This study is a case series study, which was prospectively conducted on multiple blunt trauma patients, who were 18 years old or older, had stable hemodynamic, Glasgow coma scale 15, and signs or symptoms of a possible extremity bone fracture. After initial assessment, ultrasonography of suspected bones was performed by a trained emergency medicine resident and prevalence of true positive and false negative findings were calculated compared to plain radiology. Results: 108 patients with the mean age of 44.6 ± 20.4 years were studied (67.6% male). Analysis was done on 158 sites of fracture, which were confirmed with plain radiography. 91 (57.6%) cases were suspected to have upper extremity fracture(s) and 67 (42.4%) to have lower ones. The most frequent site of injuries were forearm (36.7%) in upper limbs and leg (27.8%) in lower limbs. Prevalence of true positive and false negative cases for fractures detected by ultrasonography were 59 (64.8%) and 32 (35.52%) for upper and 49 (73.1%) and 18 (26.9%) for lower extremities, respectively. In addition, prevalence of true positive and false negative detected cases for intra-articular fractures were 24 (48%) and 26 (52%), respectively. Conclusion The present study shows the moderate sensitivity (68.3%) of ultrasonography in detection of different extremity bone fractures. Ultrasonography showed the best sensitivity in detection of femur (100%) and humerus (76.2%) fractures, respectively. It had low sensitivity in detection of in intra-articular fractures. PMID:28286822

Ability of Ultrasonography in Detection of Different Extremity Bone Fractures; a Case Series Study.

PubMed

Bozorgi, Farzad; Shayesteh Azar, Massoud; Montazer, Seyed Hossein; Chabra, Aroona; Heidari, Seyed Farshad; Khalilian, Alireza

2017-01-01

Despite radiography being the gold standard in evaluation of orthopedic injuries, using bedside ultrasonography has several potential supremacies such as avoiding exposure to ionizing radiation, availability in pre-hospital settings, being extensively accessible, and ability to be used on the bedside. The aim of the present study is to evaluate the diagnostic accuracy of ultrasonography in detection of extremity bone fractures. This study is a case series study, which was prospectively conducted on multiple blunt trauma patients, who were 18 years old or older, had stable hemodynamic, Glasgow coma scale 15, and signs or symptoms of a possible extremity bone fracture. After initial assessment, ultrasonography of suspected bones was performed by a trained emergency medicine resident and prevalence of true positive and false negative findings were calculated compared to plain radiology. 108 patients with the mean age of 44.6 ± 20.4 years were studied (67.6% male). Analysis was done on 158 sites of fracture, which were confirmed with plain radiography. 91 (57.6%) cases were suspected to have upper extremity fracture(s) and 67 (42.4%) to have lower ones. The most frequent site of injuries were forearm (36.7%) in upper limbs and leg (27.8%) in lower limbs. Prevalence of true positive and false negative cases for fractures detected by ultrasonography were 59 (64.8%) and 32 (35.52%) for upper and 49 (73.1%) and 18 (26.9%) for lower extremities, respectively. In addition, prevalence of true positive and false negative detected cases for intra-articular fractures were 24 (48%) and 26 (52%), respectively. The present study shows the moderate sensitivity (68.3%) of ultrasonography in detection of different extremity bone fractures. Ultrasonography showed the best sensitivity in detection of femur (100%) and humerus (76.2%) fractures, respectively. It had low sensitivity in detection of in intra-articular fractures.

False penile fracture: value of different diagnostic approaches and long-term outcome of conservative and surgical management.

PubMed

El-Assmy, Ahmed; El-Tholoth, Hossam S; Abou-El-Ghar, Mohamed E; Mohsen, Tarek; Ibrahiem, El Housseiny I

2010-06-01

We determined the value of clinical and radiological findings in diagnosis of false penile fracture. Also, the long-term outcome of conservative and surgical treatment of such patients was evaluated. Seventeen patients with false penile fracture were treated conservatively (3 patients) and surgically (14 patients) at our center. Medical records were retrospectively reviewed for etiology, symptoms, signs of physical examination, and information on findings of surgical exploration. Data on erectile function and penile sequelae were obtained during follow-up using the Sexual Health Inventory for Men (SHIM) questionnaire and local examination. The most common cause of false penile fracture is sexual intercourse (76.5%). False fracture was suspected in 3 patients who presented with small hematoma and slow post-trauma detumescence; intact tunicas were diagnosed by magnetic resonance imaging (MRI) in all of them and were managed conservatively. Surgical penile exploration was performed in 14 cases, in whom preoperative ultrasound was done in 6, and it was false positive for presence of tunical tear in 50%. Exploration revealed nonspecific dartos bleeding in 9 cases and avulsed superficial dorsal vein in 5. Long-term follow-up (mean=93 months) was available for 16 patients, among whom there was no complications. In most cases, false penile fracture is indistinguishable from true penile fracture either clinically or radiologically. In atypical cases, MRI seems to be a promising modality for diagnosis of such patients. The long-term outcome of conservative and surgical treatment is excellent. Copyright (c) 2010 Elsevier Inc. All rights reserved.

[Evaluation of fetomaternal hemorrhage in postpartum patients with indication for administration of anti-D immunoglobulin].

PubMed

Baiochi, Eduardo; Camano, Luiz; Bordin, José Orlando

2005-01-01

This study evaluated fetomaternal hemorrhage (FMH) in 343 postpartum patients who required prophylaxis of Rh alloimmunization with anti-D immunoglobulin. The rosette test was applied to screen for patients needing quantitative determination of fetal blood transferred from the maternal circulation, which was then measured by the Kleihauer-Betke test (K-B). The rosette test was positive in 22 cases (6.4%). In five of these cases, K-B did not show fetomaternal hemorrhage (a 1.45% false-positive rate for the rosette test), and in one case the test was inconclusive. There were 8 cases with FMH < 10 ml (2.3%), 6 cases with FMH from 10 to 30 ml (1.7%), and two cases with FMH > 30 ml (0.58%), requiring a supplementary dose of anti-D. The study concludes that following the rosette test, additional evaluation of FMH using a quantitative test was unnecessary in 93.6% of the cases.

Automatic abdominal lymph node detection method based on local intensity structure analysis from 3D x-ray CT images

NASA Astrophysics Data System (ADS)

Nakamura, Yoshihiko; Nimura, Yukitaka; Kitasaka, Takayuki; Mizuno, Shinji; Furukawa, Kazuhiro; Goto, Hidemi; Fujiwara, Michitaka; Misawa, Kazunari; Ito, Masaaki; Nawano, Shigeru; Mori, Kensaku

2013-03-01

This paper presents an automated method of abdominal lymph node detection to aid the preoperative diagnosis of abdominal cancer surgery. In abdominal cancer surgery, surgeons must resect not only tumors and metastases but also lymph nodes that might have a metastasis. This procedure is called lymphadenectomy or lymph node dissection. Insufficient lymphadenectomy carries a high risk for relapse. However, excessive resection decreases a patient's quality of life. Therefore, it is important to identify the location and the structure of lymph nodes to make a suitable surgical plan. The proposed method consists of candidate lymph node detection and false positive reduction. Candidate lymph nodes are detected using a multi-scale blob-like enhancement filter based on local intensity structure analysis. To reduce false positives, the proposed method uses a classifier based on support vector machine with the texture and shape information. The experimental results reveal that it detects 70.5% of the lymph nodes with 13.0 false positives per case.

A novel gamma-fitting statistical method for anti-drug antibody assays to establish assay cut points for data with non-normal distribution.

PubMed

Schlain, Brian; Amaravadi, Lakshmi; Donley, Jean; Wickramasekera, Ananda; Bennett, Donald; Subramanyam, Meena

2010-01-31

In recent years there has been growing recognition of the impact of anti-drug or anti-therapeutic antibodies (ADAs, ATAs) on the pharmacokinetic and pharmacodynamic behavior of the drug, which ultimately affects drug exposure and activity. These anti-drug antibodies can also impact safety of the therapeutic by inducing a range of reactions from hypersensitivity to neutralization of the activity of an endogenous protein. Assessments of immunogenicity, therefore, are critically dependent on the bioanalytical method used to test samples, in which a positive versus negative reactivity is determined by a statistically derived cut point based on the distribution of drug naïve samples. For non-normally distributed data, a novel gamma-fitting method for obtaining assay cut points is presented. Non-normal immunogenicity data distributions, which tend to be unimodal and positively skewed, can often be modeled by 3-parameter gamma fits. Under a gamma regime, gamma based cut points were found to be more accurate (closer to their targeted false positive rates) compared to normal or log-normal methods and more precise (smaller standard errors of cut point estimators) compared with the nonparametric percentile method. Under a gamma regime, normal theory based methods for estimating cut points targeting a 5% false positive rate were found in computer simulation experiments to have, on average, false positive rates ranging from 6.2 to 8.3% (or positive biases between +1.2 and +3.3%) with bias decreasing with the magnitude of the gamma shape parameter. The log-normal fits tended, on average, to underestimate false positive rates with negative biases as large a -2.3% with absolute bias decreasing with the shape parameter. These results were consistent with the well known fact that gamma distributions become less skewed and closer to a normal distribution as their shape parameters increase. Inflated false positive rates, especially in a screening assay, shifts the emphasis to confirm test results in a subsequent test (confirmatory assay). On the other hand, deflated false positive rates in the case of screening immunogenicity assays will not meet the minimum 5% false positive target as proposed in the immunogenicity assay guidance white papers. Copyright 2009 Elsevier B.V. All rights reserved.

Occupational exposure assessment of magnetic fields generated by induction heating equipment-the role of spatial averaging.

PubMed

Kos, Bor; Valič, Blaž; Kotnik, Tadej; Gajšek, Peter

2012-10-07

Induction heating equipment is a source of strong and nonhomogeneous magnetic fields, which can exceed occupational reference levels. We investigated a case of an induction tempering tunnel furnace. Measurements of the emitted magnetic flux density (B) were performed during its operation and used to validate a numerical model of the furnace. This model was used to compute the values of B and the induced in situ electric field (E) for 15 different body positions relative to the source. For each body position, the computed B values were used to determine their maximum and average values, using six spatial averaging schemes (9-285 averaging points) and two averaging algorithms (arithmetic mean and quadratic mean). Maximum and average B values were compared to the ICNIRP reference level, and E values to the ICNIRP basic restriction. Our results show that in nonhomogeneous fields, the maximum B is an overly conservative predictor of overexposure, as it yields many false positives. The average B yielded fewer false positives, but as the number of averaging points increased, false negatives emerged. The most reliable averaging schemes were obtained for averaging over the torso with quadratic averaging, with no false negatives even for the maximum number of averaging points investigated.

False-positive diagnosis of disease progression by magnetic resonance imaging for response assessment in prostate cancer with bone metastases: A case report and review of the pitfalls of images in the literature

PubMed Central

YU, YI-SHAN; LI, WAN-HU; LI, MING-HUAN; MENG, XUE; KONG, LI; YU, JIN-MING

2015-01-01

Bone metastases are common in prostate cancer. However, differentiating neoplastic from non-neoplastic alterations of bone on images is challenging. In the present report, a rare case of bone marrow reconversion on magnetic resonance imaging (MRI) assessment, which may lead to a false-positive diagnosis of disease progression of bone metastases in hormone-resistant prostate cancer, is presented. Furthermore, a review of the literature regarding the pitfalls of images for response assessment, including the ‘flare’ phenomenon on bone scintigraphy, computed tomography (CT), positron emission tomography/CT and marrow reconversion on MRI is also provided. These inaccuracies, which may lead to a premature termination of an efficacious treatment, should be carefully considered by the radiologists and oncologists involved in clinical trials. The case reported in the present study showed how to assess the early therapeutic response and select the appropriate treatment for the patient when these pitfalls are encountered on clinical images. PMID:26788174

Decision Making for Borderline Cases in Pass/Fail Clinical Anatomy Courses: The Practical Value of the Standard Error of Measurement and Likelihood Ratio in a Diagnostic Test

ERIC Educational Resources Information Center

Severo, Milton; Silva-Pereira, Fernanda; Ferreira, Maria Amelia

2013-01-01

Several studies have shown that the standard error of measurement (SEM) can be used as an additional “safety net” to reduce the frequency of false-positive or false-negative student grading classifications. Practical examinations in clinical anatomy are often used as diagnostic tests to admit students to course final examinations. The aim of this…

Performance characteristics of broth-only cultures after revision total joint arthroplasty.

PubMed

Smith, Eric B; Cai, Jenny; Wynne, Rachael; Maltenfort, Mitchell; Good, Robert P

2014-11-01

Surgeons frequently obtain intraoperative cultures at the time of revision total joint arthroplasty. The use of broth or liquid medium before applying the sample to the agar medium may be associated with contamination and false-positive cultures; however, the degree to which this is the case is not known. We (1) calculated the performance characteristics of broth-only cultures (sensitivity, specificity, positive predictive value, and negative predictive value) and (2) characterized the organisms identified in broth to determine whether a specific organism showed increased proclivity for true-positive periprosthetic joint infection (PJI). A single-institution retrospective chart review was performed on 257 revision total joint arthroplasties from 2009 through 2010. One hundred ninety (74%) had cultures for review. All culture results, as well as treatment, if any, were documented and patients were followed for a minimum of 1 year for evidence of PJI. Cultures were measured as either positive from the broth only or broth negative. The true diagnosis of infection was determined by the Musculoskeletal Infection Society criteria during the preoperative workup or postoperatively at 1 year for purposes of calculating the performance characteristics of the broth-only culture. The sensitivity, specificity, positive predictive value, and negative predictive value were 19%, 88%, 13%, and 92%, respectively. The most common organism identified was coagulase-negative Staphylococcus (16 of 24 cases, 67%). Coagulase-negative Staphylococcus was present in all three true-positive cases; however, it was also found in 13 of the false-positive cases. The broth-only positive cultures showed poor sensitivity and positive predictive value but good specificity and negative predictive value. The good specificity indicates that it can help to rule in the presence of PJI; however, the poor sensitivity makes broth-only culture an unreliable screening test. We recommend that broth-only culture results be carefully scrutinized and decisions on the diagnosis and treatment of infection should be based specifically on the Musculoskeletal Infection Society criteria. Level IV, diagnostic study. See Instructions for Authors for a complete description of levels of evidence.

The comparative performance of PMI estimation in skeletal remains by three methods (C-14, luminol test and OHI): analysis of 20 cases.

PubMed

Cappella, Annalisa; Gibelli, Daniele; Muccino, Enrico; Scarpulla, Valentina; Cerutti, Elisa; Caruso, Valentina; Sguazza, Emanuela; Mazzarelli, Debora; Cattaneo, Cristina

2015-01-27

When estimating post-mortem interval (PMI) in forensic anthropology, the only method able to give an unambiguous result is the analysis of C-14, although the procedure is expensive. Other methods, such as luminol tests and histological analysis, can be performed as preliminary investigations and may allow the operators to gain a preliminary indication concerning PMI, but they lack scientific verification, although luminol testing has been somewhat more accredited in the past few years. Such methods in fact may provide some help as they are inexpensive and can give a fast response, especially in the phase of preliminary investigations. In this study, 20 court cases of human skeletonized remains were dated by the C-14 method. For two cases, results were chronologically set after the 1950s; for one case, the analysis was not possible technically. The remaining 17 cases showed an archaeological or historical collocation. The same bone samples were also screened with histological examination and with the luminol test. Results showed that only four cases gave a positivity to luminol and a high Oxford Histology Index (OHI) score at the same time: among these, two cases were dated as recent by the radiocarbon analysis. Thus, only two false-positive results were given by the combination of these methods and no false negatives. Thus, the combination of two qualitative methods (luminol test and microscopic analysis) may represent a promising solution to cases where many fragments need to be quickly tested.

Cross-Reactivity of Pantoprazole with Three Commercial Cannabinoids Immunoassays in Urine.

PubMed

Gomila, Isabel; Barceló, Bernardino; Rosell, Antonio; Avella, Sonia; Sahuquillo, Laura; Dastis, Macarena

2017-11-01

Pantoprazole is a frequently prescribed proton pump inhibitor (PPI) commonly utilized in the management of gastrointestinal symptoms. Few substances have proved to cause a false-positive cannabinoid urine screen. However, a case of false-positive urine cannabinoid screen in a patient who received a pantoprazole dose has been recently published. The purpose of this study was to determine the potential cross-reactivity of pantoprazole in the cannabinoid immunoassays: Alere Triage® TOX Drug Screen, KIMS® Cannabinoids II and DRI® Cannabinoids Assay. Drug-free urine to which pantoprazole was added up to 12,000 μg/mL produced negative results in the DRI® Cannabinoids and KIMS® Cannabinoids II. Alere Triage® TOX Drug Screen assay gave positive results at pantoprazole concentrations higher than 1,000 μg/mL. Urine samples from 8 pediatric patients were collected at the beginning of their pantoprazole treatment. Alere Triage® TOX Drug Screen assay produced positive test results in all patient samples and KIMS® Cannabinoids II immunoassay produced positive test results in one patient sample. None patient sample gave a false-positive result when analyzed by the DRI® Cannabinoids Assay. Our findings demonstrate that some cannabinoids immunoassays are susceptible to cross-reaction errors resulting from the presence in urine of pantoprazole and the resulting metabolism of the parent drug. Clinicians should be aware of the possibility of false-positive results for cannabinoids after a pantoprazole treatment. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Zero risk tolerance costs lives: loss of transplantable organs due to human immunodeficiency virus nucleic acid testing of potential donors.

PubMed

Shafer, Teresa J; Schkade, David; Schkade, Lawrence; Geier, Steven S; Orlowski, Jeffrey P; Klintmalm, Goran

2011-09-01

Patients' deaths due to the organ donor shortage make it imperative that every suitable organ be transplanted. False-positive results of tests for infection with the human immunodeficiency virus (HIV) result in lost organs. A survey of US organ procurement organizations collected the numbers of donors and ruled-out potential donors who had a positive result on an HIV test from January 1,2006, to October 31, 2008. Sixty-two percent of US organ procurement organizations participated. Of the 12397 donor/nondonor cases, 56 (0.45%) had an initial positive result on an HIV antibody or HIV nucleic acid test, and only 8 (14.3%) of those were confirmed positive. Of the false-positive results, 50% were from HIV antibody tests and 50% were from HIV nucleic acid tests. Organs are a scarce, finite, and perishable resource. Use of HIV antibody testing has produced a remarkably safe track record of avoiding HIV transmission, with 22 years of nonoccurrence between transmissions. Because false positives occur with any test, including the HIV Ab test, adding nucleic acid testing to the standard donor testing panel doubles the number of false-positive HIV test results and thus the number of medically suitable donors lost. The required HIV antibody test is 99.99% effective in preventing transmission of the HIV virus. Adding the HIV nucleic acid test to routine organ donor screening could result in as many as 761 to 1551 unnecessary deaths of patients between HIV transmission events because medically suitable organs are wasted.

High hepatitis B seroprevalence and risk factors for infection in pregnant women on the Thailand-Myanmar Border.

PubMed

Banks, Tristan; Kang, Joy; Watts, Isabella; Tyrosvoutis, Mary Ellen G; Min, Aung Myat; Tun, Nay Win; Keereecharoen, Lily; Simmawong, Wiriya; Wanyatip, Sunaree; Hanboonkunupakarn, Borimas; Nosten, François; McGready, Rose

2016-04-28

Infection from Hepatitis B primarily results from peri-partum vertical transmission and the risk increases in the presence of hepatitis B e antigen. We aimed to evaluate a new screening program for hepatitis B in pregnant women as a component of antenatal services in a marginalized population. Counseling and screening for hepatitis B screening was offered to all women at the first visit, at Shoklo Malaria Research Unit (SMRU) antenatal clinics on the Thai-Myanmar border.  Point-of-care rapid diagnostic tests (RDT) were used throughout the period of evaluation. A certified Thai Public Health laboratory at Mae Sot Hospital verified RDT positive cases using enzyme-linked immunosorbent assay (ELISA) for HBsAb and HBeAg. Risk factors for hepatitis B were identified by data linkage to antenatal care records. There were 523 (8.5%) RDT positive for HBsAg among 6158 women tested (Aug-2012 to April-2014). Of these 373 (96.9%) of 385 sent for confirmation were positive by ELISA i.e. RDT false positive rate of 3.1% (95% CI 1.7- 5.4). The overall confirmed HbsAg prevalence was 8.3% (511/6158) (95% CI 7.6-9.0). HBeAg prevalence was 32.7% (114/350) (95% CI 27.9-37.7) of cases tested. Risk factors for HBsAg positivity included age >25 years (OR 1.24, CI 1.03-1.49, p 0.021) and Karen heritage (OR 1.73, CI 1.39-2.15, p < 0.01). High hepatitis B seroprevalence amongst migrants and refugees accessing SMRU antenatal services likely reflects that of Kayin State, Myanmar, and perinatal prevention programs are required. False positive cases with HBsAg RDT complicate what is theoretically a straightforward screening.

TU-G-204-09: The Effects of Reduced- Dose Lung Cancer Screening CT On Lung Nodule Detection Using a CAD Algorithm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, S; Lo, P; Kim, G

2015-06-15

Purpose: While Lung Cancer Screening CT is being performed at low doses, the purpose of this study was to investigate the effects of further reducing dose on the performance of a CAD nodule-detection algorithm. Methods: We selected 50 cases from our local database of National Lung Screening Trial (NLST) patients for which we had both the image series and the raw CT data from the original scans. All scans were acquired with fixed mAs (25 for standard-sized patients, 40 for large patients) on a 64-slice scanner (Sensation 64, Siemens Healthcare). All images were reconstructed with 1-mm slice thickness, B50 kernel.more » 10 of the cases had at least one nodule reported on the NLST reader forms. Based on a previously-published technique, we added noise to the raw data to simulate reduced-dose versions of each case at 50% and 25% of the original NLST dose (i.e. approximately 1.0 and 0.5 mGy CTDIvol). For each case at each dose level, the CAD detection algorithm was run and nodules greater than 4 mm in diameter were reported. These CAD results were compared to “truth”, defined as the approximate nodule centroids from the NLST reports. Subject-level mean sensitivities and false-positive rates were calculated for each dose level. Results: The mean sensitivities of the CAD algorithm were 35% at the original dose, 20% at 50% dose, and 42.5% at 25% dose. The false-positive rates, in decreasing-dose order, were 3.7, 2.9, and 10 per case. In certain cases, particularly in larger patients, there were severe photon-starvation artifacts, especially in the apical region due to the high-attenuating shoulders. Conclusion: The detection task was challenging for the CAD algorithm at all dose levels, including the original NLST dose. However, the false-positive rate at 25% dose approximately tripled, suggesting a loss of CAD robustness somewhere between 0.5 and 1.0 mGy. NCI grant U01 CA181156 (Quantitative Imaging Network); Tobacco Related Disease Research Project grant 22RT-0131.« less

Sensitivity and specificity of oral HPV detection for HPV-positive head and neck cancer.

PubMed

Gipson, Brooke J; Robbins, Hilary A; Fakhry, Carole; D'Souza, Gypsyamber

2018-02-01

The incidence of HPV-related head and neck squamous cell carcinoma (HPV-HNSCC) is increasing. Oral samples are easy and non-invasive to collect, but the diagnostic accuracy of oral HPV detection methods for classifying HPV-positive HNSCC tumors has not been well explored. In a systematic review, we identified eight studies of HNSCC patients meeting our eligibility criteria of having: (1) HPV detection in oral rinse or oral swab samples, (2) tumor HPV or p16 testing, (3) a publication date within the last 10 years (January 2007-May 2017, as laboratory methods change), and (4) at least 15 HNSCC cases. Data were abstracted from each study and a meta-analysis performed to calculate sensitivity and specificity. Eight articles meeting inclusion criteria were identified. Among people diagnosed with HNSCC, oral HPV detection has good specificity (92%, 95% CI = 82-97%) and moderate sensitivity (72%, 95% CI = 45-89%) for HPV-positive HNSCC tumor. Results were similar when restricted to studies with only oropharyngeal cancer cases, with oral rinse samples, or testing for HPV16 DNA (instead of any oncogenic HPV) in the oral samples. Among those who already have HNSCC, oral HPV detection has few false-positives but may miss one-half to one-quarter of HPV-related cases (false-negatives). Given these findings in cancer patients, the utility of oral rinses and swabs as screening tests for HPV-HNSCC among healthy populations is probably limited. Copyright © 2017 Elsevier Ltd. All rights reserved.

Predicting the severity of motor neuron disease progression using electronic health record data with a cloud computing Big Data approach.

PubMed

Ko, Kyung Dae; El-Ghazawi, Tarek; Kim, Dongkyu; Morizono, Hiroki

2014-05-01

Motor neuron diseases (MNDs) are a class of progressive neurological diseases that damage the motor neurons. An accurate diagnosis is important for the treatment of patients with MNDs because there is no standard cure for the MNDs. However, the rates of false positive and false negative diagnoses are still very high in this class of diseases. In the case of Amyotrophic Lateral Sclerosis (ALS), current estimates indicate 10% of diagnoses are false-positives, while 44% appear to be false negatives. In this study, we developed a new methodology to profile specific medical information from patient medical records for predicting the progression of motor neuron diseases. We implemented a system using Hbase and the Random forest classifier of Apache Mahout to profile medical records provided by the Pooled Resource Open-Access ALS Clinical Trials Database (PRO-ACT) site, and we achieved 66% accuracy in the prediction of ALS progress.

Microscopic diagnosis of vulvovaginal candidiasis in stained vaginal smears by Dutch general practitioners.

PubMed

Engberts, Marian K; Goedbloed, Annelize F; van Haaften, Maarten; van Haaften, Mathilde; Boon, Mathilde E; Boon, Maarten E; Heintz, Peter M

2007-01-01

To determine the accuracy of the microscopic diagnosis of vulvovaginal candidiasis (presence of [pseudo] hyphae and blastospores) in stained vaginal smears in clinical practice. General practitioners trained in diagnosing vulvovaginal candidiasis performed microscopy of 324 stained vaginal smears. These smears were sent to the pathologist for confirmation of the microscopic diagnosis of the clinician; cytologic diagnosis by the pathologist was considered the gold standard. In 104 of the 342 cases Candida was established by the pathologist. The clinicians made 24 false positive and 50 false negative diagnoses of Candida. Sensitivity and specificity of the microscopic diagnoses of the clinicians were 52% and 89%, respectively. The most frequent reason for a false positive diagnosis was presence of hairs, whereas the most frequent reason for a false negative diagnosis was understaining of the smear. This study shows that even in stained smears it is difficult for clinicians to recognize blastospores and (pseudo)hyphae. Efforts are clearly needed to improve the quality of the clinical diagnosis of vulvovaginal candidiasis.

Impact of SurePath® liquid-based preparation in cytological analysis of peritoneal washing in practice of gynecologic oncology

PubMed Central

Tyagi, Ruchita; Gupta, Nalini; Bhagat, Priyanka; Gainder, Shalini; Rai, Bhavna; Dhaliwal, L K; Rajwanshi, Arvind

2017-01-01

Context: Peritoneal washing is performed for staging of gynecologic tumors to detect subclinical intraperitoneal metastases. Aim: The aim of the present study was to assess the impact of SurePath™ liquid-based cytology (LBC) in peritoneal washing in various gynecological malignancies. Settings and Design: An audit of peritoneal-fluid/washing (January 2012 to July 2013) was performed with corresponding gynecologic specimens. All peritoneal washings were processed using both conventional and LBC technique. Suspicious cases on cytology were reported along with gynecologic specimens. Results: There were a total of 393 peritoneal fluids. Eighty-three (21.1%) were positive for malignancy, and the corresponding histology was available in 352 (89.6%) cases. Sixty-nine positive samples had ovarian malignancies and 5 had uterine causes. There were 9 cases of peritoneal washings in which no histopathology was available. The most common cause of positive peritoneal cytology was ovarian serous carcinoma in 55/84 (65.5%) cases. Other causes included mucinous cystadenocarcinoma, dysgerminoma, squamous cell carcinoma in teratoma, yolk sac tumor, and granulosa cell tumor. Uterine causes included 2/45 (4.4%) cases of endometrioid adenocarcinoma, ¼ (25%) cases of clear cell carcinoma, ½ (50%) cases of carcinosarcoma, and ¼ (25%) cervix carcinoma. On review of positive cases (n = 83), 10 cases were identified, which had nil (n = 4) to low cellularity (<3 tumor clusters/smear; n = 6) on conventional smears, and were confirmed malignant on LBC. Conclusions: The most common ovarian malignancy causing positive peritoneal cytology is papillary serous carcinoma. Endometrioid adenocarcinoma rarely leads to positive peritoneal cytology. LBC technique leads to concentration of tumor cells causing reduction in false negative cases, especially in hemorrhagic and low-cellular cases. PMID:28469317

Neisseria-Avoiding the Jump to Conclusions

ERIC Educational Resources Information Center

Spivey, Maria I.; Paschall, Robert T.; Ferrett, Rhonda; Alexander, Randell

2011-01-01

"Neisseria gonorrhoeae" infection in a prepubertal child is virtually diagnostic of sexual abuse, provided perinatal infection has been excluded. Therefore, it is imperative that "Neisseria gonorrhoeae" be correctly identified. We present two cases of false positive "Neisseria gonorrhoeae" meningitis encountered at two different children's…

Sociopathic Knowledge Bases: Correct Knowledge Can Be Harmful Even Given Unlimited Computation

DTIC Science & Technology

1989-08-01

pobitive, as false positives generated by a medical program can often be caught by a physician upon further testing . False negatives, however, may be...improvement over the knowledge base tested is obtained. Although our work is pretty much theoretical research oriented one example of ex- periments is...knowledge base, improves the performance by about 10%. of tests . First, we divide the cases into a training set and a validation set with 70% vs. 30% each

Evaluation of the light scattering and the turbidity microtiter plate-based methods for the detection of the excipient-mediated drug precipitation inhibition.

PubMed

Petruševska, Marija; Urleb, Uroš; Peternel, Luka

2013-11-01

The excipient-mediated precipitation inhibition is classically determined by the quantification of the dissolved compound in the solution. In this study, two alternative approaches were evaluated, one is the light scattering (nephelometer) and other is the turbidity (plate reader) microtiter plate-based methods which are based on the quantification of the compound precipitate. Following the optimization of the nephelometer settings (beam focus, laser gain) and the experimental conditions, the screening of 23 excipients on the precipitation inhibition of poorly soluble fenofibrate and dipyridamole was performed. The light scattering method resulted in excellent correlation (r>0.91) between the calculated precipitation inhibitor parameters (PIPs) and the precipitation inhibition index (PI(classical)) obtained by the classical approach for fenofibrate and dipyridamole. Among the evaluated PIPs AUC100 (nephelometer) resulted in only four false positives and lack of false negatives. In the case of the turbidity-based method a good correlation of the PI(classical) was obtained for the PIP maximal optical density (OD(max), r=0.91), however, only for fenofibrate. In the case of the OD(max) (plate reader) five false positives and two false negatives were identified. In conclusion, the light scattering-based method outperformed the turbidity-based one and could be reliably used for identification of novel precipitation inhibitors. Copyright © 2013 Elsevier B.V. All rights reserved.

Enhancement in sample collection for the detection of MDMA using a novel planar SPME (PSPME) device coupled to ion mobility spectrometry (IMS).

PubMed

Gura, Sigalit; Guerra-Diaz, Patricia; Lai, Hanh; Almirall, José R

2009-07-01

Trace detection of illicit drugs challenges the scientific community to develop improved sensitivity and selectivity in sampling and detection techniques. Ion mobility spectrometry (IMS) is one of the prominent trace detectors for illicit drugs and explosives, mostly due to its portability, high sensitivity and fast analysis. Current sampling methods for IMS rely on wiping suspected surfaces or withdrawing air through filters to collect particulates. These methods depend greatly on the particulates being bound onto surfaces or having sufficient vapour pressure to be airborne. Many of these compounds are not readily available in the headspace due to their low vapour pressure. This research presents a novel SPME device for enhanced air sampling and shows the use of optimized IMS by genetic algorithms to target volatile markers and/or odour signatures of illicit substances. The sampling method was based on unique static samplers, planar substrates coated with sol-gel polydimethyl siloxane (PDMS) nanoparticles, also known as planar solid-phase microextraction (PSPME). Due to its surface chemistry, high surface area and capacity, PSPME provides significant increases in sensitivity over conventional fibre SPME. The results show a 50-400 times increase in the detection capacity for piperonal, the odour signature of 3,4-methylenedioxymethamphetamine (MDMA). The PSPME-IMS technique was able to detect 600 ng of piperonal in a 30 s extraction from a quart-sized can containing 5 MDMA tablets, while detection using fibre SPME-IMS was not attainable. In a blind study of six cases suspected to contain varying amounts of MDMA in the tablets, PSPME-IMS successfully detected five positive cases and also produced no false positives or false negatives. One positive case had minimal amounts of MDMA resulting in a false negative response for fibre SPME-IMS.

Outbreak or illusion: consequences of 'improved' diagnostics for gonorrhoea.

PubMed

Bennett, Amy; Jeffery, Katie; O'Neill, Eunan; Sherrard, Jackie

2017-06-01

The sexual health service in Oxford introduced gonorrhoea nucleic amplification acid testing using the BD Viper XTR™ System. For practical reasons, a confirmatory nucleic amplification acid testing using a different platform was not used initially. Following the introduction of nucleic amplification acid testing, the rates of gonorrhoea increased threefold. Concerns were raised that this increase represented an outbreak. A retrospective review of cases over six months suggested that there may have been a number of false-positive results. A prospective study was then undertaken over six months, where all gonorrhoea positive samples were sent for confirmatory testing. This evaluation of all gonorrhoea cases in an English county found that the overall presumptive false-positive rates for gonorrhoea nucleic amplification acid testing using BD Viper XTR™ in our population are significant at 27% of female samples, 13.2% of heterosexual male samples, 3.5% of anogenital multiple site men who have sex with men samples and 62.8% of pharyngeal only men who have sex with men samples. The data demonstrate the need for confirmatory testing using a second nucleic acid target, as per BASHH/Public Health England guidelines, especially in low-prevalence settings and extragenital sites, due to cross-reactivity with commensal Neisseria species and low positive predictive values.

Rubella Surveillance and Diagnostic Testing among a Low-Prevalence Population, New York City, 2012–2013

PubMed Central

Zucker, Jane R.; Giancotti, Francesca R.; Abernathy, Emily; Icenogle, Joseph; Rakeman, Jennifer L.; Rosen, Jennifer B.

2017-01-01

ABSTRACT The New York City Department of Health and Mental Hygiene (DOHMH) receives clinical and laboratory reports for rubella. Because rubella immunoglobulin M (IgM) assays may produce false-positive results and rubella infections may be asymptomatic, interpretation of positive IgM results can be challenging. Rubella reports received by DOHMH in 2012 to 2013 were reviewed. The rubella IgM testing purpose was determined through case investigation. Results of IgM testing by indirect enzyme-linked immunosorbent assay (ELISA) and capture enzyme immunoassay (EIA) were compared to determine positive predictive value (PPV) and specificity. DOHMH received 199 rubella reports; 2 were true cases. Of all reports, 77.9% were tested for rubella IgM erroneously, 19.6% were tested for diagnostic purposes, 2.0% had unknown test purpose, and 0.5% were not tested. PPV of indirect ELISA was 6% overall, 14% for diagnostic tests, and 0% for tests ordered erroneously. PPV of capture EIA was 29% overall, 50% for diagnostic tests, and 0% for tests ordered erroneously. Overall, specificity was 52% for indirect ELISA and 85% for capture EIA. Limiting rubella IgM testing to patients for whom rubella diagnosis is suspected and using a more specific IgM assay have the potential to reduce false-positive rubella IgM results. PMID:28701468

Steroid profiling for congenital adrenal hyperplasia by tandem mass spectrometry as a second-tier test reduces follow-up burdens in a tertiary care hospital: a retrospective and prospective evaluation.

PubMed

Seo, Ja Young; Park, Hyung-Doo; Kim, Jong Won; Oh, Hyeon Ju; Yang, Jeong Soo; Chang, Yun Sil; Park, Won Soon; Lee, Soo-Youn

2014-01-01

Newborn screening for congenital adrenal hyperplasia (CAH) based on measuring 17-hydroxyprogesterone (17-OHP) by immunoassay generates a number of false-positive results, especially in preterm neonates. We applied steroid profiling by using liquid chromatography-tandem mass spectrometry (LC-MS/MS) as a second-tier test in newborns with positive CAH screening and evaluated its clinical utility in a tertiary care hospital setting. By performing a 4-year retrospective data review, we were able to test 121 dried blood spots from newborns with positive CAH screening for 17-OHP, androstenedione and cortisol levels by LC-MS/MS. We prospectively evaluated the clinical utility of steroid profiling after the implementation of steroid profiling as a second-tier test in our routine clinical practice. During the 2-year prospective study period, 104 cases with positive initial screening by FIA were tested by LC-MS/MS. Clinical and laboratory follow-up were performed for at least 6 months. The preterm neonates accounted for 50.7% (76/150) and 70.4% (88/125) of screening-positive cases in retrospective and prospective cohorts, respectively. By applying steroid profiling as a second-tier test for positive CAH screening, we eliminated all false-positive results and decreased the median follow-up time from 75 to 8 days. Our data showed that steroid profiling reduced the burden of follow-up exams by improving the positive predictive value of the CAH screening program. The use of steroid profiling as a second-tier test for positive CAH screening will improve clinical practice particularly in a tertiary care hospital setting where positive CAH screening from preterm neonates is frequently encountered.

Heidelberg Retina Tomography Analysis in Optic Disks with Anatomic Particularities

PubMed Central

Alexandrescu, C; Pascu, R; Ilinca, R; Popescu, V; Ciuluvica, R; Voinea, L; Celea, C

2010-01-01

Due to its objectivity, reproducibility and predictive value confirmed by many large scale statistical clinical studies, Heidelberg Retina Tomography has become one of the most used computerized image analysis of the optic disc in glaucoma. It has been signaled, though, that the diagnostic value of Moorfieds Regression Analyses and Glaucoma Probability Score decreases when analyzing optic discs with extreme sizes. The number of false positive results increases in cases of megalopapilllae and the number of false negative results increases in cases of small size optic discs. The present paper is a review of the aspects one should take into account when analyzing a HRT result of an optic disc with anatomic particularities. PMID:21254731

Maternal biochemical serum screening for Down syndrome in pregnancy with human immunodeficiency virus infection.

PubMed

Le Meaux, Jean-Patrick; Tsatsaris, Vassilis; Schmitz, Thomas; Fulla, Yvonne; Launay, Odile; Goffinet, François; Azria, Elie

2008-08-01

To estimate the influence of human immunodeficiency virus (HIV) infection and antiretroviral therapy on maternal serum markers levels and the false-positive rate with biochemical maternal serum screening for Down syndrome. We performed a 1:1 matched case-control study comparing 132 HIV-infected women with single pregnancy to controls selected among non-HIV-infected women matched on geographical origin and fetal sex. Of HIV-infected women, 47.7% were receiving antiretroviral therapy. Groups did not differ in multiples of the median (MoM) levels of total human chorionic gonadotrophin. The MoM alpha fetoprotein level did not differ between total HIV-infected women and control women but was significantly lower for untreated HIV-positive women compared with control women (0.91 compared with 1.03 MoM, P<.01) and compared with treated HIV-positive women (0.91 compared with 1.18 MoM, P<.01). The false-positive rate of biochemical screening did not differ between groups. Untreated HIV infection is associated with lower maternal serum alpha fetoprotein levels. Nevertheless, the false-positive rate of double-marker second-trimester Down syndrome serum screening did not appear to be affected in our sample of HIV-infected women, whether women were receiving antiretroviral therapy at the time of the test or not.

Plausibility assessment of a 2-state self-paced mental task-based BCI using the no-control performance analysis.

PubMed

Faradji, Farhad; Ward, Rabab K; Birch, Gary E

2009-06-15

The feasibility of having a self-paced brain-computer interface (BCI) based on mental tasks is investigated. The EEG signals of four subjects performing five mental tasks each are used in the design of a 2-state self-paced BCI. The output of the BCI should only be activated when the subject performs a specific mental task and should remain inactive otherwise. For each subject and each task, the feature coefficient and the classifier that yield the best performance are selected, using the autoregressive coefficients as the features. The classifier with a zero false positive rate and the highest true positive rate is selected as the best classifier. The classifiers tested include: linear discriminant analysis, quadratic discriminant analysis, Mahalanobis discriminant analysis, support vector machine, and radial basis function neural network. The results show that: (1) some classifiers obtained the desired zero false positive rate; (2) the linear discriminant analysis classifier does not yield acceptable performance; (3) the quadratic discriminant analysis classifier outperforms the Mahalanobis discriminant analysis classifier and performs almost as well as the radial basis function neural network; and (4) the support vector machine classifier has the highest true positive rates but unfortunately has nonzero false positive rates in most cases.

Automated detection of retinal nerve fiber layer defects on fundus images: false positive reduction based on vessel likelihood

NASA Astrophysics Data System (ADS)

Muramatsu, Chisako; Ishida, Kyoko; Sawada, Akira; Hatanaka, Yuji; Yamamoto, Tetsuya; Fujita, Hiroshi

2016-03-01

Early detection of glaucoma is important to slow down or cease progression of the disease and for preventing total blindness. We have previously proposed an automated scheme for detection of retinal nerve fiber layer defect (NFLD), which is one of the early signs of glaucoma observed on retinal fundus images. In this study, a new multi-step detection scheme was included to improve detection of subtle and narrow NFLDs. In addition, new features were added to distinguish between NFLDs and blood vessels, which are frequent sites of false positives (FPs). The result was evaluated with a new test dataset consisted of 261 cases, including 130 cases with NFLDs. Using the proposed method, the initial detection rate was improved from 82% to 98%. At the sensitivity of 80%, the number of FPs per image was reduced from 4.25 to 1.36. The result indicates the potential usefulness of the proposed method for early detection of glaucoma.

Biases in detection of apparent “weekend effect” on outcome with administrative coding data: population based study of stroke

PubMed Central

Li, Linxin

2016-01-01

Objectives To determine the accuracy of coding of admissions for stroke on weekdays versus weekends and any impact on apparent outcome. Design Prospective population based stroke incidence study and a scoping review of previous studies of weekend effects in stroke. Setting Primary and secondary care of all individuals registered with nine general practices in Oxfordshire, United Kingdom (OXVASC, the Oxford Vascular Study). Participants All patients with clinically confirmed acute stroke in OXVASC identified with multiple overlapping methods of ascertainment in 2002-14 versus all acute stroke admissions identified by hospital diagnostic and mortality coding alone during the same period. Main outcomes measures Accuracy of administrative coding data for all patients with confirmed stroke admitted to hospital in OXVASC. Difference between rates of “false positive” or “false negative” coding for weekday and weekend admissions. Impact of inaccurate coding on apparent case fatality at 30 days in weekday versus weekend admissions. Weekend effects on outcomes in patients with confirmed stroke admitted to hospital in OXVASC and impacts of other potential biases compared with those in the scoping review. Results Among 92 728 study population, 2373 episodes of acute stroke were ascertained in OXVASC, of which 826 (34.8%) mainly minor events were managed without hospital admission, 60 (2.5%) occurred out of the area or abroad, and 195 (8.2%) occurred in hospital during an admission for a different reason. Of 1292 local hospital admissions for acute stroke, 973 (75.3%) were correctly identified by administrative coding. There was no bias in distribution of weekend versus weekday admission of the 319 strokes missed by coding. Of 1693 admissions for stroke identified by coding, 1055 (62.3%) were confirmed to be acute strokes after case adjudication. Among the 638 false positive coded cases, patients were more likely to be admitted on weekdays than at weekends (536 (41.0%) v 102 (26.5%); P<0.001), partly because of weekday elective admissions after previous stroke being miscoded as new stroke episodes (267 (49.8%) v 26 (25.5%); P<0.001). The 30 day case fatality after these elective admissions was lower than after confirmed acute stroke admissions (11 (3.8%) v 233 (22.1%); P<0.001). Consequently, relative 30 day case fatality for weekend versus weekday admissions differed (P<0.001) between correctly coded acute stroke admissions and false positive coding cases. Results were consistent when only the 1327 emergency cases identified by “admission method” from coding were included, with more false positive cases with low case fatality (35 (14.7%)) being included for weekday versus weekend admissions (190 (19.5%) v 48 (13.7%), P<0.02). Among all acute stroke admissions in OXVASC, there was no imbalance in baseline stroke severity for weekends versus weekdays and no difference in case fatality at 30 days (adjusted odds ratio 0.85, 95% confidence interval 0.63 to 1.15; P=0.30) or any adverse “weekend effect” on modified Rankin score at 30 days (0.78, 0.61 to 0.99; P=0.04) or one year (0.76, 0.59 to 0.98; P=0.03) among incident strokes. Conclusion Retrospective studies of UK administrative hospital coding data to determine “weekend effects” on outcome in acute medical conditions, such as stroke, can be undermined by inaccurate coding, which can introduce biases that cannot be reliably dealt with by adjustment for case mix. PMID:27185754

Biases in detection of apparent "weekend effect" on outcome with administrative coding data: population based study of stroke.

PubMed

Li, Linxin; Rothwell, Peter M

2016-05-16

 To determine the accuracy of coding of admissions for stroke on weekdays versus weekends and any impact on apparent outcome.  Prospective population based stroke incidence study and a scoping review of previous studies of weekend effects in stroke.  Primary and secondary care of all individuals registered with nine general practices in Oxfordshire, United Kingdom (OXVASC, the Oxford Vascular Study).  All patients with clinically confirmed acute stroke in OXVASC identified with multiple overlapping methods of ascertainment in 2002-14 versus all acute stroke admissions identified by hospital diagnostic and mortality coding alone during the same period.  Accuracy of administrative coding data for all patients with confirmed stroke admitted to hospital in OXVASC. Difference between rates of "false positive" or "false negative" coding for weekday and weekend admissions. Impact of inaccurate coding on apparent case fatality at 30 days in weekday versus weekend admissions. Weekend effects on outcomes in patients with confirmed stroke admitted to hospital in OXVASC and impacts of other potential biases compared with those in the scoping review.  Among 92 728 study population, 2373 episodes of acute stroke were ascertained in OXVASC, of which 826 (34.8%) mainly minor events were managed without hospital admission, 60 (2.5%) occurred out of the area or abroad, and 195 (8.2%) occurred in hospital during an admission for a different reason. Of 1292 local hospital admissions for acute stroke, 973 (75.3%) were correctly identified by administrative coding. There was no bias in distribution of weekend versus weekday admission of the 319 strokes missed by coding. Of 1693 admissions for stroke identified by coding, 1055 (62.3%) were confirmed to be acute strokes after case adjudication. Among the 638 false positive coded cases, patients were more likely to be admitted on weekdays than at weekends (536 (41.0%) v 102 (26.5%); P<0.001), partly because of weekday elective admissions after previous stroke being miscoded as new stroke episodes (267 (49.8%) v 26 (25.5%); P<0.001). The 30 day case fatality after these elective admissions was lower than after confirmed acute stroke admissions (11 (3.8%) v 233 (22.1%); P<0.001). Consequently, relative 30 day case fatality for weekend versus weekday admissions differed (P<0.001) between correctly coded acute stroke admissions and false positive coding cases. Results were consistent when only the 1327 emergency cases identified by "admission method" from coding were included, with more false positive cases with low case fatality (35 (14.7%)) being included for weekday versus weekend admissions (190 (19.5%) v 48 (13.7%), P<0.02). Among all acute stroke admissions in OXVASC, there was no imbalance in baseline stroke severity for weekends versus weekdays and no difference in case fatality at 30 days (adjusted odds ratio 0.85, 95% confidence interval 0.63 to 1.15; P=0.30) or any adverse "weekend effect" on modified Rankin score at 30 days (0.78, 0.61 to 0.99; P=0.04) or one year (0.76, 0.59 to 0.98; P=0.03) among incident strokes.  Retrospective studies of UK administrative hospital coding data to determine "weekend effects" on outcome in acute medical conditions, such as stroke, can be undermined by inaccurate coding, which can introduce biases that cannot be reliably dealt with by adjustment for case mix. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Early Disseminated Lyme Disease Masquerading as Mononucleosis: A Case Report.

PubMed

Tumminello, Richard; Glaspey, Lindsey; Bhamidipati, Anita; Sheehan, Patrick; Patel, Sundip

2017-12-01

Disseminated Lyme disease can be difficult to diagnose, as it begins with nonspecific signs and symptoms, which, if not treated correctly, can lead to atrioventricular conduction blocks and meningitis. In addition, the diagnosis can be further complicated by potentially false-positive test results. We report a case of early-disseminated Lyme disease presenting with Borrelia meningitis and concomitant Lyme carditis, which was misdiagnosed as mononucleosis. A young, previously healthy patient had been hiking in the woods of upstate New York and 4 weeks later developed fever, night sweats, and myalgias. He was diagnosed with mononucleosis via a positive rapid heterophile agglutination antibody test to the Epstein-Barr virus at a walk-in clinic and was started on medications, but then subsequently developed left hip pain, a facial droop, and a very long first-degree atrioventricular conduction block. He went to the Emergency Department, where he had testing that confirmed disseminated Lyme disease. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: This case highlights the difficulty in early diagnosis of disseminated Lyme disease and how a potentially false-positive laboratory test can lead to the complications of Borrelia meningitis and Lyme carditis in untreated young healthy patients. Emergency physicians need to consider Lyme disease in patients with nonspecific signs and symptoms, especially if they have been outdoors for prolonged periods of time in Lyme-endemic areas. Copyright © 2017 Elsevier Inc. All rights reserved.

False Positivity of Non-Targeted Infections in Malaria Rapid Diagnostic Tests: The Case of Human African Trypanosomiasis

PubMed Central

Gillet, Philippe; Mumba Ngoyi, Dieudonné; Lukuka, Albert; Kande, Viktor; Atua, Benjamin; van Griensven, Johan; Muyembe, Jean-Jacques; Jacobs, Jan; Lejon, Veerle

2013-01-01

Background In endemic settings, diagnosis of malaria increasingly relies on the use of rapid diagnostic tests (RDTs). False positivity of such RDTs is poorly documented, although it is especially relevant in those infections that resemble malaria, such as human African trypanosomiasis (HAT). We therefore examined specificity of malaria RDT products among patients infected with Trypanosoma brucei gambiense. Methodology/Principal Findings Blood samples of 117 HAT patients and 117 matched non-HAT controls were prospectively collected in the Democratic Republic of the Congo. Reference malaria diagnosis was based on real-time PCR. Ten commonly used malaria RDT products were assessed including three two-band and seven three-band products, targeting HRP-2, Pf-pLDH and/or pan-pLDH antigens. Rheumatoid factor was determined in PCR negative subjects. Specificity of the 10 malaria RDT products varied between 79.5 and 100% in HAT-negative controls and between 11.3 and 98.8% in HAT patients. For seven RDT products, specificity was significantly lower in HAT patients compared to controls. False positive reactions in HAT were mainly observed for pan-pLDH test lines (specificities between 13.8 and 97.5%), but also occurred frequently for the HRP-2 test line (specificities between 67.9 and 98.8%). The Pf-pLDH test line was not affected by false-positive lines in HAT patients (specificities between 97.5 and 100%). False positivity was not associated to rheumatoid factor, detected in 7.6% of controls and 1.2% of HAT patients. Conclusions/Significance Specificity of some malaria RDT products in HAT was surprisingly low, and constitutes a risk for misdiagnosis of a fatal but treatable infection. Our results show the importance to assess RDT specificity in non-targeted infections when evaluating diagnostic tests. PMID:23638201

Predictive value of autoantibody testing for validating self-reported diagnoses of rheumatoid arthritis in the Women's Health Initiative.

PubMed

Walitt, Brian; Mackey, Rachel; Kuller, Lewis; Deane, Kevin D; Robinson, William; Holers, V Michael; Chang, Yue-Fang; Moreland, Larry

2013-05-01

Rheumatoid arthritis (RA) research using large databases is limited by insufficient case validity. Of 161,808 postmenopausal women in the Women's Health Initiative, 15,691 (10.2%) reported having RA, far higher than the expected 1% population prevalence. Since chart review for confirmation of an RA diagnosis is impractical in large cohort studies, the current study (2009-2011) tested the ability of baseline serum measurements of rheumatoid factor and anti-cyclic citrullinated peptide antibodies, second-generation assay (anti-CCP2), to identify physician-validated RA among the chart-review study participants with self-reported RA (n = 286). Anti-CCP2 positivity had the highest positive predictive value (PPV) (80.0%), and rheumatoid factor positivity the lowest (44.6%). Together, use of disease-modifying antirheumatic drugs and anti-CCP2 positivity increased PPV to 100% but excluded all seronegative cases (approximately 15% of all RA cases). Case definitions inclusive of seronegative cases had PPVs between 59.6% and 63.6%. False-negative results were minimized in these test definitions, as evidenced by negative predictive values of approximately 90%. Serological measurements, particularly measurement of anti-CCP2, improved the test characteristics of RA case definitions in the Women's Health Initiative.

Ultrasound-Guided Transcutaneous Needle Biopsy of the Base of the Tongue and Floor of the Mouth From a Submental Approach.

PubMed

Wagner, Jason M; Conrad, Rachel D; Cannon, Trinitia Y; Alleman, Anthony M

2016-05-01

Limited data exist regarding the feasibility of ultrasound-guided transcutaneous biopsy of the base of the tongue and floor of the mouth. This retrospective study reviewed 8 cases with lesions in the base of the tongue or floor of the mouth that were biopsied by fine-needle aspiration. Core biopsy was also needed in 1 case. All biopsies were technically successful, and all yielded squamous cell carcinoma. One biopsy yielded a false-positive result, as subsequent resection yielded high-grade dysplasia with no invasion. The other biopsy results were considered true-positive based on subsequent pathologic examinations (2 cases) or clinical/imaging follow-up (5 cases). There were no significant complications associated with the biopsies. © 2016 by the American Institute of Ultrasound in Medicine.

Prospective evaluation of radionuclide scanning in detection of intestinal necrosis in neonatal necrotizing enterocolitis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haase, G.M.; Sfakianakis, G.N.; Lobe, T.E.

1981-06-01

The ability of external imaging to demonstrate intestinal infarction in neonatal necrotizing enterocolitis (NEC) was prospectively evaluated. The radiopharmaceutical technetium--99m diphosphonate was injected intravenously and the patients subsequently underwent abdominal scanning. Clinical patient care and interpretation of the images were entirely independent throughout the study. Of 33 studies, 7 were positive, 4 were suspicious, and 22 were negative. One false positive study detected ischemia without transmural infarction. The second false positive scan occurred postoperatively and was due to misinterpretation of the hyperactivity along the surgical incision. None of the suspicious cases had damaged bowel. The two false negative studies clearlymore » failed to demonstrate frank intestinal necrosis. The presence of very small areas of infarction, errors in technical settings, subjective interpretation of scans and delayed clearance of the radionuclide in a critically ill neonate may all limit the accuracy of external abdominal scanning. However, in spite of an error rate of 12%, it is likely that this technique will enhance the present clinical, laboratory, and radiologic parameters of patient management in NEC.« less

Tests for a disease-susceptibility locus allowing for an inbreeding coefficient (F).

PubMed

Song, Kijoung; Elston, Robert C

2003-11-01

We begin by discussing the false positive test results that arise because of cryptic relatedness and population substructure when testing a disease susceptibility locus. We extend and evaluate the Hardy-Weinberg disequilibrium (HWD) method, allowing for an inbreeding coefficient (F) in a similar way that Devlin and Roeder (1999) allowed for inbreeding in a case-control study. Then we compare the HWD measure and the common direct measure of linkage disequilibrium, both when there is no population substructure (F = 0) and when there is population substructure (F not = 0), for a single marker. The HWD test statistic gives rise to false positives caused by population stratification. These false positives can be controlled by adjusting the test statistic for the amount of variance inflation caused by the inbreeding coefficient (F). The power loss for the HWD test that arises when controlling for population structure is much less than that which arises for the common direct measure of linkage disequilibrium. However, in the multiplicative model, the HWD test has virtually no power even when allowing for non-zero F.

Critical Congenital Heart Disease Screening by Pulse Oximetry in a Neonatal Intensive Care Unit

PubMed Central

Manja, Veena; Mathew, Bobby; Carrion, Vivien; Lakshminrusimha, Satyan

2014-01-01

Critical congenital heart disease (CCHD) screening is effective in asymptomatic late preterm and term newborn infants with a low false positive rate (0.035%). Objective (1) To compare 2817 NICU discharges before and after implementation of CCHD screening; and (2) to evaluate CCHD screening at < 35 weeks gestation. Methods collection of results of CCHD screening including preductal and postductal SpO2 values. Results During the pre-CCHD screen period, 1247 infants were discharged from the NICU and one case of CCHD was missed. After 3/1/12, 1508 CCHD screens were performed among 1570 discharges and no CCHDs were missed. The preductal and postductal SpO2 values were 98.8±1.4% and 99±1.3% respectively in preterm and 98.9±1.3% and 98.9±1.4% in term infants. Ten infants had false positive screens (10/1508=0.66%). Conclusions Performing universal screening in the NICU is feasible but is associated with a higher false positive rate compared to asymptomatic newborn infants. PMID:25058746

Hilbertian sine as an absolute measure of Bayesian inference in ISR, homeland security, medicine, and defense

NASA Astrophysics Data System (ADS)

Jannson, Tomasz; Wang, Wenjian; Hodelin, Juan; Forrester, Thomas; Romanov, Volodymyr; Kostrzewski, Andrew

2016-05-01

In this paper, Bayesian Binary Sensing (BBS) is discussed as an effective tool for Bayesian Inference (BI) evaluation in interdisciplinary areas such as ISR (and, C3I), Homeland Security, QC, medicine, defense, and many others. In particular, Hilbertian Sine (HS) as an absolute measure of BI, is introduced, while avoiding relativity of decision threshold identification, as in the case of traditional measures of BI, related to false positives and false negatives.

Automated Detection, Localization, and Classification of Traumatic Vertebral Body Fractures in the Thoracic and Lumbar Spine at CT

PubMed Central

Burns, Joseph E.; Yao, Jianhua; Muñoz, Hector

2016-01-01

Purpose To design and validate a fully automated computer system for the detection and anatomic localization of traumatic thoracic and lumbar vertebral body fractures at computed tomography (CT). Materials and Methods This retrospective study was HIPAA compliant. Institutional review board approval was obtained, and informed consent was waived. CT examinations in 104 patients (mean age, 34.4 years; range, 14–88 years; 32 women, 72 men), consisting of 94 examinations with positive findings for fractures (59 with vertebral body fractures) and 10 control examinations (without vertebral fractures), were performed. There were 141 thoracic and lumbar vertebral body fractures in the case set. The locations of fractures were marked and classified by a radiologist according to Denis column involvement. The CT data set was divided into training and testing subsets (37 and 67 subsets, respectively) for analysis by means of prototype software for fully automated spinal segmentation and fracture detection. Free-response receiver operating characteristic analysis was performed. Results Training set sensitivity for detection and localization of fractures within each vertebra was 0.82 (28 of 34 findings; 95% confidence interval [CI]: 0.68, 0.90), with a false-positive rate of 2.5 findings per patient. The sensitivity for fracture localization to the correct vertebra was 0.88 (23 of 26 findings; 95% CI: 0.72, 0.96), with a false-positive rate of 1.3. Testing set sensitivity for the detection and localization of fractures within each vertebra was 0.81 (87 of 107 findings; 95% CI: 0.75, 0.87), with a false-positive rate of 2.7. The sensitivity for fracture localization to the correct vertebra was 0.92 (55 of 60 findings; 95% CI: 0.79, 0.94), with a false-positive rate of 1.6. The most common cause of false-positive findings was nutrient foramina (106 of 272 findings [39%]). Conclusion The fully automated computer system detects and anatomically localizes vertebral body fractures in the thoracic and lumbar spine on CT images with a high sensitivity and a low false-positive rate. © RSNA, 2015 Online supplemental material is available for this article. PMID:26172532

Validation of sentinel lymph node biopsy in breast cancer women N1-N2 with complete axillary response after neoadjuvant chemotherapy. Multicentre study in Tarragona.

PubMed

Carrera, D; de la Flor, M; Galera, J; Amillano, K; Gomez, M; Izquierdo, V; Aguilar, E; López, S; Martínez, M; Martínez, S; Serra, J M; Pérez, M; Martin, L

2016-01-01

The aim of our study was to evaluate sentinel lymph node biopsy as a diagnostic test for assessing the presence of residual metastatic axillary lymph nodes after neoadjuvant chemotherapy, replacing the need for a lymphadenectomy in negative selective lymph node biopsy patients. A multicentre, diagnostic validation study was conducted in the province of Tarragona, on women with T1-T3, N1-N2 breast cancer, who presented with a complete axillary response after neoadjuvant chemotherapy. Study procedures consisted of performing an selective lymph node biopsy followed by lymphadenectomy. A total of 53 women were included in the study. Surgical detection rate was 90.5% (no sentinel node found in 5 patients). Histopathological analysis of the lymphadenectomy showed complete disease regression of axillary nodes in 35.4% (17/48) of the patients, and residual axillary node involvement in 64.6% (31/48) of them. In lymphadenectomy positive patients, 28 had a positive selective lymph node biopsy (true positive), while 3 had a negative selective lymph node biopsy (false negative). Of the 28 true selective lymph node biopsy positives, the sentinel node was the only positive node in 10 cases. All lymphadenectomy negative cases were selective lymph node biopsy negative. These data yield a sensitivity of 93.5%, a false negative rate of 9.7%, and a global test efficiency of 93.7%. Selective lymph node biopsy after chemotherapy in patients with a complete axillary response provides valid and reliable information regarding axillary status after neoadjuvant treatment, and might prevent lymphadenectomy in cases with negative selective lymph node biopsy. Copyright © 2016 Elsevier España, S.L.U. and SEMNIM. All rights reserved.

Differential specificity of selective culture media for enumeration of pathogenic vibrios: advantages and limitations of multi-plating methods.

PubMed

Nigro, Olivia D; Steward, Grieg F

2015-04-01

Plating environmental samples on vibrio-selective chromogenic media is a commonly used technique that allows one to quickly estimate concentrations of putative vibrio pathogens or to isolate them for further study. Although this approach is convenient, its usefulness depends directly on how well the procedure selects against false positives. We tested whether a chromogenic medium, CHROMagar Vibrio (CaV), used alone (single-plating) or in combination (double-plating) with a traditional medium thiosulfate-citrate-bile-salts (TCBS), could improve the discrimination among three pathogenic vibrio species (Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus) and thereby decrease the number of false-positive colonies that must be screened by molecular methods. Assays were conducted on water samples from two estuarine environments (one subtropical, one tropical) in a variety of seasonal conditions. The results of the double-plating method were confirmed by PCR and 16S rRNA sequencing. Our data indicate that there is no significant difference in the false-positive rate between CaV and TCBS when using a single-plating technique, but determining color changes on the two media sequentially (double-plating) reduced the rate of false positive identification in most cases. The improvement achieved was about two-fold on average, but varied greatly (from 0- to 5-fold) and depended on the sampling time and location. The double-plating method was most effective for V. vulnificus in warm months, when overall V. vulnificus abundance is high (false positive rates as low as 2%, n=178). Similar results were obtained for V. cholerae (minimum false positive rate of 16%, n=146). In contrast, the false positive rate for V. parahaemolyticus was always high (minimum of 59%, n=109). Sequence analysis of false-positive isolates indicated that the majority of confounding isolates are from the Vibrionaceae family, however, members of distantly related bacterial groups were also able to grow on vibrio-selective media, even when using the double-plating method. In conclusion, the double-plating assay is a simple means to increase the efficiency of identifying pathogenic vibrios in aquatic environments and to reduce the number of molecular assays required for identity confirmation. However, the high spatial and temporal variability in the performance of the media mean that molecular approaches are still essential to obtain the most accurate vibrio abundance estimates from environmental samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Intraoperative monitoring of somatosensory (SSEPs) and transcranial electric motor-evoked potentials (tce-MEPs) during surgical correction of neuromuscular scoliosis in patients with central or peripheral nervous system diseases.

PubMed

Pastorelli, F; Di Silvestre, M; Vommaro, F; Maredi, E; Morigi, A; Bacchin, M R; Bonarelli, S; Plasmati, R; Michelucci, R; Greggi, T

2015-11-01

Combined intraoperative monitoring (IOM) of transcranial electric motor-evoked potentials (tce-MEPs) and somatosensory-evoked potentials (SSEPs) is safe and effective for spinal cord monitoring during scoliosis surgery. However, the literature data regarding the reliability of spinal cord monitoring in patients with neuromuscular scoliosis are conflicting and need to be confirmed. We reviewed IOM records of 40 consecutive patients with neuromuscular scoliosis related to central nervous system (CNS) (29 pts) or peripheral nervous system (PNS) (11 patients) diseases, who underwent posterior fusion with instrumentation surgery for spinal deformity. Multimodalitary IOM with SSEPs and tce-MEPs was performed. Spinal cord monitoring using at least one modality was attempted in 38/40 (95 %) patients. No false-negative results were present in either group, but a relatively high incidence of false-positive cases (4/29, 13.8 %) was noted in the CNS group. Two patients in the CNS group and one patient in the PNS group presented transient postoperative motor deficits (true positive), related to surgical manoeuvres in two cases and to malposition in the other one. Multimodalitary IOM is safe and effective to detect impending spinal cord and peripheral nerves dysfunction in neuromuscular scoliosis surgery. However, the interpretation of neurophysiological data may be challenging in such patients, and the rate of false-positive results is high when pre-operatory motor deficits are severe.

Rating the "Raters": Legal Exposure of Trustmark Authorities in the Context of Consumer Health Informatics

PubMed Central

Terry, Nicolas P

2000-01-01

There are three areas of potential legal exposure for an organization such as a trustmark authority involved in ehealth quality rating. First, an ehealth provider may make a complaint about negative or impliedly negative ratings rendered by the ratings body (false negative). Typically, a negative ratings complaint would rely on defamation or product disparagement causes of action. In some cases such complaints could be defended on the basis of absence of malice (US). Second, the rating body might render a positive rating on ehealth data that a third party allegedly relied upon and suffered injury (false positive). While the primary cause of action would be against the ehealth data provider, questions may arise as to possible liability of the trustmark authority. For example, some US liability exposure is possible based on cases involving the potential liability of product warrantors, trade associations and certifiers or endorsers. Third, a ratings body may face public law liability for its own web misfeasance. Several risk management approaches are possible and would not necessarily be mutually exclusive. These approaches will require careful investigation to assess their risk reduction potential and, in some cases, legislation.

Rating the Raters: Legal Exposure of Trustmark Authorities in the Context of Consumer Health Informatics

PubMed Central

2000-01-01

There are three areas of potential legal exposure for an organization such as a trustmark authority involved in e-health quality rating. First, an e-health provider may make a complaint about negative or impliedly negative ratings rendered by the ratings body (false negative). Typically, a negative ratings complaint would rely on defamation or product disparagement causes of action. In some cases such complaints could be defended on the basis of absence of malice (US). Second, the rating body might render a positive rating on e-health data that a third party allegedly relied upon and suffered injury (false positive). While the primary cause of action would be against the e-health data provider, questions may arise as to the possible liability of the trustmark authority. For example, some US liability exposure is possible based on cases involving the potential liability of product warrantors, trade associations, and certifiers or endorsers. Third, a ratings body may face public law liability for its own web misfeasance. Several risk management approaches are possible and would not necessarily be mutually exclusive. These approaches will require careful investigation to assess their risk reduction potential and, in some cases, the introduction of legislation. PMID:11720941

Rating the raters: legal exposure of trustmark authorities in the context of consumer health informatics.

PubMed

Terry, N P

2000-01-01

There are three areas of potential legal exposure for an organization such as a trustmark authority involved in e-health quality rating. First, an e-health provider may make a complaint about negative or impliedly negative ratings rendered by the ratings body (false negative). Typically, a negative ratings complaint would rely on defamation or product disparagement causes of action. In some cases such complaints could be defended on the basis of absence of malice (US). Second, the rating body might render a positive rating on e-health data that a third party allegedly relied upon and suffered injury (false positive). While the primary cause of action would be against the e-health data provider, questions may arise as to the possible liability of the trustmark authority. For example, some US liability exposure is possible based on cases involving the potential liability of product warrantors, trade associations, and certifiers or endorsers. Third, a ratings body may face public law liability for its own web misfeasance. Several risk management approaches are possible and would not necessarily be mutually exclusive. These approaches will require careful investigation to assess their risk reduction potential and, in some cases, the introduction of legislation.

Detection of occult, undisplaced hip fractures with a dual-energy CT algorithm targeted to detection of bone marrow edema.

PubMed

Reddy, T; McLaughlin, P D; Mallinson, P I; Reagan, A C; Munk, P L; Nicolaou, S; Ouellette, H A

2015-02-01

The purpose of this study is to describe our initial clinical experience with dual-energy computed tomography (DECT) virtual non-calcium (VNC) images for the detection of bone marrow (BM) edema in patients with suspected hip fracture following trauma. Twenty-five patients presented to the emergency department at a level 1 trauma center between January 1, 2011 and January 1, 2013 with clinical suspicion of hip fracture and normal radiographs were included. All CT scans were performed on a dual-source, dual-energy CT system. VNC images were generated using prototype software and were compared to regular bone reconstructions by two musculoskeletal radiologists in consensus. Radiological and/or clinical diagnosis of fracture at 30-day follow-up was used as the reference standard. Twenty-one patients were found to have DECT-VNC signs of bone marrow edema. Eighteen of these 21 patients were true positive and three were false positive. A concordant fracture was clearly seen on bone reconstruction images in 15 of the 18 true positive cases. In three cases, DECT-VNC was positive for bone marrow edema where bone reconstruction CT images were negative. Four patients demonstrated no DECT-VNC signs of bone marrow edema: two cases were true negative, two cases were false negative. When compared with the gold standard of hip fracture determined at retrospective follow-up, the sensitivity of DECT-VNC images of the hip was 90 %, specificity was 40 %, positive predictive value was 86 %, and negative predictive value was 50 %. Our initial experience would suggest that DECT-VNC is highly sensitive but poorly specific in the diagnosis of hip fractures in patients with normal radiographs. The value of DECT-VNC primarily lies in its ability to help detect fractures which may be subtle or undetectable on bone reconstruction CT images.

Comparison of technetium-99m-HM-PAO leukocytes with indium-111-oxine leukocytes for localizing intraabdominal sepsis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mountford, P.J.; Kettle, A.G.; O'Doherty, M.J.

Technetium-99m-HM-PAO (({sup 99m}Tc)HM-PAO) leukocyte and indium-111-oxine (111In-oxine) leukocyte scanning were carried out simultaneously in 41 patients at 4 hr and 24 hr after reinjection to determine whether the 4-hr {sup 99m}Tc scan could replace the 24-hr {sup 111}In scan for detecting intraabdominal sepsis. Abdominal infection was confirmed in 12 cases. The 4-hr {sup 99}Tc-leukocyte scan, the 4-hr {sup 111}In-leukocyte scan, and the 24-hr {sup 111}In-leukocyte scan yielded a sensitivity of 100%, 67%, and 100%, respectively, and a specificity of 62%, 90%, and 86%, respectively. The 24-hr {sup 99m}Tc-leukocyte scan also produced a sensitivity of 100%, but it was falsely positivemore » in all 29 cases without infection due to physiologic bowel uptake. False-positive 4-hr {sup 99m}Tc-leukocyte scans were also produced by physiologic bowel uptake in seven cases all of whom had true-negative 4-hr and 24-hr {sup 111}In-leukocyte scans. Because of the high incidence of false-positive 4-hr ({sup 99m}Tc)HM-PAO leukocyte scans, it was concluded that they could not replace 24-hr {sup 111}In-leukocyte scans for detecting intraabdominal sepsis, and that serial {sup 99m}Tc leukocyte scans starting earlier than 4 hr after reinjection must be evaluated.« less

Influencing clinicians and healthcare managers: can ROC be more persuasive?

NASA Astrophysics Data System (ADS)

Taylor-Phillips, S.; Wallis, M. G.; Duncan, A.; Gale, A. G.

2010-02-01

Receiver Operating Characteristic analysis provides a reliable and cost effective performance measurement tool, without using full clinical trials. However, when ROC analysis shows that performance is statistically superior in one condition than another it is difficult to relate this result to effects in practice, or even to determine whether it is clinically significant. In this paper we present two concurrent analyses: using ROC methods alongside single threshold recall rate data, and suggest that reporting both provides complimentary data. Four mammographers read 160 difficult cases (41% malignant) twice, with and without prior mammograms. Lesion location and probability of malignancy was reported for each case and analyzed using JAFROC. Concurrently each participant chose recall or return to screen for each case. JAFROC analysis showed that the presence of prior mammograms improved performance (p<.05). Single threshold data showed a trend towards a 26% increase in the number of false positive recalls without prior mammograms (p=.056). If this trend were present throughout the NHS Breast Screening Programme then discarding prior mammograms would correspond to an increase in recall rate from 4.6% to 5.3%, and 12,414 extra women recalled annually for assessment. Whilst ROC methods account for all possible thresholds of recall and have higher power, providing a single threshold example of false positive, false negative, and recall rates when reporting results could be more influential for clinicians. This paper discusses whether this is a useful additional method of presenting data, or whether it is misleading and inaccurate.

The reproducibility of research and the misinterpretation of p-values

PubMed Central

2017-01-01

We wish to answer this question: If you observe a ‘significant’ p-value after doing a single unbiased experiment, what is the probability that your result is a false positive? The weak evidence provided by p-values between 0.01 and 0.05 is explored by exact calculations of false positive risks. When you observe p = 0.05, the odds in favour of there being a real effect (given by the likelihood ratio) are about 3 : 1. This is far weaker evidence than the odds of 19 to 1 that might, wrongly, be inferred from the p-value. And if you want to limit the false positive risk to 5%, you would have to assume that you were 87% sure that there was a real effect before the experiment was done. If you observe p = 0.001 in a well-powered experiment, it gives a likelihood ratio of almost 100 : 1 odds on there being a real effect. That would usually be regarded as conclusive. But the false positive risk would still be 8% if the prior probability of a real effect were only 0.1. And, in this case, if you wanted to achieve a false positive risk of 5% you would need to observe p = 0.00045. It is recommended that the terms ‘significant’ and ‘non-significant’ should never be used. Rather, p-values should be supplemented by specifying the prior probability that would be needed to produce a specified (e.g. 5%) false positive risk. It may also be helpful to specify the minimum false positive risk associated with the observed p-value. Despite decades of warnings, many areas of science still insist on labelling a result of p < 0.05 as ‘statistically significant’. This practice must contribute to the lack of reproducibility in some areas of science. This is before you get to the many other well-known problems, like multiple comparisons, lack of randomization and p-hacking. Precise inductive inference is impossible and replication is the only way to be sure. Science is endangered by statistical misunderstanding, and by senior people who impose perverse incentives on scientists. PMID:29308247

A new CAD approach for improving efficacy of cancer screening

NASA Astrophysics Data System (ADS)

Zheng, Bin; Qian, Wei; Li, Lihua; Pu, Jiantao; Kang, Yan; Lure, Fleming; Tan, Maxine; Qiu, Yuchen

2015-03-01

Since performance and clinical utility of current computer-aided detection (CAD) schemes of detecting and classifying soft tissue lesions (e.g., breast masses and lung nodules) is not satisfactory, many researchers in CAD field call for new CAD research ideas and approaches. The purpose of presenting this opinion paper is to share our vision and stimulate more discussions of how to overcome or compensate the limitation of current lesion-detection based CAD schemes in the CAD research community. Since based on our observation that analyzing global image information plays an important role in radiologists' decision making, we hypothesized that using the targeted quantitative image features computed from global images could also provide highly discriminatory power, which are supplementary to the lesion-based information. To test our hypothesis, we recently performed a number of independent studies. Based on our published preliminary study results, we demonstrated that global mammographic image features and background parenchymal enhancement of breast MR images carried useful information to (1) predict near-term breast cancer risk based on negative screening mammograms, (2) distinguish between true- and false-positive recalls in mammography screening examinations, and (3) classify between malignant and benign breast MR examinations. The global case-based CAD scheme only warns a risk level of the cases without cueing a large number of false-positive lesions. It can also be applied to guide lesion-based CAD cueing to reduce false-positives but enhance clinically relevant true-positive cueing. However, before such a new CAD approach is clinically acceptable, more work is needed to optimize not only the scheme performance but also how to integrate with lesion-based CAD schemes in the clinical practice.

Applying a new computer-aided detection scheme generated imaging marker to predict short-term breast cancer risk

NASA Astrophysics Data System (ADS)

Mirniaharikandehei, Seyedehnafiseh; Hollingsworth, Alan B.; Patel, Bhavika; Heidari, Morteza; Liu, Hong; Zheng, Bin

2018-05-01

This study aims to investigate the feasibility of identifying a new quantitative imaging marker based on false-positives generated by a computer-aided detection (CAD) scheme to help predict short-term breast cancer risk. An image dataset including four view mammograms acquired from 1044 women was retrospectively assembled. All mammograms were originally interpreted as negative by radiologists. In the next subsequent mammography screening, 402 women were diagnosed with breast cancer and 642 remained negative. An existing CAD scheme was applied ‘as is’ to process each image. From CAD-generated results, four detection features including the total number of (1) initial detection seeds and (2) the final detected false-positive regions, (3) average and (4) sum of detection scores, were computed from each image. Then, by combining the features computed from two bilateral images of left and right breasts from either craniocaudal or mediolateral oblique view, two logistic regression models were trained and tested using a leave-one-case-out cross-validation method to predict the likelihood of each testing case being positive in the next subsequent screening. The new prediction model yielded the maximum prediction accuracy with an area under a ROC curve of AUC  =  0.65  ±  0.017 and the maximum adjusted odds ratio of 4.49 with a 95% confidence interval of (2.95, 6.83). The results also showed an increasing trend in the adjusted odds ratio and risk prediction scores (p  <  0.01). Thus, this study demonstrated that CAD-generated false-positives might include valuable information, which needs to be further explored for identifying and/or developing more effective imaging markers for predicting short-term breast cancer risk.

Effect of postmortem sampling technique on the clinical significance of autopsy blood cultures.

PubMed

Hove, M; Pencil, S D

1998-02-01

Our objective was to investigate the value of postmortem autopsy blood cultures performed with an iodine-subclavian technique relative to the classical method of atrial heat searing and antemortem blood cultures. The study consisted of a prospective autopsy series with each case serving as its own control relative to subsequent testing, and a retrospective survey of patients coming to autopsy who had both autopsy blood cultures and premortem blood cultures. A busy academic autopsy service (600 cases per year) at University of Texas Medical Branch Hospitals, Galveston, Texas, served as the setting for this work. The incidence of non-clinically relevant (false-positive) culture results were compared using different methods for collecting blood samples in a prospective series of 38 adult autopsy specimens. One hundred eleven adult autopsy specimens in which both postmortem and antemortem blood cultures were obtained were studied retrospectively. For both studies, positive culture results were scored as either clinically relevant or false positives based on analysis of the autopsy findings and the clinical summary. The rate of false-positive culture results obtained by an iodine-subclavian technique from blood drawn soon after death were statistically significantly lower (13%) than using the classical method of obtaining blood through the atrium after heat searing at the time of the autopsy (34%) in the same set of autopsy subjects. When autopsy results were compared with subjects' antemortem blood culture results, there was no significant difference in the rate of non-clinically relevant culture results in a paired retrospective series of antemortem blood cultures and postmortem blood cultures using the iodine-subclavian postmortem method (11.7% v 13.5%). The results indicate that autopsy blood cultures obtained using the iodine-subclavian technique have reliability equivalent to that of antemortem blood cultures.

Public health consequences of a false-positive laboratory test result for Brucella--Florida, Georgia, and Michigan, 2005.

PubMed

2008-06-06

Human brucellosis, a nationally notifiable disease, is uncommon in the United States. Most human cases have occurred in returned travelers or immigrants from regions where brucellosis is endemic, or were acquired domestically from eating illegally imported, unpasteurized fresh cheeses. In January 2005, a woman aged 35 years who lived in Nassau County, Florida, received a diagnosis of brucellosis, based on results of a Brucella immunoglobulin M (IgM) enzyme immunoassay (EIA) performed in a commercial laboratory using analyte specific reagents (ASRs); this diagnosis prompted an investigation of dairy products in two other states. Subsequent confirmatory antibody testing by Brucella microagglutination test (BMAT) performed at CDC on the patient's serum was negative. The case did not meet the CDC/Council of State and Territorial Epidemiologists' (CSTE) definition for a probable or confirmed brucellosis case, and the initial EIA result was determined to be a false positive. This report summarizes the case history, laboratory findings, and public health investigations. CDC recommends that Brucella serology testing only be performed using tests cleared or approved by the Food and Drug Administration (FDA) or validated under the Clinical Laboratory Improvement Amendments (CLIA) and shown to reliably detect the presence of Brucella infection. Results from these tests should be considered supportive evidence for recent infection only and interpreted in the context of a clinically compatible illness and exposure history. EIA is not considered a confirmatory Brucella antibody test; positive screening test results should be confirmed by Brucella-specific agglutination (i.e., BMAT or standard tube agglutination test) methods.

Evaluation of the on-site immunoassay drug-screening device Triage-TOX in routine forensic autopsy.

PubMed

Tominaga, Mariko; Michiue, Tomomi; Maeda, Hitoshi

2015-11-01

Instrumental identification of drugs with quantification is essential in forensic toxicology, while on-site immunoassay urinalysis drug-screening devices conveniently provide preliminary information when adequately used. However, suitable or sufficient urine specimens are not always available. The present study evaluated the efficacy of a new on-site immunoassay drug-screening device Triage-TOX (Alere Inc., San Diego, CA, USA), which has recently been developed to provide objective data on the one-step automated processor, using 51 urine and 19 pericardial fluid samples from 66 forensic autopsy cases, compared with Triage-Drug of Abuse (DOA) and Monitect-9. For benzodiazepines, the positive predictive value and specificity of Triage-TOX were higher than those of Triage-DOA; however, sensitivity was higher with Monitect-9, despite frequent false-positives. The results for the other drugs with the three devices also included a few false-negatives and false-positives. These observations indicate the applicability of Triage-TOX in preliminary drug screening using urine or alternative materials in routine forensic autopsy, when a possible false-negative is considered, especially for benzodiazepines, providing objective information; however, the combined use of another device such as Monitect-9 can help minimize misinterpretation prior to instrumental analysis. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Psychology's Renaissance.

PubMed

Nelson, Leif D; Simmons, Joseph; Simonsohn, Uri

2018-01-04

In 2010-2012, a few largely coincidental events led experimental psychologists to realize that their approach to collecting, analyzing, and reporting data made it too easy to publish false-positive findings. This sparked a period of methodological reflection that we review here and call Psychology's Renaissance. We begin by describing how psychologists' concerns with publication bias shifted from worrying about file-drawered studies to worrying about p-hacked analyses. We then review the methodological changes that psychologists have proposed and, in some cases, embraced. In describing how the renaissance has unfolded, we attempt to describe different points of view fairly but not neutrally, so as to identify the most promising paths forward. In so doing, we champion disclosure and preregistration, express skepticism about most statistical solutions to publication bias, take positions on the analysis and interpretation of replication failures, and contend that meta-analytical thinking increases the prevalence of false positives. Our general thesis is that the scientific practices of experimental psychologists have improved dramatically.

Coinfection of hepatitis A virus genotype IA and IIIA complicated with autoimmune hemolytic anemia, prolonged cholestasis, and false-positive immunoglobulin M anti-hepatitis E virus: a case report.

PubMed

Kim, Hee Sup; Jeong, Sook Hyang; Jang, Je Hyuck; Myung, Hyung Joon; Kim, Jin Wook; Bang, Soo Mee; Song, Sang Hoon; Kim, Haeryoung; Yun, Hae Sun

2011-12-01

A 37-year-old male presented with fever and jaundice was diagnosed as hepatitis A complicated with progressive cholestasis and severe autoimmune hemolytic anemia. He was treated with high-dose prednisolone (1.5 mg/kg), and eventually recovered. His initial serum contained genotype IA hepatitis A virus (HAV), which was subsequently replaced by genotype IIIA HAV. Moreover, at the time of development of hemolytic anemia, he became positive for immunoglobulin M (IgM) anti-hepatitis E virus (HEV). We detected HAV antigens in the liver biopsy specimen, while we detected neither HEV antigen in the liver nor HEV RNA in his serum. This is the first report of hepatitis A coinfected with two different genotypes manifesting with autoimmune hemolytic anemia, prolonged cholestasis, and false-positive IgM anti-HEV.

Coinfection of hepatitis A virus genotype IA and IIIA complicated with autoimmune hemolytic anemia, prolonged cholestasis, and false-positive immunoglobulin M anti-hepatitis E virus: a case report

PubMed Central

Kim, Hee-Sup; Jang, Je-Hyuck; Myung, Hyung-Joon; Kim, Jin-Wook; Bang, Soo-Mee; Song, Sang Hoon; Kim, Haeryoung; Yun, Hae Sun

2011-01-01

A 37-year-old male presented with fever and jaundice was diagnosed as hepatitis A complicated with progressive cholestasis and severe autoimmune hemolytic anemia. He was treated with high-dose prednisolone (1.5 mg/kg), and eventually recovered. His initial serum contained genotype IA hepatitis A virus (HAV), which was subsequently replaced by genotype IIIA HAV. Moreover, at the time of development of hemolytic anemia, he became positive for immunoglobulin M (IgM) anti-hepatitis E virus (HEV). We detected HAV antigens in the liver biopsy specimen, while we detected neither HEV antigen in the liver nor HEV RNA in his serum. This is the first report of hepatitis A coinfected with two different genotypes manifesting with autoimmune hemolytic anemia, prolonged cholestasis, and false-positive IgM anti-HEV. PMID:22310798

[Differential diagnosis of Dandy-Walker syndrome different presentations].

PubMed

Tobías-González, Pablo; Gil Mira, Mar; Valero de Bernabé, Javier; Zapardiel, Ignacio

2012-08-01

Dandy-Walker syndrome is a set of abnormalities of the posterior fossa including three modalities: classic Dandy-Walker malformation, Dandy-Walker variant and mega-cisterna magna. Our objective is clarify the differential diagnosis among these entities. Descriptive and retrospective study of Dandy-Walker cases diagnosed at our Department during the last five years plus a review of the related Medical literature. Three cases of Dandy-Walker modalities are reported: one case of classic Dandy-Walker malformation, one case of Dandy-Walker variant, and one case of false Dandy-Walker. In the first two cases the patients underwent legal abortion, whereas in the last one a healthy male newborn was delivered in the week 38 of gestation. Malformations in the posterior fossa, including Dandy-Walker syndrome, are still a challenge in prenatal diagnosis. Technical developments in imaging, such as in three-dimensional sonography and magnetic resonance, allow higher resolution and multiplanar images for an easier diagnose. There is a high rate of false positive, particularly before the 18th week of gestation. It is advisable not to establish a final diagnose before that week.

Probabilistic Tractography of the Cranial Nerves in Vestibular Schwannoma.

PubMed

Zolal, Amir; Juratli, Tareq A; Podlesek, Dino; Rieger, Bernhard; Kitzler, Hagen H; Linn, Jennifer; Schackert, Gabriele; Sobottka, Stephan B

2017-11-01

Multiple recent studies have reported on diffusion tensor-based fiber tracking of cranial nerves in vestibular schwannoma, with conflicting results as to the accuracy of the method and the occurrence of cochlear nerve depiction. Probabilistic nontensor-based tractography might offer advantages in terms of better extraction of directional information from the underlying data in cranial nerves, which are of subvoxel size. Twenty-one patients with large vestibular schwannomas were recruited. The probabilistic tracking was run preoperatively and the position of the potential depictions of the facial and cochlear nerves was estimated postoperatively by 3 independent observers in a blinded fashion. The true position of the nerve was determined intraoperatively by the surgeon. Thereafter, the imaging-based estimated position was compared with the intraoperatively determined position. Tumor size, cystic appearance, and postoperative House-Brackmann score were analyzed with regard to the accuracy of the depiction of the nerves. The probabilistic tracking showed a connection that correlated to the position of the facial nerve in 81% of the cases and to the position of the cochlear nerve in 33% of the cases. Altogether, the resulting depiction did not correspond to the intraoperative position of any of the nerves in 3 cases. In a majority of cases, the position of the facial nerve, but not of the cochlear nerve, could be estimated by evaluation of the probabilistic tracking results. However, false depictions not corresponding to any nerve do occur and cannot be discerned as such from the image only. Copyright © 2017 Elsevier Inc. All rights reserved.

The clinical impact of a false-positive urine cocaine screening result on a patient's pain management.

PubMed

Kim, James A; Ptolemy, Adam S; Melanson, Stacy E F; Janfaza, David R; Ross, Edgar L

2015-06-01

The urine of a patient admitted for chest and epigastric pain tested positive for cocaine using an immunoassay-based drug screening method (positive/negative cutoff concentration 150 ng/mL). Despite the patient's denial of recent cocaine use, this positive cocaine screening result in conjunction with a remote history of drug misuse impacted the patient's recommended pain therapy. Specifically, these factors prompted the clinical team to question the appropriateness of opioids and other potentially addictive therapeutics during the treatment of cancer pain from previously undetected advanced pancreatic carcinoma. After pain management and clinical pathology consultation, it was decided that the positive cocaine screening result should be confirmed by gas chromatography-mass spectrometry (GC-MS) testing. This more sensitive and specific analytical technique revealed that both cocaine and its primary metabolite benzoylecgonine were undetectable (i.e., less than the assay detection limit of 50 ng/mL), thus indicating that the positive urine screening result was falsely positive. With this confirmation, the pain management service team was reassured in offering intrathecal pump (ITP) therapy for pain control. ITP implantation was well tolerated, and the patient eventually achieved excellent pain relief. However, ITP therapy most likely would not have been utilized without the GC-MS confirmation testing unless alternative options failed and extensive vigilant monitoring was initiated. As exemplified in this case, confirmatory drug testing should be performed on specimens with unexpected immunoassay-based drug screening results. To our knowledge, this is the first report of a false-positive urine cocaine screening result and its impact on patient management. Wiley Periodicals, Inc.

Rubella Surveillance and Diagnostic Testing among a Low-Prevalence Population, New York City, 2012-2013.

PubMed

Isaac, Beth M; Zucker, Jane R; Giancotti, Francesca R; Abernathy, Emily; Icenogle, Joseph; Rakeman, Jennifer L; Rosen, Jennifer B

2017-09-01

The New York City Department of Health and Mental Hygiene (DOHMH) receives clinical and laboratory reports for rubella. Because rubella immunoglobulin M (IgM) assays may produce false-positive results and rubella infections may be asymptomatic, interpretation of positive IgM results can be challenging. Rubella reports received by DOHMH in 2012 to 2013 were reviewed. The rubella IgM testing purpose was determined through case investigation. Results of IgM testing by indirect enzyme-linked immunosorbent assay (ELISA) and capture enzyme immunoassay (EIA) were compared to determine positive predictive value (PPV) and specificity. DOHMH received 199 rubella reports; 2 were true cases. Of all reports, 77.9% were tested for rubella IgM erroneously, 19.6% were tested for diagnostic purposes, 2.0% had unknown test purpose, and 0.5% were not tested. PPV of indirect ELISA was 6% overall, 14% for diagnostic tests, and 0% for tests ordered erroneously. PPV of capture EIA was 29% overall, 50% for diagnostic tests, and 0% for tests ordered erroneously. Overall, specificity was 52% for indirect ELISA and 85% for capture EIA. Limiting rubella IgM testing to patients for whom rubella diagnosis is suspected and using a more specific IgM assay have the potential to reduce false-positive rubella IgM results. Copyright © 2017 American Society for Microbiology.

Alcohol, caffeine, and nicotine consumption in adolescents: hair analysis versus self-report.

PubMed

Bertol, Elisabetta; Vaiano, Fabio; Boscolo-Berto, Rafael; Fioravanti, Alessia; Palumbo, Diego; Catalani, Valeria; Mari, Francesco; Patussi, Valentino; Serpelloni, Giovanni

2017-05-01

Clinical reliability of self-reported data for alcohol, caffeine, and nicotine consumptions is lacking, particularly in adolescents. To compare a self-report questionnaire and hair analysis to assess the reliability and effectiveness of the self-report. A cross-sectional study on 14-15-year-old Italian students (n = 874, 38% males, 62% females) was performed comparing self-reported data to hair analysis. The latter quantified hair concentrations of caffeine, nicotine, cotinine, ethyl glucuronide (EtG), and fatty acid ethyl esters (FAEEs) using mass spectrometry. Concordance between self-report and hair testing ranged from good to poor across substances and levels of use: poor for heavy alcohol intake (EtG: k = 0.36, 20 positive cases by hair analysis, false negative by self-report, 2.3% of total sample; FAEE k = 0.31, 25 positive cases, 2.9% of total sample); fair to poor for active smokers (k = 0.40, 125 positive cases, 14.3% of total sample); and moderate for caffeine (k = 0.57, 56 positive cases, 6.4% of total sample). Epidemiological studies on alcohol, caffeine, and nicotine consumption in adolescents may benefit from the inclusion of toxicological analysis on hair samples to overcome the under-reporting phenomenon of questionnaires and detect more cases of problematic substance use.

False Position, Double False Position and Cramer's Rule

ERIC Educational Resources Information Center

Boman, Eugene

2009-01-01

We state and prove the methods of False Position (Regula Falsa) and Double False Position (Regula Duorum Falsorum). The history of both is traced from ancient Egypt and China through the work of Fibonacci, ending with a connection between Double False Position and Cramer's Rule.

RBM10-TFE3 Renal Cell Carcinoma: A Potential Diagnostic Pitfall Due to Cryptic Intrachromosomal Xp11.2 Inversion Resulting in False-negative TFE3 FISH.

PubMed

Argani, Pedram; Zhang, Lei; Reuter, Victor E; Tickoo, Satish K; Antonescu, Cristina R

2017-05-01

Xp11 translocation renal cell carcinoma (RCC) are defined by chromosome translocations involving the Xp11 breakpoint which results in one of a variety of TFE3 gene fusions. TFE3 break-apart florescence in situ hybridization (FISH) assays are generally preferred to TFE3 immunohistochemistry (IHC) as a means of confirming the diagnosis in archival material, as FISH is less sensitive to the variable fixation which can result in false positive or false negative IHC. Prompted by a case report in the cytogenetics literature, we identify 3 cases of Xp11 translocation RCC characterized by a subtle chromosomal inversion involving the short arm of the X chromosome, resulting in an RBM10-TFE3 gene fusion. TFE3 rearrangement was not detected by conventional TFE3 break-apart FISH, but was suggested by strong diffuse TFE3 immunoreactivity in a clean background. We then developed novel fosmid probes to detect the RBM10-TFE3 gene fusion in archival material. These cases validate RBM10-TFE3 as a recurrent gene fusion in Xp11 translocation RCC, illustrate a source of false-negative TFE3 break-apart FISH, and highlight the complementary role of TFE3 IHC and TFE3 FISH.

[Telepathology in Mid-Norway].

PubMed

Haugen, O A; Halvorsen, T B; Aarset, H; Ovrehus, T A; Torp, S H; Edna, T H; Ruud, S

1999-01-30

Telepathology can provide frozen section service to hospitals without a pathology service of their own. Using a dynamic-robotic system with 6 ISDN B-channels (Telemed A200, AM Elektronikk A/S, Oslo, Norway), the pathologists at the University Hospital in Trondheim, Norway during a three-year period from 1995 successfully performed 116 diagnostic sessions for two rural Norwegian hospitals. In 90% of the cases a diagnosis was provided. There was no false positive diagnosis and only 3% false negative cases without clinical consequence. Deferred cases (10%) were mainly due to poor quality of the frozen sections and a conservative attitude among the pathologists. It is concluded that the diagnostic accuracy is good, but for safety reasons telepathology should be offered on a regular basis, so that the skills of the technicians and pathologists involved are kept up. In Mid-Norway, five more hospitals will be included in a telemedicine network comprising eight hospitals in the region.

Value of a Single-Tube Widal Test in Diagnosis of Typhoid Fever in Vietnam

PubMed Central

Parry, Christopher M.; Hoa, Nguyen Thi Tuyet; Diep, To Song; Wain, John; Chinh, Nguyen Tran; Vinh, Ha; Hien, Tran Tinh; White, Nicholas J.; Farrar, Jeremy J.

1999-01-01

The diagnostic value of an acute-phase single-tube Widal test for suspected typhoid fever was evaluated with 2,000 Vietnamese patients admitted to an infectious disease referral hospital between 1993 and 1998. Test patients had suspected typhoid fever and a blood culture positive for Salmonella typhi (n= 1,400) or Salmonella paratyphi A (n = 45). Control patients had a febrile illness for which another cause was confirmed (malaria [n = 103], dengue [n = 76], or bacteremia due to another microorganism [n = 156] or tetanus (n = 265). An O-agglutinin titer of ≥100 was found in 18% of the febrile controls and 7% of the tetanus patients. Corresponding values for H agglutinins were 8 and 1%, respectively. The O-agglutinin titer was ≥100 in 83% of the blood culture-positive typhoid fever cases, and the H-agglutinin titer was ≥100 in 67%. The disease prevalence in investigated patients in this hospital was 30.8% (95% confidence interval, 26.8 to 35.1%); at this prevalence, an elevated level of H agglutinins gave better positive predictive values for typhoid fever than did O agglutinins. With a cutoff titer of ≥200 for O agglutinin or ≥100 for H agglutinin, the Widal test would diagnose correctly 74% of the blood culture-positive cases of typhoid fever. However, 14% of the positive results would be false-positive, and 10% of the negative results would be false-negative. The Widal test can be helpful in the laboratory diagnosis of typhoid fever in Vietnam if interpreted with care. PMID:10449469

Large-scale benchmarking reveals false discoveries and count transformation sensitivity in 16S rRNA gene amplicon data analysis methods used in microbiome studies.

PubMed

Thorsen, Jonathan; Brejnrod, Asker; Mortensen, Martin; Rasmussen, Morten A; Stokholm, Jakob; Al-Soud, Waleed Abu; Sørensen, Søren; Bisgaard, Hans; Waage, Johannes

2016-11-25

There is an immense scientific interest in the human microbiome and its effects on human physiology, health, and disease. A common approach for examining bacterial communities is high-throughput sequencing of 16S rRNA gene hypervariable regions, aggregating sequence-similar amplicons into operational taxonomic units (OTUs). Strategies for detecting differential relative abundance of OTUs between sample conditions include classical statistical approaches as well as a plethora of newer methods, many borrowing from the related field of RNA-seq analysis. This effort is complicated by unique data characteristics, including sparsity, sequencing depth variation, and nonconformity of read counts to theoretical distributions, which is often exacerbated by exploratory and/or unbalanced study designs. Here, we assess the robustness of available methods for (1) inference in differential relative abundance analysis and (2) beta-diversity-based sample separation, using a rigorous benchmarking framework based on large clinical 16S microbiome datasets from different sources. Running more than 380,000 full differential relative abundance tests on real datasets with permuted case/control assignments and in silico-spiked OTUs, we identify large differences in method performance on a range of parameters, including false positive rates, sensitivity to sparsity and case/control balances, and spike-in retrieval rate. In large datasets, methods with the highest false positive rates also tend to have the best detection power. For beta-diversity-based sample separation, we show that library size normalization has very little effect and that the distance metric is the most important factor in terms of separation power. Our results, generalizable to datasets from different sequencing platforms, demonstrate how the choice of method considerably affects analysis outcome. Here, we give recommendations for tools that exhibit low false positive rates, have good retrieval power across effect sizes and case/control proportions, and have low sparsity bias. Result output from some commonly used methods should be interpreted with caution. We provide an easily extensible framework for benchmarking of new methods and future microbiome datasets.

Optimized molecular resolution of cross-contamination alerts in clinical mycobacteriology laboratories.

PubMed

Martín, Ana; Herranz, Marta; Lirola, Miguel Martínez; Fernández, Rosa Fernández; Bouza, Emilio; García de Viedma, Darío

2008-02-14

The phenomenon of misdiagnosing tuberculosis (TB) by laboratory cross-contamination when culturing Mycobacterium tuberculosis (MTB) has been widely reported and it has an obvious clinical, therapeutic and social impact. The final confirmation of a cross-contamination event requires the molecular identification of the same MTB strain cultured from both the potential source of the contamination and from the false-positive candidate. The molecular tool usually applied in this context is IS6110-RFLP which takes a long time to provide an answer, usually longer than is acceptable for microbiologists and clinicians to make decisions. Our purpose in this study is to evaluate a novel PCR-based method, MIRU-VNTR as an alternative to assure a rapid and optimized analysis of cross-contamination alerts. MIRU-VNTR was prospectively compared with IS6110-RFLP for clarifying 19 alerts of false positivity from other laboratories. MIRU-VNTR highly correlated with IS6110-RFLP, reduced the response time by 27 days and clarified six alerts unresolved by RFLP. Additionally, MIRU-VNTR revealed complex situations such as contamination events involving polyclonal isolates and a false-positive case due to the simultaneous cross-contamination from two independent sources. Unlike standard RFLP-based genotyping, MIRU-VNTR i) could help reduce the impact of a false positive diagnosis of TB, ii) increased the number of events that could be solved and iii) revealed the complexity of some cross-contamination events that could not be dissected by IS6110-RFLP.

[An integrated approach including paediatric and forensic medical expertise on suspicion of child abuse].

PubMed

Schouten, M C M; Karst, W A; van der Stel, H F; Teeuw, A H; van de Putte, E M

2016-01-01

A false accusation of child abuse has a major impact on child and family. Conversely, a missed diagnosis of child abuse may have significant and lifelong consequences for the child. For health professionals the assessment of the nature of the injury and differentiating between accidental and inflicted injury, disease manifestation or a physiological phenomenon can be challenging. For adequate determination of the cause of injury, an integrated approach including paediatric knowledge and forensic medical expertise is essential. Therefore, a national expertise centre for child abuse (LECK) was established in the Netherlands in 2014. The first results of this integrated approach are described and illustrated with three case reports. Case A, a 7-month-old boy with an accidental humerus fracture. Case B, an 8-year-old boy with a false positive suspicion of child abuse who was eventually diagnosed with Henoch-Schönlein syndrome. Case C, boy of 3 months with bruises and a metaphyseal fracture of the femur, both highly suspected of being inflicted injury.

Diagnosis of metastatic melanoma by fine-needle biopsy: analysis of 2,204 cases.

PubMed

Murali, Rajmohan; Doubrovsky, Anna; Watson, Geoffrey F; McKenzie, Paul R; Lee, C Soon; McLeod, Duncan J; Uren, Roger F; Stretch, Jonathan R; Saw, Robyn P M; Thompson, John F; Scolyer, Richard A

2007-03-01

Fine-needle biopsy (FNB) has been reported as a rapid, minimally invasive technique for the diagnosis of metastatic melanoma. The diagnostic accuracy of FNB was assessed in a consecutive series of 2,204 FNBs of clinically suspicious lesions from patients with previous primary melanomas treated at the Sydney Melanoma Unit, Sydney, Australia, between January 1992 and December 2002. The sensitivity and specificity of FNB were 96.3% and 98.9%, respectively. There were 5 false-positive cases (0.6%), which were verified as metastatic adenocarcinoma (3 cases) or reactive processes (organizing hematoma and chronic osteomyelitis, 1 each). False-negative diagnoses (6.7% of cases) were associated with a variety of clinicopathologic factors, including difficult-to-access anatomic sites (eg, high axilla or deep inguinal), small lesions, and lesional characteristics such asfibrosis, necrosis, or cystic change. FNB is a highly accurate, rapid, and cost-effective procedure for the diagnosis of metastatic melanoma and should be considered as the initial diagnostic procedure of choice in patients with melanoma with clinically suspected metastases.

Clinical outcome of subchromosomal events detected by whole‐genome noninvasive prenatal testing

PubMed Central

Helgeson, J.; Wardrop, J.; Boomer, T.; Almasri, E.; Paxton, W. B.; Saldivar, J. S.; Dharajiya, N.; Monroe, T. J.; Farkas, D. H.; Grosu, D. S.

2015-01-01

Abstract Objective A novel algorithm to identify fetal microdeletion events in maternal plasma has been developed and used in clinical laboratory‐based noninvasive prenatal testing. We used this approach to identify the subchromosomal events 5pdel, 22q11del, 15qdel, 1p36del, 4pdel, 11qdel, and 8qdel in routine testing. We describe the clinical outcomes of those samples identified with these subchromosomal events. Methods Blood samples from high‐risk pregnant women submitted for noninvasive prenatal testing were analyzed using low coverage whole genome massively parallel sequencing. Sequencing data were analyzed using a novel algorithm to detect trisomies and microdeletions. Results In testing 175 393 samples, 55 subchromosomal deletions were reported. The overall positive predictive value for each subchromosomal aberration ranged from 60% to 100% for cases with diagnostic and clinical follow‐up information. The total false positive rate was 0.0017% for confirmed false positives results; false negative rate and sensitivity were not conclusively determined. Conclusion Noninvasive testing can be expanded into the detection of subchromosomal copy number variations, while maintaining overall high test specificity. In the current setting, our results demonstrate high positive predictive values for testing of rare subchromosomal deletions. © 2015 The Authors. Prenatal Diagnosis published by John Wiley & Sons Ltd. PMID:26088833

Reliability of the anterior drawer test, the pivot shift test, and the Lachman test.

PubMed

Kim, S J; Kim, H K

1995-08-01

In 147 patients with arthroscopically proved chronic injuries of the anterior cruciate ligament, the anterior drawer test, the Lachman test, and the pivot shift test were done before operation under general or spinal anesthesia. Results of the anterior drawer test were positive in 79.6% of the patients, in 98.6% patients having the Lachman test, and in 89.8% of patients having the pivot shift test. In 19 cases (12.9%), arthroscopic examination showed reattachment of the proximally torn end of the anterior cruciate ligament to the posterior cruciate ligament. In these cases, results of the anterior drawer test were positive in 13 patients (68.4%), in 17 (89.5%) patients having the Lachman test, and in 12 patients (63.2%) having the pivot shift test. In 15 cases with a false negative pivot shift test, arthroscopy showed blockage of anterior subluxation of the lateral tibial condyle by a partially functioning portion of the anterior cruciate ligament, which was reattached to the posterior cruciate ligament in 7 cases. In 2 cases with a false negative Lachman test, there was firm reattachment of the torn end of the anterior cruciate ligament to the proximal portion of the posterior cruciate ligament combined with a bucket handle tear of the medial meniscus. The Lachman test was most sensitive in diagnosing chronic injuries of the anterior cruciate ligament. The pivot shift test was also sensitive but was influenced by many factors.

Reliability of automatic biometric iris recognition after phacoemulsification or drug-induced pupil dilation.

PubMed

Seyeddain, Orang; Kraker, Hannes; Redlberger, Andreas; Dexl, Alois K; Grabner, Günther; Emesz, Martin

2014-01-01

To investigate the reliability of a biometric iris recognition system for personal authentication after cataract surgery or iatrogenic pupil dilation. This was a prospective, nonrandomized, single-center, cohort study for evaluating the performance of an iris recognition system 2-24 hours after phacoemulsification and intraocular lens implantation (group 1) and before and after iatrogenic pupil dilation (group 2). Of the 173 eyes that could be enrolled before cataract surgery, 164 (94.8%) were easily recognized postoperatively, whereas in 9 (5.2%) this was not possible. However, these 9 eyes could be reenrolled and afterwards recognized successfully. In group 2, of a total of 184 eyes that were enrolled in miosis, a total of 22 (11.9%) could not be recognized in mydriasis and therefore needed reenrollment. No single case of false-positive acceptance occurred in either group. The results of this trial indicate that standard cataract surgery seems not to be a limiting factor for iris recognition in the large majority of cases. Some patients (5.2% in this study) might need "reenrollment" after cataract surgery. Iris recognition was primarily successful in eyes with medically dilated pupils in nearly 9 out of 10 eyes. No single case of false-positive acceptance occurred in either group in this trial. It seems therefore that iris recognition is a valid biometric method in the majority of cases after cataract surgery or after pupil dilation.

[Hepatic fine needle aspiration biopsy. Experience in the study of hepatic masses at the Salvador Zubiran National Institute of Nutrition].

PubMed

Angeles-Angeles, A; Gamboa-Domínguez, A; Velázquez Fernández, D; Muñoz-Fernández, L

1994-01-01

The results of 114 fine-needle aspiration biopsies (FNAB) of the liver performed during six years (1987-1992) at the Departament of Pathology of the Instituto Nacional de la Nutrición Salvador Zubirán are presented. All were done by radiologists under ultrasonographic (three cases) or computerized tomographic guidance (111 cases). In order to determine the diagnostic accuracy, diagnoses made by FNAB were compared with those made by histological examination (coarse biopsies or surgical specimens) and/or by other diagnostic procedures including the clinical follow-up. Six cases were excluded because clinical information was not available. In 92 cases (85.2%) a correct diagnosis was made, in six (5.5%) the sample was inadequate and in 10 (9.3%) the diagnosis made by FNAB was incorrect. The diagnoses made were as follows: hepatocarcinoma 44, metastatic carcinoma 27, inflammatory lesions 12, regeneration 10, normal eight, unclassified carcinoma five, and lymphoma two. The sensitivity was 96.2, specificity 93.1, positive predictive value 97.4, negative predictive value 90.0, accuracy 95.3 and prevalence 73.1. There were three false negative and two false positive for carcinoma. These figures are similar to those found by other authors. No relevant complications were observed. It is concluded that FNAB of the liver is a safe, inexpensive and reliable method in the diagnoses of liver masses.

Computerized tomography tailored for the assessment of microscopic hematuria.

PubMed

Lang, Erich K; Macchia, Richard J; Thomas, Raju; Ruiz-Deya, Gilberto; Watson, Richard A; Richter, Frank; Irwin R, Robert; Marberger, Michael; Mydlo, Jack; Lechner, Gerhard; Cho, Kyunghee C; Gayle, Brian

2002-02-01

We report the results of a multicenter study of arterial, corticomedullary, nephrographic and excretory phase helical computerized tomography (CT) for detecting and characterizing abnormalities causing asymptomatic microscopic hematuria. We evaluated 350 consecutive patients, including 216 men and 134 women 23 to 88 years old, with asymptomatic microscopic hematuria of undetermined cause at 4 medical centers. Patients with known urological pathology were excluded from study. We performed 4 helical CT sequences, including pre-enhancement phase imaging from kidney to symphysis pubis, arterial phase imaging of the kidney and lower pelvis, corticomedullary nephrographic phase imaging of the kidney and lower pelvis, and excretory phase imaging from kidney to symphysis pubis with 2 to 5 mm. collimation and 1 to 1.5 pitch. Of 171 proved lesions 158 were correctly diagnosed. There were 10 false-positive and 13 false-negative diagnoses, indicating 0.9239 sensitivity, 0.9441 specificity, 0.9404 positive and 0.9285 negative predictive values, (p <0.001). All cases of congenital renal lesions, calculous disease, ureteral lesion and neoplastic lesion of the bladder were correctly diagnosed, as were 40 of 41 inflammatory renal, 21 of 23 renal masses and 13 of 16 inflammatory bladder lesions. In 27 patients with renal calculi the study was limited to pre-enhancement spiral CT. A positive diagnosis rate of 45.1% (158 of 350 cases) for the causes of heretofore refractory cases of hematuria with high sensitivity and specificity attest to the effectiveness of our hematuria CT protocol and support its use.

Priming cases disturb visual search patterns in screening mammography

NASA Astrophysics Data System (ADS)

Lewis, Sarah J.; Reed, Warren M.; Tan, Alvin N. K.; Brennan, Patrick C.; Lee, Warwick; Mello-Thoms, Claudia

2015-03-01

Rationale and Objectives: To investigate the effect of inserting obvious cancers into a screening set of mammograms on the visual search of radiologists. Previous research presents conflicting evidence as to the impact of priming in scenarios where prevalence is naturally low, such as in screening mammography. Materials and Methods: An observer performance and eye position analysis study was performed. Four expert breast radiologists were asked to interpret two sets of 40 screening mammograms. The Control Set contained 36 normal and 4 malignant cases (located at case # 9, 14, 25 and 37). The Primed Set contained the same 34 normal and 4 malignant cases (in the same location) plus 2 "primer" malignant cases replacing 2 normal cases (located at positions #20 and 34). Primer cases were defined as lower difficulty cases containing salient malignant features inserted before cases of greater difficulty. Results: Wilcoxon Signed Rank Test indicated no significant differences in sensitivity or specificity between the two sets (P > 0.05). The fixation count in the malignant cases (#25, 37) in the Primed Set after viewing the primer cases (#20, 34) decreased significantly (Z = -2.330, P = 0.020). False-Negatives errors were mostly due to sampling in the Primed Set (75%) in contrast to in the Control Set (25%). Conclusion: The overall performance of radiologists is not affected by the inclusion of obvious cancer cases. However, changes in visual search behavior, as measured by eye-position recording, suggests visual disturbance by the inclusion of priming cases in screening mammography.

MRI in the diagnosis and surgical management of abnormal placentation.

PubMed

Palacios-Jaraquemada, José Miguel; Bruno, Claudio Hernán; Martín, Eduardo

2013-04-01

To determine the usefulness of placental magnetic resonance imaging (MRI) in the diagnosis and surgical management of abnormal placentation. Retrospective follow-up. Buenos Aires, Argentina. 547 pregnant women. In all cases, a direct and reliable description of abnormal placentation features was obtained by the operating surgeon. Placental MRI was analyzed according to: (1) primary description, (2) invasion topography, (3) modification required to the surgical tactics or techniques and (4) by positive and negative predictive values. Ultrasound and MRI findings were compared with surgical results, which were considered a final diagnosis in relation to primary diagnostic indications. Placental MRI was obtained because of diagnostic doubt in 78 cases, for deep invasion diagnosis in 148 cases and to define the invasion area in 346 cases. Placental MRI allowed accurate demarcation and assessment of the degree of placental invasion, parametrial involvement and cervico-trigonal vascular hyperplasia, permitting changes in the surgical tactical approach. Ultrasound and MRI differences were associated with placenta previa, uterine scar thinning and use of different criteria for placental invasion through definitions or terminology. Six cases of false-negative and 11 of false-positive findings were reported. Placental MRI provides excellent characterization of the degree and extension of placental invasion. Its usefulness in cases of adherent placentation is directly associated to the therapeutic measures, especially where dissection maneuvers are needed. Diagnostic differences between ultrasound and MRI related to the presence or not of placenta previa and uterine scar thinning. © 2012 The Authors Acta Obstetricia et Gynecologica Scandinavica © 2012 Nordic Federation of Societies of Obstetrics and Gynecology.

Modeling Kepler Transit Light Curves as False Positives: Rejection of Blend Scenarios for Kepler-9, and Validation of Kepler-9 d, a Super-Earth-Size Planet in a Multiple System

NASA Technical Reports Server (NTRS)

Torres, Guillermo; Fressin, Francois; Batalha, Natalie M.; Borucki, William J.; Brown, Timothy M.; Bryson, Stephen T.; Buchhave, Lars A.; Charbonneau, David; Ciardi, David R.; Dunham, Edward W.;

Fine needle aspiration cytology of oral and oropharyngeal lesions with an emphasis on the diagnostic utility and pitfalls.

PubMed

Gupta, Nalini; Banik, Tarak; Rajwanshi, Arvind; Radotra, Bishan D; Panda, Naresh; Dey, Pranab; Srinivasan, Radhika; Nijhawan, Raje

2012-01-01

This study was undertaken to evaluate the diagnostic utility and pitfalls of fine needle aspiration cytology (FNAC) in oral and oropharyngeal lesions. This was a retrospective audit of oral and oropharyngeal lesions diagnosed with FNAC over a period of six years (2005-2010). Oral/oropharyngeal lesions [n=157] comprised 0.35% of the total FNAC load. The age ranged 1-80 years with the male: female ratio being 1.4:1. Aspirates were inadequate in 7% cases. Histopathology was available in 73/157 (46.5%) cases. Palate was the most common site of involvement [n=66] followed by tongue [n=35], buccal mucosa [n=18], floor of the mouth [n=17], tonsil [n=10], alveolus [n=5], retromolar trigone [n=3], and posterior pharyngeal wall [n=3]. Cytodiagnoses were categorized into infective/inflammatory lesions and benign cysts, and benign and malignant tumours. Uncommon lesions included ectopic lingual thyroid and adult rhabdomyoma of tongue, and solitary fibrous tumor (SFT), and leiomyosarcoma in buccal mucosa. A single false-positive case was dense inflammation with squamous cells misinterpreted as squamous cell carcinoma (SCC) on cytology. There were eight false-negative cases mainly due to sampling error. One false-negative case due to interpretation error was in a salivary gland tumor. The sensitivity of FNAC in diagnosing oral/oropharyngeal lesions was 71.4%; specificity was 97.8% with diagnostic accuracy of 87.7%. Salivary gland tumors and squamous cell carcinoma (SCC) are the most common lesions seen in the oral cavity. FNAC proves to be highly effective in diagnosing the spectrum of different lesions in this region. Sampling error is the main cause of false-negative cases in this region.

Nested association mapping for dissecting complex traits using Peanut 58K SNP array

USDA-ARS?s Scientific Manuscript database

Genome-wide association studies (GWAS) and linkage mapping have been the two most predominant strategies to dissect complex traits, but are limited by the occurrence of false positives reported for GWAS, and low resolution in the case of linkage analysis. This has led to the development of a joint a...

Applying Jlint to Space Exploration Software

NASA Technical Reports Server (NTRS)

Artho, Cyrille; Havelund, Klaus

2004-01-01

Java is a very successful programming language which is also becoming widespread in embedded systems, where software correctness is critical. Jlint is a simple but highly efficient static analyzer that checks a Java program for several common errors, such as null pointer exceptions, and overflow errors. It also includes checks for multi-threading problems, such as deadlocks and data races. The case study described here shows the effectiveness of Jlint in find-false positives in the multi-threading warnings gives an insight into design patterns commonly used in multi-threaded code. The results show that a few analysis techniques are sufficient to avoid almost all false positives. These techniques include investigating all possible callers and a few code idioms. Verifying the correct application of these patterns is still crucial, because their correct usage is not trivial.

False positive results using calcitonin as a screening method for medullary thyroid carcinoma.

PubMed

Batista, Rafael Loch; Toscanini, Andrea Cecilia; Brandão, Lenine Garcia; Cunha-Neto, Malebranche Berardo C

2013-05-01

The role of serum calcitonin as part of the evaluation of thyroid nodules has been widely discussed in literature. However there still is no consensus of measurement of calcitonin in the initial evaluation of a patient with thyroid nodule. Problems concerning cost-benefit, lab methods, false positive and low prevalence of medullary thyroid carcinoma (MTC) are factors that limit this approach. We have illustrated two cases where serum calcitonin was used in the evaluation of thyroid nodule and rates proved to be high. A stimulation test was performed, using calcium as secretagogue, and calcitonin hyper-stimulation was confirmed, but anatomopathologic examination did not evidence medullar neoplasia. Anatomopathologic diagnosis detected Hashimoto thyroiditis in one case and adenomatous goiter plus an occult papillary thyroid carcinoma in the other one. Recommendation for routine use of serum calcitonin in the initial diagnostic evaluation of a thyroid nodule, followed by a confirming stimulation test if basal serum calcitonin is showed to be high, is the most currently recommended approach, but questions concerning cost-benefit and possibility of diagnosis error make the validity of this recommendation discussible.

Lymphadenopathy resulting from acute toxoplasmosis mimicking relapse of non-Hodgkin's lymphoma on fluorodeoxyglucose positron emission tomography/computed tomography.

PubMed

Joshi, Prathamesh; Lele, Vikram; Mahajan, Pravin

2012-01-01

We report a case documenting fluorodeoxyglucose (FDG) accumulation in cervical, supraclavicular and axillary lymph nodes resulting from acute toxoplasmosis. A 50-year-old Indian female with history of non-Hodgkin's lymphoma (NHL) of left breast, postchemotherapy status, was found to have hypermetabolic right cervical, supraclavicular and axillary lymph nodes on a surveillance FDG positron emission tomography/computed tomography (PET/CT) scan. Her previous two PET/CT scans were unremarkable with no evidence of metabolically active disease. Therefore, a differential diagnosis of relapse of NHL versus infectious/inflammatory pathology was raised in the report. Biopsy of axillary lymph node demonstrated features characteristic of toxoplasmosis. The serological test results were also compatible with acute toxoplasmosis infection. Infective and inflammatory diseases are known to accumulate FDG, resulting in false positives for malignancy. This case demonstrates lymph nodal toxoplasmosis as a potential cause of false positive FDG PET/CT findings in patients with known malignancy and highlights the importance of histopathological and laboratory correlation for the accurate interpretation of FDG PET/CT scans.

Accurate Identification of ALK Positive Lung Carcinoma Patients: Novel FDA-Cleared Automated Fluorescence In Situ Hybridization Scanning System and Ultrasensitive Immunohistochemistry

PubMed Central

Conde, Esther; Suárez-Gauthier, Ana; Benito, Amparo; Garrido, Pilar; García-Campelo, Rosario; Biscuola, Michele; Paz-Ares, Luis; Hardisson, David; de Castro, Javier; Camacho, M. Carmen; Rodriguez-Abreu, Delvys; Abdulkader, Ihab; Ramirez, Josep; Reguart, Noemí; Salido, Marta; Pijuán, Lara; Arriola, Edurne; Sanz, Julián; Folgueras, Victoria; Villanueva, Noemí; Gómez-Román, Javier; Hidalgo, Manuel; López-Ríos, Fernando

2014-01-01

Background Based on the excellent results of the clinical trials with ALK-inhibitors, the importance of accurately identifying ALK positive lung cancer has never been greater. However, there are increasing number of recent publications addressing discordances between FISH and IHC. The controversy is further fuelled by the different regulatory approvals. This situation prompted us to investigate two ALK IHC antibodies (using a novel ultrasensitive detection-amplification kit) and an automated ALK FISH scanning system (FDA-cleared) in a series of non-small cell lung cancer tumor samples. Methods Forty-seven ALK FISH-positive and 56 ALK FISH-negative NSCLC samples were studied. All specimens were screened for ALK expression by two IHC antibodies (clone 5A4 from Novocastra and clone D5F3 from Ventana) and for ALK rearrangement by FISH (Vysis ALK FISH break-apart kit), which was automatically captured and scored by using Bioview's automated scanning system. Results All positive cases with the IHC antibodies were FISH-positive. There was only one IHC-negative case with both antibodies which showed a FISH-positive result. The overall sensitivity and specificity of the IHC in comparison with FISH were 98% and 100%, respectively. Conclusions The specificity of these ultrasensitive IHC assays may obviate the need for FISH confirmation in positive IHC cases. However, the likelihood of false negative IHC results strengthens the case for FISH testing, at least in some situations. PMID:25248157

Impact of round-the-clock CSF Gram stain on empirical therapy for suspected central nervous system infections.

PubMed

Tissot, F; Prod'hom, G; Manuel, O; Greub, G

2015-09-01

The impact of round-the-clock cerebrospinal fluid (CSF) Gram stain on overnight empirical therapy for suspected central nervous system (CNS) infections was investigated. All consecutive overnight CSF Gram stains between 2006 and 2011 were included. The impact of a positive or a negative test on empirical therapy was evaluated and compared to other clinical and biological indications based on institutional guidelines. Bacterial CNS infection was documented in 51/241 suspected cases. Overnight CSF Gram stain was positive in 24/51. Upon validation, there were two false-positive and one false-negative results. The sensitivity and specificity were 41 and 99 %, respectively. All patients but one had other indications for empirical therapy than Gram stain alone. Upon obtaining the Gram result, empirical therapy was modified in 7/24, including the addition of an appropriate agent (1), addition of unnecessary agents (3) and simplification of unnecessary combination therapy (3/11). Among 74 cases with a negative CSF Gram stain and without formal indication for empirical therapy, antibiotics were withheld in only 29. Round-the-clock CSF Gram stain had a low impact on overnight empirical therapy for suspected CNS infections and was associated with several misinterpretation errors. Clinicians showed little confidence in CSF direct examination for simplifying or withholding therapy before definite microbiological results.

Comparative analysis of 99mTc-depreotide and 99mTc-EDDA/HYNIC-TOC thorax scintigrams acquired for the purpose of differential diagnosis of solitary pulmonary nodules.

PubMed

Płachcińska, Anna; Mikołajczak, Renata; Kozak, Józef; Rzeszutek, Katarzyna; Kuśmierek, Jacek

2006-01-01

Aiming at comparison of diagnostic efficacy of 2 radiopharmaceuticals: 99mTc-depreotide (Neospect, Amersham) and 99mTc-EDDA/HYNIC-Tyr3-octreotide (Tektrotyd, Polatom), in differentiation between malignant and benign etiology of solitary pulmonary nodules (SPNs), radionuclide studies with 2 radiotracers were performed in 18 patients. For both radiopharmaceuticals the same acquisition and processing protocols were applied. Studies were acquired with SPECT technique, after administration of 740 MBq of activity. Scintigrams were assessed visually, as: positive (+), equivocal (+/-) and negative (-). Additionally, uptake intensity of both radiotracers in nodules was assessed semiquantitatively, using a tumour-to-background ratio. Verification of scintigraphic results was based in 14 cases upon a pathological examination of tumour samples (histopathology) and in the remaining 4 - on clinical observation and bacteriological studies. Normal scintigrams obtained with both radiopharmaceuticals differed significantly. 99mTc-depreotide was markedly accumulated in spine, sternum, ribs and lungs (mean lung/heart ratio = 2.2). This accumulation was not observed on 99mTc- -EDDA/HYNIC-TOC scintigrams (mean lung/heart ratio = 0.7). In 6 patients a malignant etiology--lung cancer--was revealed (5--adenocarcinoma, 1--squamous cell) and the other 12 cases turned out to be benign (4 hamartomas, 3 tuberculomas, a tuberculous infiltrate, an alien body with inflammatory reaction, a hyperplasia of lymphatic tissue and 2 cases of unknown etiology, from which one had a stable size and the other resolved during a 6 month observation period). In all 6 cases of lung cancer positive results were obtained with both tracers. Moreover, in 2 patients metastases in mediastinum could be observed on scintigrams obtained with both radiopharmaceuticals. From among 12 cases of benign etiology 6 99mTc-depreotide scintigrams were true negative, 1--equivocal and 5--false positive, whereas 6 99mTc-EDDA/HYNIC-TOC scintigrams were true negative, 4--equivocal and 2 false positive. Moreover, 99mTc-depreotide additionally revealed mediastinal and hilar lesions in 9 patients with benign lesions and 99mTc-EDDA/HYNIC-TOC - in 8. A visual comparison of scintigrams revealed a higher quality of 99mTc-Depreotide images in comparison with 99mTc-EDDA/HYNIC-TOC ones. 99mTc-Depreotide showed a higher than 99mTc-EDDA/HYNIC-TOC accumulation in lung tumours compared with blood pool (heart) - 4.5 (s.d. 1.05) and 1.8 (s.d. 0.29), respectively (p < 0.05). However, mean values of tumour-to-lung-background ratio were equal for both radiotracers (2.2 in malignant and 1.4 in benign lesions, respectively). A statistically significantly higher non-uniformity of counts inside lung background regions was found on 99mTc-EDDA/HYNIC-TOC scintigrams than on 99mTc-depreotide ones (16.4% vs. 11.4%; p < 0.01). Although both radiopharmaceuticals show similar diagnostic efficacy in differentiation of SPNs, a tendency toward a higher number of false positive results on 99mTc-depreotide scintigrams probably leads to a lower specificity. Better statistical quality of 99mTc-depreotide scintigrams facilitates their interpretation and a distinct outline of lungs simplify localization of lesions. A substantial number of false positive lesions in mediastinal and hilar regions in patients without a neoplastic process hamper the usefulness of both radiotracers for effective detection of lung cancer metastases to lymph nodes.

The reliability of fine-needle aspiration biopsy in terms of malignancy in patients with Hashimoto thyroiditis.

PubMed

Kapan, Murat; Onder, Akin; Girgin, Sadullah; Ulger, Burak Veli; Firat, Ugur; Uslukaya, Omer; Oguz, Abdullah

2015-02-01

The aim of this study was to analyze the presence of malignancy in patients with Hashimoto's thyroiditis and to investigate the reliability of preoperative fine-needle aspiration biopsy (FNAB). The retrospective study included 44 patients who were operated on for nodular goiter between December 2010 and October 2011. The patients underwent thyroidectomy following a cytologic analysis plus FNAB. Hashimoto's thyroiditis was confirmed on histopathology in all patients. FNAB results were defined as benign in 14 (31.8%), suspicion for malignancy in 17 (38.6%), malignant in 9 (20.5%), and inadequate in 4 (9.1%). Following the thyroidectomy, presence of papillary thyroid carcinoma and follicular variant of papillary thyroid carcinoma were detected in 10 patients (22.7%) and 1 (2.3%) patient, respectively. The FNAB results were interpreted in terms of malignancy, which revealed the sensitivity as 80%; specificity, 40%; false positives, 69.2%; false negatives, 14.3%; positive predictive value, 31.8%; negative predictive value, 85.7%; and diagnostic accuracy, 50%. The coexistence of Hashimoto's thyroiditis with papillary thyroid carcinoma is quite common. The FNAB results for such cases are hard to evaluate, and they are likely to increase the number of false positives.

[Tropheryma whipplei and Whipple disease: false positive PCR detections of Tropheryma whipplei in diagnostic samples are rare].

PubMed

Le Scanff, J; Gaultier, J B; Durand, D Vital; Durieu, I; Celard, M; Benito, Y; Vandenesch, F; Rousset, H

2008-11-01

PCR can be used to detect T. whipplei (Tw) in samples from variable tissue types and body fluids. We report clinical, evolutive characteristics and final diagnosis in patients with positive Tw PCR assay. Retrospective study of Tw PCR realized since 10years in a microbiology laboratory. Twenty-five Tw PCR assays were positive among 200 realized. Diagnosis was not confirmed in six cases. One patient was missing for follow up. Eighteen patients presented with Whipple's disease. Among these 18 patients, 14 had a classic Whipple's disease, three patients presented an endocarditis and one patient isolated neurological manifestations. Ten patients presented fever, seven a weight loss and 12 joint involvement. Four patients presented cutaneous manifestations, only six had gastrointestinal symptoms. Neurological involvement was reported in five cases, pulmonary symptoms in four cases, cardiac involvement in six cases and ocular signs in two cases. Anemia was reported in four patients and elevated levels of acute-phase reactants in 14 cases. Positive predictive value of Tw PCR for Whipple's disease diagnosis was 75%. Thirteen patients had a good evolution with antibiotics. Three patients presented recurrence and two cases with cardiovascular involvement died. Whipple's disease is rare but often mentioned in internist experience. The diagnosis should be every time confirmed. Tw PCR assay is an important diagnostic tool but is not sufficient to establish the diagnosis and must be interpreted with histopathology and immunohistochemical testing results.

Computer-Aided Diagnostic (CAD) Scheme by Use of Contralateral Subtraction Technique

NASA Astrophysics Data System (ADS)

Nagashima, Hiroyuki; Harakawa, Tetsumi

We developed a computer-aided diagnostic (CAD) scheme for detection of subtle image findings of acute cerebral infarction in brain computed tomography (CT) by using a contralateral subtraction technique. In our computerized scheme, the lateral inclination of image was first corrected automatically by rotating and shifting. The contralateral subtraction image was then derived by subtraction of reversed image from original image. Initial candidates for acute cerebral infarctions were identified using the multiple-thresholding and image filtering techniques. As the 1st step for removing false positive candidates, fourteen image features were extracted in each of the initial candidates. Halfway candidates were detected by applying the rule-based test with these image features. At the 2nd step, five image features were extracted using the overlapping scale with halfway candidates in interest slice and upper/lower slice image. Finally, acute cerebral infarction candidates were detected by applying the rule-based test with five image features. The sensitivity in the detection for 74 training cases was 97.4% with 3.7 false positives per image. The performance of CAD scheme for 44 testing cases had an approximate result to training cases. Our CAD scheme using the contralateral subtraction technique can reveal suspected image findings of acute cerebral infarctions in CT images.

Automated detection of extradural and subdural hematoma for contrast-enhanced CT images in emergency medical care

NASA Astrophysics Data System (ADS)

Hara, Takeshi; Matoba, Naoto; Zhou, Xiangrong; Yokoi, Shinya; Aizawa, Hiroaki; Fujita, Hiroshi; Sakashita, Keiji; Matsuoka, Tetsuya

2007-03-01

We have been developing the CAD scheme for head and abdominal injuries for emergency medical care. In this work, we have developed an automated method to detect typical head injuries, rupture or strokes of brain. Extradural and subdural hematoma region were detected by comparing technique after the brain areas were registered using warping. We employ 5 normal and 15 stroke cases to estimate the performance after creating the brain model with 50 normal cases. Some of the hematoma regions were detected correctly in all of the stroke cases with no false positive findings on normal cases.

Free digital image analysis software helps to resolve equivocal scores in HER2 immunohistochemistry.

PubMed

Helin, Henrik O; Tuominen, Vilppu J; Ylinen, Onni; Helin, Heikki J; Isola, Jorma

2016-02-01

Evaluation of human epidermal growth factor receptor 2 (HER2) immunohistochemistry (IHC) is subject to interobserver variation and lack of reproducibility. Digital image analysis (DIA) has been shown to improve the consistency and accuracy of the evaluation and its use is encouraged in current testing guidelines. We studied whether digital image analysis using a free software application (ImmunoMembrane) can assist in interpreting HER2 IHC in equivocal 2+ cases. We also compared digital photomicrographs with whole-slide images (WSI) as material for ImmunoMembrane DIA. We stained 750 surgical resection specimens of invasive breast cancers immunohistochemically for HER2 and analysed staining with ImmunoMembrane. The ImmunoMembrane DIA scores were compared with the originally responsible pathologists' visual scores, a researcher's visual scores and in situ hybridisation (ISH) results. The originally responsible pathologists reported 9.1 % positive 3+ IHC scores, for the researcher this was 8.4 % and for ImmunoMembrane 9.5 %. Equivocal 2+ scores were 34 % for the pathologists, 43.7 % for the researcher and 10.1 % for ImmunoMembrane. Negative 0/1+ scores were 57.6 % for the pathologists, 46.8 % for the researcher and 80.8 % for ImmunoMembrane. There were six false positive cases, which were classified as 3+ by ImmunoMembrane and negative by ISH. Six cases were false negative defined as 0/1+ by IHC and positive by ISH. ImmunoMembrane DIA using digital photomicrographs and WSI showed almost perfect agreement. In conclusion, digital image analysis by ImmunoMembrane can help to resolve a majority of equivocal 2+ cases in HER2 IHC, which reduces the need for ISH testing.

Evaluation of the perianal muscular complex in the prenatal diagnosis of anorectal atresia in a high-risk population.

PubMed

Ochoa, J H; Chiesa, M; Vildoza, R P; Wong, A E; Sepulveda, W

2012-05-01

To investigate whether sonographic identification of the fetal perianal muscular complex (PAMC) is of value in the prenatal detection of anorectal atresia in a high-risk population. During an 8-year study period, a total of 189 pregnancies at high risk for fetal anorectal atresia were prospectively examined for the presence/absence of the PAMC on axial ultrasound views of the fetal perineum. The prenatal findings were confirmed postnatally or at the time of postmortem examination. The median gestational age at examination was 27 (range, 15-37) weeks. The PAMC was identified in 175 fetuses, all of which had a normal anorectal canal at the time of delivery or at postmortem examination. The PAMC was not identified prenatally in the 14 remaining cases, and the anus was absent in 11 fetuses with anorectal atresia and in two with urorectal septum malformation sequence. There was one false-positive case, in which the anus was anatomically and functionally normal but ectopically located, opening into the vaginal vestibule. Among these 14 cases of anorectal malformation, prenatal dilatation of the distal bowel was seen in nine (64.3%) and intraluminal calcified meconium or enterolithiasis in five (35.7%). Overall, absent PAMC on prenatal sonography in this high-risk population had a sensitivity of 100%, specificity of 99%, true-positive rate of 93% and false-positive rate of 7% for the diagnosis of anorectal atresia. In a high-risk population, the absence of PAMC seems to be a highly sensitive and specific sonographic marker for anorectal atresia. The role of routine sonographic identification of the PAMC at the second-trimester scan to screen for cases of isolated anal atresia remains to be determined. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.

Occupancy models for data with false positive and false negative errors and heterogeneity across sites and surveys

Treesearch

Paige F.B. Ferguson; Michael J. Conroy; Jeffrey Hepinstall-Cymerman; Nigel Yoccoz

2015-01-01

False positive detections, such as species misidentifications, occur in ecological data, although many models do not account for them. Consequently, these models are expected to generate biased inference.The main challenge in an analysis of data with false positives is to distinguish false positive and false negative...

Clinical impact of reducing routine blood culture incubation time from 7 to 5 days.

PubMed

Marginson, Michael J; Daveson, Kathryn L; Kennedy, Karina J

2014-12-01

The aim of this study was to determine the clinical impact of reducing the blood culture incubation protocol from 7 to 5 days.A laboratory data extraction identified positive blood cultures occurring after 5 or more days of incubation at Canberra Hospital, Australia between 1 January 2001 and 31 August 2011. Isolates were identified as clinically significant using a pre-existing prospective bacteraemia database. Medical records review determined whether the positive result affected clinical management.Positive blood cultures after 5 or more days of incubation accounted for 2.65% (423/15979) of all positive blood cultures, although the majority were false positives or contaminants. Eighty-five were significant/indeterminate, representing an average of eight cases per year or 0.47% (85/15979) of all positive blood cultures sets. Forty-three were isolated for the first time, representing 1.1% of all significant/indeterminate blood culture episodes. Fungi and anaerobic bacteria compromised over 50% of isolates. In 26 cases (2.4 cases per year), the culture result led to a change in patient management.A 7 day incubation protocol is preferable due to late isolation of organisms; however, if space is required to accommodate increasing blood culture numbers, reducing to a 5 or 6 day protocol would miss only a small percentage of clinically significant isolates.

Risk of breast cancer with CXCR4-using HIV defined by V3 loop sequencing.

PubMed

Goedert, James J; Swenson, Luke C; Napolitano, Laura A; Haddad, Mojgan; Anastos, Kathryn; Minkoff, Howard; Young, Mary; Levine, Alexandra; Adeyemi, Oluwatoyin; Seaberg, Eric C; Aouizerat, Bradley; Rabkin, Charles S; Harrigan, P Richard; Hessol, Nancy A

2015-01-01

Evaluate the risk of female breast cancer associated with HIV-CXCR4 (X4) tropism as determined by various genotypic measures. A breast cancer case-control study, with pairwise comparisons of tropism determination methods, was conducted. From the Women's Interagency HIV Study repository, one stored plasma specimen was selected from 25 HIV-infected cases near the breast cancer diagnosis date and 75 HIV-infected control women matched for age and calendar date. HIV-gp120 V3 sequences were derived by Sanger population sequencing (PS) and 454-pyro deep sequencing (DS). Sequencing-based HIV-X4 tropism was defined using the geno2pheno algorithm, with both high-stringency DS [false-positive rate (3.5) and 2% X4 cutoff], and lower stringency DS (false-positive rate, 5.75 and 15% X4 cutoff). Concordance of tropism results by PS, DS, and previously performed phenotyping was assessed with kappa (κ) statistics. Case-control comparisons used exact P values and conditional logistic regression. In 74 women (19 cases, 55 controls) with complete results, prevalence of HIV-X4 by PS was 5% in cases vs 29% in controls (P = 0.06; odds ratio, 0.14; confidence interval: 0.003 to 1.03). Smaller case-control prevalence differences were found with high-stringency DS (21% vs 36%, P = 0.32), lower stringency DS (16% vs 35%, P = 0.18), and phenotyping (11% vs 31%, P = 0.10). HIV-X4 tropism concordance was best between PS and lower stringency DS (93%, κ = 0.83). Other pairwise concordances were 82%-92% (κ = 0.56-0.81). Concordance was similar among cases and controls. HIV-X4 defined by population sequencing (PS) had good agreement with lower stringency DS and was significantly associated with lower odds of breast cancer.

Diagnostic accuracy of frozen-section analysis of cancer-containing bladder transurethral resection specimens for the presence of muscularis propria invasion.

PubMed

Goyal, Rajen; Zhu, Bing; Parimi, Vamsi; Lin, Xiaoqi; Rohan, Stephen M

2014-07-01

Frozen section (FS) consultation is generally an accurate diagnostic modality. At our institution, we are frequently asked to assess transurethral resection specimens (TURBT) at FS for muscularis propria (MP) invasion by carcinoma. This study documents our experience in evaluating cancer-containing TURBT specimens at FS for MP invasion. 32 TURBT sent for FS from 2008-2010 were identified. The FS and permanent section (PS) diagnoses were reviewed. Cases excluded from the calculation of test performance included: (1) cases without cancer on FS or PS slides, (2) FS diagnosis deferred, (3) cases without MP on FS and subsequent PS slides. Sensitivity (SEN), specificity (SPEC), positive predictive value (PPV), and negative predictive value (NPV) for identifying MP invasion at FS were calculated. In 6 cases, no cancer was present in FS or PS slides (18%). The FS diagnosis was deferred on 3 cases (9%). In one case (3%) MP was not present in the FS or the subsequent PS slides. Of the remaining 22 cases, 2 false positive and 6 false negative diagnoses of MP invasion were identified. The test performance for FS assessment of MP invasion in TURB were SEN=33%, SPEC=84%, PPV=60%, and NPV=64%. Identifying MP invasion on PS can be difficult, and our results suggest that this is more difficult at FS. Though this study is based on small numbers, our results point to the conclusion that examination of TURBT specimens for MP invasion is best done on PS. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

DCT-based iris recognition.

PubMed

Monro, Donald M; Rakshit, Soumyadip; Zhang, Dexin

2007-04-01

This paper presents a novel iris coding method based on differences of discrete cosine transform (DCT) coefficients of overlapped angular patches from normalized iris images. The feature extraction capabilities of the DCT are optimized on the two largest publicly available iris image data sets, 2,156 images of 308 eyes from the CASIA database and 2,955 images of 150 eyes from the Bath database. On this data, we achieve 100 percent Correct Recognition Rate (CRR) and perfect Receiver-Operating Characteristic (ROC) Curves with no registered false accepts or rejects. Individual feature bit and patch position parameters are optimized for matching through a product-of-sum approach to Hamming distance calculation. For verification, a variable threshold is applied to the distance metric and the False Acceptance Rate (FAR) and False Rejection Rate (FRR) are recorded. A new worst-case metric is proposed for predicting practical system performance in the absence of matching failures, and the worst case theoretical Equal Error Rate (EER) is predicted to be as low as 2.59 x 10(-4) on the available data sets.

Detection of right-to-left shunts: comparison between the International Consensus and Spencer Logarithmic Scale criteria.

PubMed

Lao, Annabelle Y; Sharma, Vijay K; Tsivgoulis, Georgios; Frey, James L; Malkoff, Marc D; Navarro, Jose C; Alexandrov, Andrei V

2008-10-01

International Consensus Criteria (ICC) consider right-to-left shunt (RLS) present when Transcranial Doppler (TCD) detects even one microbubble (microB). Spencer Logarithmic Scale (SLS) offers more grades of RLS with detection of >30 microB corresponding to a large shunt. We compared the yield of ICC and SLS in detection and quantification of a large RLS. We prospectively evaluated paradoxical embolism in consecutive patients with ischemic strokes or transient ischemic attack (TIA) using injections of 9 cc saline agitated with 1 cc of air. Results were classified according to ICC [negative (no microB), grade I (1-20 microB), grade II (>20 microB or "shower" appearance of microB), and grade III ("curtain" appearance of microB)] and SLS criteria [negative (no microB), grade I (1-10 microB), grade II (11-30 microB), grade III (31100 microB), grade IV (101300 microB), grade V (>300 microB)]. The RLS size was defined as large (>4 mm) using diameter measurement of the septal defects on transesophageal echocardiography (TEE). TCD comparison to TEE showed 24 true positive, 48 true negative, 4 false positive, and 2 false negative cases (sensitivity 92.3%, specificity 92.3%, positive predictive value (PPV) 85.7%, negative predictive value (NPV) 96%, and accuracy 92.3%) for any RLS presence. Both ICC and SLS were 100% sensitive for detection of large RLS. ICC and SLS criteria yielded a false positive rate of 24.4% and 7.7%, respectively when compared to TEE. Although both grading scales provide agreement as to any shunt presence, using the Spencer Scale grade III or higher can decrease by one-half the number of false positive TCD diagnoses to predict large RLS on TEE.

Evaluation of the black light test for screening aflatoxin-contaminated maize in the Brazilian food industry.

PubMed

Gloria, E M; Fonseca, H; Calori-Domingues, M A; Souza, I M

1998-01-01

The results of the black light test for aflatoxin-contaminated maize carried out in a large food factory in the State of São Paulo was evaluated against bi-directional thin layer chromatography (TLC) analysis for 286 samples of maize. All 286 samples were accepted by the black light test (< 7 fluorescent points), however, the results from TLC analysis showed that 96 samples were contaminated and 14 showed aflatoxin B1 contamination levels higher than 20 micrograms/kg. There were 14 false negative results and no false positives and out of the 14 samples, six did not show visible fluorescent points. If the rejection criterion of one or more fluorescent points were applied, the six samples would be accepted by the black light test. But, in this case, 95 samples would be rejected and 87 results would be false positives because they did not have contamination levels over 20 micrograms/kg which is the acceptance limit of the black light test. The results indicate that the black light test, as utilized by this factory, was not able to indicate lots with possible contamination and the black light test, as recommended in the literature, would produce a high number of false positives. It is necessary to make more studies on the use of black light as a screening test for possible aflatoxin B1-contaminated maize.

False negative PCR despite high levels of JC virus DNA in spinal fluid: Implications for diagnostic testing

PubMed Central

Landry, Marie L.; Eid, Tore; Bannykh, Serguei; Major, Eugene

2009-01-01

Genome amplification methods such as polymerase chain reaction (PCR) have revolutionized our ability to detect viruses in spinal fluids of patients with neurologic diseases. It is not as well appreciated among clinicians that PCR protocols, quality assurance, and technical expertise vary significantly among laboratories. In a multi-laboratory blinded study of herpes simplex virus PCR, the most widely used and best validated CSF PCR assay, low-level positives were often missed and false positives were not uncommon [Schloss L, van Loon AM, Cinque P, Cleator G, Echevarria JM, Falk KI, et al. An international external quality assessment of nucleic acid amplification of herpes simplex virus. J Clin Virol 2003;28(2):175–85]. In addition, genome variability and mutations, which are increasingly recognized for a number of different viruses, can lead to falsely low or negative results. Both clinicians and laboratories must recognize the limitations of PCR, since misleading results may have serious consequences. We present here a case of a rapidly progressive, fatal neurologic illness in a young mother, whose CSF JCV DNA PCR at a reference laboratory was falsely negative. Ultimately, brain biopsy established the diagnosis of progressive multifocal leukoencephalopathy (PML). Repeat PCR testing of the same CSF targeting a different region of the genome yielded a high positive result. PMID:18701345

False contraindications to childhood immunization.

PubMed Central

Kinder, J; Teare, L; Rao, M; Bridgman, G; Kurian, A

1992-01-01

An immunization advisory clinic was set up in mid-Essex in 1988 to provide a referral facility for professionals and parents who were unsure about the eligibility of certain children to receive immunization. This paper describes four typical cases. The history and management of each case are described and the fact that all the children were successfully immunized is highlighted. It is hoped that by sharing the experiences of the immunization advisory clinic with other professional staff, more positive decisions regarding immunizations will be made. PMID:1586553

False contraindications to childhood immunization.

PubMed

Kinder, J; Teare, L; Rao, M; Bridgman, G; Kurian, A

1992-04-01

An immunization advisory clinic was set up in mid-Essex in 1988 to provide a referral facility for professionals and parents who were unsure about the eligibility of certain children to receive immunization. This paper describes four typical cases. The history and management of each case are described and the fact that all the children were successfully immunized is highlighted. It is hoped that by sharing the experiences of the immunization advisory clinic with other professional staff, more positive decisions regarding immunizations will be made.

Competitive binding experiments can reduce the false positive results of affinity-based ultrafiltration-HPLC: A case study for identification of potent xanthine oxidase inhibitors from Perilla frutescens extract.

PubMed

Wang, Zhiqiang; Kwon, Shin Hwa; Hwang, Seung Hwan; Kang, Young-Hee; Lee, Jae-Yong; Lim, Soon Sung

2017-03-24

The purpose of this study was to assess the possibility of using competitive binding experiments with ultrafiltration-HPLC analysis to identify potent xanthine oxidase (XO) inhibitors from the Perilla frutescens extract as an attempt to reduce the number of false positive results. To isolate the enzyme-ligand complex from unbound compounds, the P. frutescens extract was either incubated in the absence of XO, in the presence of XO, or with the active site blocked XO before the ultrafiltration was performed. Allopurinaol was used as the XO active site blocker. The unbound compounds were subjected to HPLC analysis. The degree of total binding (TBD) and degree of specific binding (SBD) of each compound were calculated using the peak areas. TBD represents the binding affinities of compounds from the P. frutescens extract for the XO binding site. SBD represents the XO competitive binding between allopurinol and ligands from the extract samples. Two criteria were applied to select putative targets that could help avoid false positives. These include TBD>30% and SBD>10%. Using that approach, kaempferol-3-O-rutinoside, rosmarinic acid, methyl-rosmarinic acid, apigenin, and 4',5,7-trimethoxyflavone were identified, from total 11 compounds, as potent XO inhibitors. Finally, apigenin, 4',5,7-trimethoxyflavone, and luteolin were XO inhibitors verified through an XO inhibition assay and structural simulation of the complex. These results showed that the newly developed strategy has the advantage that the number of targets identified via ultrafiltration-HPLC can be narrowed from many false positives. However, not all false positives can be eliminated with this approach. Some potent inhibitors might also be excluded with the use of this method. The limitations of this method are also discussed herein. Copyright © 2017 Elsevier B.V. All rights reserved.

Do one-time intracompartmental pressure measurements have a high false-positive rate in diagnosing compartment syndrome?

PubMed

Whitney, Augusta; O'Toole, Robert V; Hui, Emily; Sciadini, Marcus F; Pollak, Andrew N; Manson, Theodore T; Eglseder, W Andrew; Andersen, Romney C; Lebrun, Christopher; Doro, Christopher; Nascone, Jason W

2014-02-01

Intracompartmental pressure measurements are frequently used in the diagnosis of compartment syndrome, particularly in patients with equivocal or limited physical examination findings. Little clinical work has been done to validate the clinical use of intracompartmental pressures or identify associated false-positive rates. We hypothesized that diagnosis of compartment syndrome based on one-time pressure measurements alone is associated with a high false-positive rate. Forty-eight consecutive patients with tibial shaft fractures who were not suspected of having compartment syndrome based on physical examinations were prospectively enrolled. Pressure measurements were obtained in all four compartments at a single point in time immediately after induction of anesthesia using a pressure-monitoring device. Preoperative and intraoperative blood pressure measurements were recorded. The same standardized examination was performed by the attending surgeon preoperatively, postoperatively, and during clinical follow-up for 6 months to assess clinical evidence of acute or late compartment syndrome. No clinical evidence of compartment syndrome was observed postoperatively or during follow-up until 6 months after injury. Using the accepted criteria of delta P of 30 mm Hg from preoperative diastolic blood pressure, 35% of cases (n = 16; 95% confidence interval, 21.5-48.5%) met criteria for compartment syndrome. Raising the threshold to delta P of 20 mm Hg reduced the false-positive rate to 24% (n = 11; 95% confidence interval, 11.1-34.9%). Twenty-two percent (n = 10; 95% confidence interval, 9.5-32.5%) exceeded absolute pressure of 45 mm Hg. A 35% false-positive rate was found for the diagnosis of compartment syndrome in patients with tibial shaft fractures who were not thought to have compartment syndrome by using currently accepted criteria for diagnosis based solely on one-time compartment pressure measurements. Our data suggest that reliance on one-time intracompartmental pressure measurements can overestimate the rate of compartment syndrome and raise concern regarding unnecessary fasciotomies. Diagnostic study, level II.

Estimated number of infants detected and missed by critical congenital heart defect screening.

PubMed

Ailes, Elizabeth C; Gilboa, Suzanne M; Honein, Margaret A; Oster, Matthew E

2015-06-01

In 2011, the US Secretary of Health and Human Services recommended universal screening of newborns for critical congenital heart defects (CCHDs), yet few estimates of the number of infants with CCHDs likely to be detected through universal screening exist. Our objective was to estimate the number of infants with nonsyndromic CCHDs in the United States likely to be detected (true positives) and missed (false negatives) through universal newborn CCHD screening. We developed a simulation model based on estimates of birth prevalence, prenatal diagnosis, late detection, and sensitivity of newborn CCHD screening through pulse oximetry to estimate the number of true-positive and false-negative nonsyndromic cases of the 7 primary and 5 secondary CCHD screening targets identified through screening. We estimated that 875 (95% uncertainty interval [UI]: 705-1060) US infants with nonsyndromic CCHDs, including 470 (95% UI: 360-585) infants with primary CCHD screening targets, will be detected annually through newborn CCHD screening. An additional 880 (UI: 700-1080) false-negative screenings, including 280 (95% UI: 195-385) among primary screening targets, are expected. We estimated that similar numbers of CCHDs would be detected under scenarios comparing "lower" (∼19%) and "higher" (∼41%) than current prenatal detection prevalences. A substantial number of nonsyndromic CCHD cases are likely to be detected through universal CCHD screening; however, an equal number of false-negative screenings, primarily among secondary targets of screening, are likely to occur. Future efforts should document the true impact of CCHD screening in practice. Copyright © 2015 by the American Academy of Pediatrics.

Low hospital referral rates of school scoliosis screening positives in an urban district of mainland China.

PubMed

Guo, Yawen; Jiang, Qingwu; Tanimoto, Tetsuya; Kami, Masahiro; Luo, Chunyan; Leppold, Claire; Nishimura, Koichi; He, Yongpin; Kato, Shigeaki; Ding, Xiaocang

2017-04-01

Significant prevalence rates of adolescent scoliosis in China were suggested in previous studies. However, school screenings for adolescent scoliosis have been suspended due to low rates of positive detection under the past screening system in China. The present study was undertaken to screen for adolescent scoliosis in middle school students under a modern assessment system in a district of Shanghai. We performed a population-based, cross-sectional study of a middle school scoliosis screening program in the Jingan district. In 2015, schoolchildren were initially screened by visual inspection of clinical signs and the forward-bending test. Suspected cases were referred for radiography in hospital for scoliosis diagnosis. A total of 5327 middle school students (grades 6-8) were screened with 520 (9.76%) positives (the positive rates of girls and boys at 15.28% and 4.59%, respectively) and no statistically significant difference among grades. Only 301 positives (57.9%) followed the referral for hospital radiography. There were 102 cases (33.9%) that were diagnosed with scoliosis by radiography criteria (Cobb angle ≥10°) including mild scoliosis (Cobb 10-25) for 94 cases and moderate scoliosis (Cobb 25-40) for 8 cases, and false-positives (Cobb 0) for 39 cases. The putative prevalence rate was estimated as 1.9% from the referred students. Under an accurate and modern assessment system, school screenings can detect scoliosis at a significant rate, but awareness of scoliosis risks is needed for residents in China to take up referrals for hospital diagnosis after school screenings.

Development of a reliable simulation-based test for diagnostic abdominal ultrasound with a pass/fail standard usable for mastery learning.

PubMed

Østergaard, Mia L; Nielsen, Kristina R; Albrecht-Beste, Elisabeth; Konge, Lars; Nielsen, Michael B

2018-01-01

This study aimed to develop a test with validity evidence for abdominal diagnostic ultrasound with a pass/fail-standard to facilitate mastery learning. The simulator had 150 real-life patient abdominal scans of which 15 cases with 44 findings were selected, representing level 1 from The European Federation of Societies for Ultrasound in Medicine and Biology. Four groups of experience levels were constructed: Novices (medical students), trainees (first-year radiology residents), intermediates (third- to fourth-year radiology residents) and advanced (physicians with ultrasound fellowship). Participants were tested in a standardized setup and scored by two blinded reviewers prior to an item analysis. The item analysis excluded 14 diagnoses. Both internal consistency (Cronbach's alpha 0.96) and inter-rater reliability (0.99) were good and there were statistically significant differences (p < 0.001) between all four groups, except the intermediate and advanced groups (p = 1.0). There was a statistically significant correlation between experience and test scores (Pearson's r = 0.82, p < 0.001). The pass/fail-standard failed all novices (no false positives) and passed all advanced (no false negatives). All intermediate participants and six out of 14 trainees passed. We developed a test for diagnostic abdominal ultrasound with solid validity evidence and a pass/fail-standard without any false-positive or false-negative scores. • Ultrasound training can benefit from competency-based education based on reliable tests. • This simulation-based test can differentiate between competency levels of ultrasound examiners. • This test is suitable for competency-based education, e.g. mastery learning. • We provide a pass/fail standard without false-negative or false-positive scores.

Optimization and validation of CEDIA drugs of abuse immunoassay tests in serum on Hitachi 912.

PubMed

Kirschbaum, Katrin M; Musshoff, Frank; Schmithausen, Ricarda; Stockhausen, Sarah; Madea, Burkhard

2011-10-10

Due to sensitive limits of detection of chromatographic methods and low limit values regarding the screening of drugs under the terms of impairment in safe driving (§ 24a StVG, Street Traffic Law in Germany), preliminary immunoassay (IA) tests should be able to detect also low concentrations of legal and illegal drugs in serum in forensic cases. False-negatives should be avoided, the rate of false-positive samples should be low due to cost and time. An optimization of IA cutoff values and a validation of the assay is required for each laboratory. In a retrospective study results for serum samples containing amphetamine, methylenedioxy derivatives, cannabinoids, benzodiazepines, cocaine (metabolites), methadone and opiates obtained with CEDIA drugs of abuse reagents on a Hitachi 912 autoanalyzer were compared with quantitative results of chromatographic methods (gas or liquid chromatography coupled with mass spectrometry (GC/MS or LC/MS)). Firstly sensitivity, specificity, positive and negative predictive values and overall misclassification rates were evaluated by contingency tables and compared to ROC-analyses and Youden-Indices. Secondly ideal cutoffs were statistically calculated on the basis of sensitivity and specificity as decisive statistical criteria with focus on a high sensitivity (low rates of false-negatives), i.e. using the Youden-Index. Immunoassay (IA) and confirmatory results were available for 3014 blood samples. Sensitivity was 90% or more for nearly all analytes: amphetamines (IA cutoff 9.5 ng/ml), methylenedioxy derivatives (IA cutoff 5.5 ng/ml), cannabinoids (IA cutoff 14.5 ng/ml), benzodiazepines (IA cutoff >0 ng/ml). Test of opiates showed a sensitivity of 86% for a IA cutoff value of >0 ng/ml. Values for specificity ranged between 33% (methadone, IA cutoff 10 ng/ml) and 90% (cocaine, IA cutoff 20 ng/ml). Lower cutoff values as recommended by ROC analyses were chosen for most tests to decrease the rate of false-negatives. Analyses enabled the definition of cutoff values with good values for sensitivity. Small rates of false-positives can be accepted in forensic cases. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

False positive acetaminophen concentrations in patients with liver injury.

PubMed

Polson, Julie; Wians, Frank H; Orsulak, Paul; Fuller, Dwain; Murray, Natalie G; Koff, Jonathan M; Khan, Adil I; Balko, Jody A; Hynan, Linda S; Lee, William M

2008-05-01

Acetaminophen toxicity is the most common form of acute liver failure in the U.S. After acetaminophen overdoses, quantitation of plasma acetaminophen can aid in predicting severity of injury. However, recent case reports have suggested that acetaminophen concentrations may be falsely increased in the presence of hyperbilirubinemia. We tested sera obtained from 43 patients with acute liver failure, mostly unrelated to acetaminophen, utilizing 6 different acetaminophen quantitation systems to determine the significance of this effect. In 36 of the 43 samples with bilirubin concentrations ranging from 1.0-61.5 mg/dl no acetaminophen was detectable by gas chromatography-mass spectroscopy. These 36 samples were then utilized to test the performance characteristics of 2 immunoassay and 4 enzymatic-colorimetric methods. Three of four colorimetric methods demonstrated 'detectable' values for acetaminophen in from 4 to 27 of the 36 negative samples, low concentration positive values being observed when serum bilirubin concentrations exceeded 10 mg/dl. By contrast, the 2 immunoassay methods (EMIT, FPIA) were virtually unaffected. The false positive values obtained were, in general, proportional to the quantity of bilirubin in the sample. However, prepared samples of normal human serum with added bilirubin showed a dose-response curve for only one of the 4 colorimetric assays. False positive acetaminophen tests may result when enzymatic-colorimetric assays are used, most commonly with bilirubin concentrations >10 mg/dl, leading to potential clinical errors in this setting. Bilirubin (or possibly other substances in acute liver failure sera) appears to affect the reliable measurement of acetaminophen, particularly with enzymatic-colorimetric assays.

Specificity of the histopathological triad for the diagnosis of toxoplasmic lymphadenitis: polymerase chain reaction study.

PubMed

Lin, M H; Kuo, T T

2001-08-01

Toxoplasmosis is a common cause of lymphadenopathy, but toxoplasmic cysts are not usually found in histological sections used for establishing diagnosis, except on extremely rare occasions. The histopathological triad of florid reactive follicular hyperplasia, clusters of epithelioid histiocytes, and focal sinusoidal distention by monocytoid B cells has been considered to be diagnostic of toxoplasmic lymphadenitis, but the validity of the histopathological triad is based indirectly on serological correlation only. The demonstration of Toxoplasma gondii DNA in lymph nodes displaying the histopathological triad will indicate the validity of the histopathological triad as the criterion for the histopathological diagnosis of toxoplasmic lymphadenitis. We used frozen tissues of 12 lymph nodes with the histopathological triad and tissues of 27 lymph nodes from patients with various other conditions (including 13 cases of follicular lymphoid hyperplasia, FLH; three cases of dermatopathic lymphadenopathy, DPL; two cases of plasmacytosis; two cases of Castleman's disease; two cases of metastatic adenocarcinoma; and five cases of lymphoma) to detect T. gondii DNA by polymerase chain reaction. Ten out of 12 lymph nodes with the triad and six out of 27 lymph nodes without the triad were positive for T. gondii DNA. Thus, the sensitivity of the triad was 62.5% (10/16) and the specificity was 91.3% (21/23). The predictive value of positive tests was 83.3% (10/12) and the predictive value of negative tests was 77.7% (21/27). The six cases positive for T. gondii DNA without the triad were four cases of FLH, one case of DPL, and one case of plasmacytosis. None of the neoplastic diseases was positive. The false positive and negative cases could be due to sampling problems or past T. gondii infection. The results confirm that the histopathological triad is highly specific for the diagnosis of toxoplasmic lymphadenitis and can be used confidently.

Gonorrhoea notifications and nucleic acid amplification testing in a very low-prevalence Australian female population.

PubMed

Chow, Eric P F; Fehler, Glenda; Read, Tim R H; Tabrizi, Sepehr N; Hocking, Jane S; Denham, Ian; Bradshaw, Catriona S; Chen, Marcus Y; Fairley, Christopher K

2015-04-06

To examine whether the rapid increase of gonorrhoea notifications in Victoria, Australia, identified by nucleic acid amplification test (NAAT) is supported by similar changes in diagnoses by culture, which has higher specificity, and to determine the proportion of tests positive among women tested. Retrospective analysis of Medicare reporting of dual NAATs in Victoria, Victorian Department of Health gonorrhoea notifications, and gonorrhoea culture data at the Melbourne Sexual Health Centre (MSHC), among women, 2008 to 2013. Gonorrhoea notifications and testing methods. Gonorrhoea cases identified by NAAT increased from 98 to 343 cases over the study period. Notifications by culture alone decreased from 19 to five cases. The proportion of NAATs positive for gonorrhoea in Victoria was low (0.2%-0.3%) and did not change over time (P for trend, 0.66). Similarly, the proportion of women tested at the MSHC for gonorrhoea who tested positive (0.4%-0.6%) did not change over time (P for trend, 0.70). Of untreated women who had a positive NAAT result for gonorrhoea and were referred to the MSHC, 10/25 were confirmed by culture. The positivity of gonorrhoea in women identified by culture remains stable over time. Using NAAT for gonorrhoea screening in low-prevalence populations will result in many false positives. Positive NAAT results among low-risk women should be regarded as doubtful, and confirmatory cultures should be performed.

A universal mini-vector and an annealing of PCR products (APP)-based cloning strategy for convenient molecular biological manipulations.

PubMed

Liu, Xia; Li, Tuoping; Hart, Darren J; Gao, Song; Wang, Hongling; Gao, Herui; Xu, Shumin; Zhang, Yifeng; Liu, Yifei; An, Yingfeng

2018-03-18

Currently, the most widely used strategies for molecular cloning are sticky-end ligation-based cloning, TA cloning, blunt-end ligation-based cloning and ligase-independent cloning. In this study we have developed a novel mini-vector pANY1 which can simultaneously meet the requirements of all these cloning strategies. In addition, the selection of appropriate restriction digestion sites is difficult in some cases because of the presence of internal sites. In this study, an annealing of PCR products (APP)-based sticky-end cloning strategy was introduced to avoid this issue. Additionally, false positives occur during molecular cloning, which increases the workload of isolating positive clones. The plasmid pANY1 contains a ccdB cassette between multiple cloning sites, which efficiently avoids these false positives. Therefore, this mini-vector should serve as a useful tool with wide applications in biosciences, agriculture, food technologies, etc. Copyright © 2018 Elsevier Inc. All rights reserved.

Robust Detection of Rare Species Using Environmental DNA: The Importance of Primer Specificity

PubMed Central

Wilcox, Taylor M.; McKelvey, Kevin S.; Young, Michael K.; Jane, Stephen F.; Lowe, Winsor H.; Whiteley, Andrew R.; Schwartz, Michael K.

2013-01-01

Environmental DNA (eDNA) is being rapidly adopted as a tool to detect rare animals. Quantitative PCR (qPCR) using probe-based chemistries may represent a particularly powerful tool because of the method’s sensitivity, specificity, and potential to quantify target DNA. However, there has been little work understanding the performance of these assays in the presence of closely related, sympatric taxa. If related species cause any cross-amplification or interference, false positives and negatives may be generated. These errors can be disastrous if false positives lead to overestimate the abundance of an endangered species or if false negatives prevent detection of an invasive species. In this study we test factors that influence the specificity and sensitivity of TaqMan MGB assays using co-occurring, closely related brook trout (Salvelinus fontinalis) and bull trout (S. confluentus) as a case study. We found qPCR to be substantially more sensitive than traditional PCR, with a high probability of detection at concentrations as low as 0.5 target copies/µl. We also found that number and placement of base pair mismatches between the Taqman MGB assay and non-target templates was important to target specificity, and that specificity was most influenced by base pair mismatches in the primers, rather than in the probe. We found that insufficient specificity can result in both false positive and false negative results, particularly in the presence of abundant related species. Our results highlight the utility of qPCR as a highly sensitive eDNA tool, and underscore the importance of careful assay design. PMID:23555689

Robust detection of rare species using environmental DNA: the importance of primer specificity.

PubMed

Wilcox, Taylor M; McKelvey, Kevin S; Young, Michael K; Jane, Stephen F; Lowe, Winsor H; Whiteley, Andrew R; Schwartz, Michael K

2013-01-01

Environmental DNA (eDNA) is being rapidly adopted as a tool to detect rare animals. Quantitative PCR (qPCR) using probe-based chemistries may represent a particularly powerful tool because of the method's sensitivity, specificity, and potential to quantify target DNA. However, there has been little work understanding the performance of these assays in the presence of closely related, sympatric taxa. If related species cause any cross-amplification or interference, false positives and negatives may be generated. These errors can be disastrous if false positives lead to overestimate the abundance of an endangered species or if false negatives prevent detection of an invasive species. In this study we test factors that influence the specificity and sensitivity of TaqMan MGB assays using co-occurring, closely related brook trout (Salvelinus fontinalis) and bull trout (S. confluentus) as a case study. We found qPCR to be substantially more sensitive than traditional PCR, with a high probability of detection at concentrations as low as 0.5 target copies/µl. We also found that number and placement of base pair mismatches between the Taqman MGB assay and non-target templates was important to target specificity, and that specificity was most influenced by base pair mismatches in the primers, rather than in the probe. We found that insufficient specificity can result in both false positive and false negative results, particularly in the presence of abundant related species. Our results highlight the utility of qPCR as a highly sensitive eDNA tool, and underscore the importance of careful assay design.

Inflammatory myofibroblastic tumor of the mesentery associated with high fever and positive Widal test.

PubMed

Chouairy, Camil J; Bechara, Elie A; Gebran, Sleiman J; Ghabril, Ramy H

2008-12-01

Inflammatory myofibroblastic tumor (IMT) is associated in 15-30% of cases with systemic symptomatology, such as prolonged fever, weight loss, elevated erythrocyte sedimentation rate (ESR), anemia, thrombocytosis, and leukocytosis. We report the case of a 4-year-old Lebanese boy who presented with high-grade fever of long duration, and a single (unpaired) positive Widal agglutination test. Blood culture was negative. A diagnosis of typhoid fever was made. An abdominal (mesenteric) IMT was incidentally discovered, 30 days after the fever had appeared. After surgery, the fever disappeared immediately, and the ESR returned to normal. We strongly favor the possibility of a false positive Widal test, due to polyclonal increase in serum immunoglobulins, which often occurs in IMT. We also think that IMT might be a mimicker of typhoid fever, both clinically and serologically. Physicians, especially pediatricians practicing in endemic areas, should probably be aware of this mimicry.

[Pitfalls in the histopathological diagnostics of endometrial carcinoma and its precursors : Clinically relevant differential diagnoses, avoidance of false positive diagnoses].

PubMed

Kommoss, F; Lax, S F

2016-11-01

Making an incorrect histopathological diagnosis of an endometrial lesion may lead to unwanted loss of fertility and therapy-associated morbidity; therefore, endometrial carcinomas need to be correctly typed and differentiated from hyperplastic precursors, benign lesions and artifacts. Typical diagnostic pitfalls are described in this article. Misdiagnosing endometrial lesions can be avoided by paying thorough attention to gross as well as microscopic features and by taking crucial differential diagnoses into consideration. These are, in particular, well-differentiated endometrioid adenocarcinoma of the endometrium versus atypical endometrial hyperplasia, myoinvasive endometrioid adenocarcinoma versus atypical polypoid adenomyoma and endometrioid carcinoma versus serous carcinoma of the endometrium with a predominantly glandular pattern. It is also important to consider the possibility of a false positive diagnosis of atypical endometrial hyperplasia or carcinoma in cases of biopsy-induced artifacts.

Improving computer-aided detection assistance in breast cancer screening by removal of obviously false-positive findings.

PubMed

Mordang, Jan-Jurre; Gubern-Mérida, Albert; Bria, Alessandro; Tortorella, Francesco; den Heeten, Gerard; Karssemeijer, Nico

2017-04-01

Computer-aided detection (CADe) systems for mammography screening still mark many false positives. This can cause radiologists to lose confidence in CADe, especially when many false positives are obviously not suspicious to them. In this study, we focus on obvious false positives generated by microcalcification detection algorithms. We aim at reducing the number of obvious false-positive findings by adding an additional step in the detection method. In this step, a multiclass machine learning method is implemented in which dedicated classifiers learn to recognize the patterns of obvious false-positive subtypes that occur most frequently. The method is compared to a conventional two-class approach, where all false-positive subtypes are grouped together in one class, and to the baseline CADe system without the new false-positive removal step. The methods are evaluated on an independent dataset containing 1,542 screening examinations of which 80 examinations contain malignant microcalcifications. Analysis showed that the multiclass approach yielded a significantly higher sensitivity compared to the other two methods (P < 0.0002). At one obvious false positive per 100 images, the baseline CADe system detected 61% of the malignant examinations, while the systems with the two-class and multiclass false-positive reduction step detected 73% and 83%, respectively. Our study showed that by adding the proposed method to a CADe system, the number of obvious false positives can decrease significantly (P < 0.0002). © 2017 American Association of Physicists in Medicine.

Immunohistochemistry is a reliable screening tool for identification of ALK rearrangement in non-small-cell lung carcinoma and is antibody dependent.

PubMed

Conklin, Chris M J; Craddock, Kenneth J; Have, Cherry; Laskin, Janessa; Couture, Christian; Ionescu, Diana N

2013-01-01

Fluorescence in situ hybridization (FISH) is the standard procedure for the detection of anaplastic lymphoma receptor tyrosine kinase (ALK) rearrangement in non-small-cell lung carcinoma (NSCLC) but is expensive and time consuming. We tested three antibodies to ALK, using various detection systems, and hypothesized that ALK immunohistochemistry (IHC) may represent a cost-effective and efficient means of screening for ALK rearrangement in NSCLC. We screened 377 stage I or II NSCLC cases in a tissue microarray by FISH and IHC (5A4 [Leica Biosystems Newcastle Ltd, Newcastle upon Tyne, UYnited Kingdom] by Nichirei's N-Histofine ALK detection kit [Nichirei Biosciences inc., Tokyo, Japan], 5A4 by Novocastra with ADVANCE [Dako Canada inc., Burlington, Ontario, Canada], D5F3 by Cell Signaling Technology with ADVANCE [Cell Signalling Technologies inc., Danvers, MA], and DAKO clone ALK1 with FLEX [Dako Canada inc., Burlington, Ontario, Canada] and ADVANCE). IHC was scored as 0, 1+, 2+, or 3+. Possibly positive or positive cases were further analyzed by IHC and FISH on whole section. Tissue microarray results were available on 377 cases by IHC and 273 cases by FISH. Eleven cases were positive or possibly positive by either IHC or FISH, and three cases were positive or possibly positive by both methods. Three cases were ALK-positive by FISH on whole section validation. There was no correlation between semiquantitative IHC score (1+, 2+, 3+) and ALK rearrangement by FISH. D5F3 (Cell Signaling by ADVANCE) and 5A4 (Novocastra by ADVANCE) showed the greatest combination of sensitivity (100%) and specificity (87.5% for 5A4 by Novocastra and 75% for D5F3 by Cell Signaling), and produced no false-negative results. IHC is a reliable screening tool for identification of ALK rearrangement in NSCLC and is antibody dependent. D5F3 (Cell Signaling) and 5A4 (Novocastra) can be used with FISH for identification of IHC-positive cases to reduce screening costs.

False biochemical diagnosis of hyperthyroidism in streptavidin-biotin-based immunoassays: the problem of biotin intake and related interferences.

PubMed

Piketty, Marie-Liesse; Polak, Michel; Flechtner, Isabelle; Gonzales-Briceño, Laura; Souberbielle, Jean-Claude

2017-05-01

Immunoassays are now commonly used for hormone measurement, in high throughput analytical platforms. Immunoassays are generally robust to interference. However, endogenous analytical error may occur in some patients; this may be encountered in biotin supplementation or in the presence of anti-streptavidin antibody, in immunoassays involving streptavidin-biotin interaction. In these cases, the interference may induce both false positive and false negative results, and simulate a seemingly coherent hormonal profile. It is to be feared that this type of errors will be more frequently observed. This review underlines the importance of keeping close interactions between biologists and clinicians to be able to correlate the hormonal assay results with the clinical picture.

Detection of breast cancer with full-field digital mammography and computer-aided detection.

PubMed

The, Juliette S; Schilling, Kathy J; Hoffmeister, Jeffrey W; Friedmann, Euvondia; McGinnis, Ryan; Holcomb, Richard G

2009-02-01

The purpose of this study was to evaluate computer-aided detection (CAD) performance with full-field digital mammography (FFDM). CAD (Second Look, version 7.2) was used to evaluate 123 cases of breast cancer detected with FFDM (Senographe DS). Retrospectively, CAD sensitivity was assessed using breast density, mammographic presentation, histopathology results, and lesion size. To determine the case-based false-positive rate, patients with four standard views per case were included in the study group. Eighteen unilateral mammography examinations with nonstandard views were excluded, resulting in a sample of 105 bilateral cases. CAD detected 115 (94%) of 123 cancer cases: six of six (100%) in fatty breasts, 63 of 66 (95%) in breasts containing scattered fibroglandular densities, 43 of 46 (93%) in heterogeneously dense breasts, and three of five (60%) in extremely dense breasts. CAD detected 93% (41/44) of cancers manifesting as calcifications, 92% (57/62) as masses, and 100% (17/17) as mixed masses and calcifications. CAD detected 94% of the invasive ductal carcinomas (n = 63), 100% of the invasive lobular carcinomas (n = 7), 91% of the other invasive carcinomas (n = 11), and 93% of the ductal carcinomas in situ (n = 42). CAD sensitivity for cancers 1-10 mm (n = 55) was 89%; 11-20 mm (n = 37), 97%; 21-30 mm (n = 16), 100%; and larger than 30 mm (n = 15), 93%. The CAD false-positive rate was 2.3 marks per four-image case. CAD with FFDM showed a high sensitivity in identifying cancers manifesting as calcifications and masses. Sensitivity was maintained in cancers with lower mammographic sensitivity, including invasive lobular carcinomas and small neoplasms (1-20 mm). CAD with FFDM should be effective in assisting radiologists with earlier detection of breast cancer. Future studies are needed to assess CAD accuracy in larger populations.

Review of the role of sentinel node biopsy in cutaneous head and neck melanoma.

PubMed

Roy, Jennifer M; Whitfield, Robert J; Gill, P Grantley

2016-05-01

Sentinel node biopsy (SNB) is recommended for selected melanoma patients in many parts of the world. This review examines the evidence surrounding the accuracy and prognostic value of SNB and completion neck dissection in head and neck melanoma. Sentinel nodes were identified in an average of 94.7% of head and neck cases compared with 95.3-100% in all melanoma cases. More false-negative sentinel nodes were found in head and neck cases. A positive sentinel node was associated with both lower disease-free survival (53.4 versus 83.2%) and overall survival (40 versus 84%). We conclude that SNB should be offered to all patients with intermediate and high-risk melanomas in the head and neck area. To date, evidence does not exist to demonstrate the safety of avoiding completion lymph node dissection in sentinel node-positive patients with head and neck melanoma. © 2015 Royal Australasian College of Surgeons.

Specificity of /sup 99m/Tc-pertechnetate in scintigraphic diagnosis of Meckel's diverticulum: review of 100 cases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berquist, T.H.; Nolan, N.G.; Stephens, D.H.

1976-06-01

Numerous reports in the recent literature have questioned the value of abdominal scanning with pertechnetate in the diagnosis of Meckel's diverticulum. In an attempt to evaluate further the specificity of pertechnetate in this condition, the clinical data and scintigrams of 100 patients with suspected Meckel's diverticulum were reviewed. The scintigram correctly identified Meckel's diverticulum before operation in seven of eight patients. One false-negative study occurred in 33 patients who underwent laparotomy. Conditions suggested as possible causes of false-positive studies (hydronephrosis, arteriovenous malformations, and intussusception) were found to give negative scans. (auth)

Sensitivity and Specificity of Interictal EEG-fMRI for Detecting the Ictal Onset Zone at Different Statistical Thresholds

PubMed Central

Tousseyn, Simon; Dupont, Patrick; Goffin, Karolien; Sunaert, Stefan; Van Paesschen, Wim

2014-01-01

There is currently a lack of knowledge about electroencephalography (EEG)-functional magnetic resonance imaging (fMRI) specificity. Our aim was to define sensitivity and specificity of blood oxygen level dependent (BOLD) responses to interictal epileptic spikes during EEG-fMRI for detecting the ictal onset zone (IOZ). We studied 21 refractory focal epilepsy patients who had a well-defined IOZ after a full presurgical evaluation and interictal spikes during EEG-fMRI. Areas of spike-related BOLD changes overlapping the IOZ in patients were considered as true positives; if no overlap was found, they were treated as false-negatives. Matched healthy case-controls had undergone similar EEG-fMRI in order to determine true-negative and false-positive fractions. The spike-related regressor of the patient was used in the design matrix of the healthy case-control. Suprathreshold BOLD changes in the brain of controls were considered as false positives, absence of these changes as true negatives. Sensitivity and specificity were calculated for different statistical thresholds at the voxel level combined with different cluster size thresholds and represented in receiver operating characteristic (ROC)-curves. Additionally, we calculated the ROC-curves based on the cluster containing the maximal significant activation. We achieved a combination of 100% specificity and 62% sensitivity, using a Z-threshold in the interval 3.4–3.5 and cluster size threshold of 350 voxels. We could obtain higher sensitivity at the expense of specificity. Similar performance was found when using the cluster containing the maximal significant activation. Our data provide a guideline for different EEG-fMRI settings with their respective sensitivity and specificity for detecting the IOZ. The unique cluster containing the maximal significant BOLD activation was a sensitive and specific marker of the IOZ. PMID:25101049

Deep venous thrombophlebitis: detection with 4-hour versus 24-hour platelet scintigraphy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seabold, J.E.; Conrad, G.R.; Ponto, J.A.

Thirty-one nonheparinized patients with suspected deep venous thrombophlebitis (DVT) underwent contrast venography and indium-111 platelet scintigraphy (In-111 PS). Venography permitted identification of acute DVT in 12 of 31 cases (39%). One additional patient was considered to have acute DVT despite nonconclusive venography results. In-111 PS results were positive at 4 hours in nine of 13 cases (69%) and at 24 hours in 12 of 13 cases (92%). Two of four patients with false-negative 4-hour In-111 PS studies had received warfarin. Thus, the sensitivity of 4-hour In-111 PS in patients not receiving anticoagulants was 82%. Venography results were negative for acutemore » DVT in 18 cases, and 4-hour In-111 PS studies were negative or equivocal in each. In-111 PS is an alternative to contrast venography for detecting acute DVT. If 4-hour In-111 PS results are positive, anticoagulation can be initiated. Delayed images are necessary if the 4-hour images are negative or equivocal.« less

Statistical approaches to account for false-positive errors in environmental DNA samples.

PubMed

Lahoz-Monfort, José J; Guillera-Arroita, Gurutzeta; Tingley, Reid

2016-05-01

Environmental DNA (eDNA) sampling is prone to both false-positive and false-negative errors. We review statistical methods to account for such errors in the analysis of eDNA data and use simulations to compare the performance of different modelling approaches. Our simulations illustrate that even low false-positive rates can produce biased estimates of occupancy and detectability. We further show that removing or classifying single PCR detections in an ad hoc manner under the suspicion that such records represent false positives, as sometimes advocated in the eDNA literature, also results in biased estimation of occupancy, detectability and false-positive rates. We advocate alternative approaches to account for false-positive errors that rely on prior information, or the collection of ancillary detection data at a subset of sites using a sampling method that is not prone to false-positive errors. We illustrate the advantages of these approaches over ad hoc classifications of detections and provide practical advice and code for fitting these models in maximum likelihood and Bayesian frameworks. Given the severe bias induced by false-negative and false-positive errors, the methods presented here should be more routinely adopted in eDNA studies. © 2015 John Wiley & Sons Ltd.

Hepatitis C Virus Core Mutations Associated with False-Negative Serological Results for Genotype 3a Core Antigen

PubMed Central

Dunford, Linda; Freitas, Ines; Holder, Paul; Nguyen, Lan Anh; O'Gorman, Joanne; Connell, Jeff; Carr, Michael; Hall, William; De Gascun, Cillian

2015-01-01

Genetic characterization of the genotype 3a (GT3a) hepatitis C virus (HCV) core region from HCV core antigen (HCVcAg)-negative/RNA-positive cases and HCVcAg-positive/RNA-positive controls identified significant associations between the substitutions A48T and T49A/P and failure to detect HCVcAg (P < 0.05). Polymorphisms at residues 48 and 49 in the core protein are present across all major epidemic and endemic GTs. These findings have implications for HCV diagnosis, particularly in low-income regions in which GT3a HCV is endemic. PMID:25994168

Hypertensive emergency masquerading as phaeochromocytoma: a report of two cases.

PubMed

Hulkower, Raphael; Gubbi, Sriram; Meholli, Mimoza; Schubart, Ulrich

2017-08-07

We report two cases of patients who were hospitalised for hypertensive emergency. In both cases, laboratory testing during admission revealed elevated normetanephrines in the range of 4-5 times the upper limit of normal using liquid chromatography with mass spectrometry. Imaging studies did not localise any phaeochromocytoma or paraganglioma (PPGL). Repeat biochemical testing after discharge was within normal limits in both cases. These observations suggest that hypertensive emergency should be recognised as a potential cause of 'false-positive' laboratory findings in the diagnostic assessment for PPGL. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Differential diagnosis of solitary pulmonary nodules based on 99mTc-EDDA/HYNIC-TOC scintigraphy: the effect of tumour size on the optimal method of image assessment.

PubMed

Płachcińska, Anna; Mikołajczak, Renata; Kozak, Józef; Rzeszutek, Katarzyna; Kuśmierek, Jacek

2006-09-01

The aim of the study was to determine an optimal method for the evaluation of scintigrams obtained with (99m)Tc-EDDA/HYNIC-TOC for the purpose of differential diagnosis of solitary pulmonary nodules (SPNs) and to assess the diagnostic value of the method. Eighty-five patients (48 males and 37 females, mean age 57 years, range 34-78 years) were enrolled in the study. Patients underwent (99m)Tc-EDDA/HYNIC-TOC scintigraphy for the purpose of differential diagnosis of SPNs (size between 1 and 4 cm). Images of all patients were evaluated visually in a prospective manner. Positive scintigraphic results were found in 37 out of 40 (93%) patients with malignant SPNs including 34 out of 35 (97%) patients with primary lung carcinoma. Two remaining false negative cases turned out to be metastatic lesions of malignant melanoma and leiomyosarcoma. Among 45 benign tumours, negative results were obtained in 31 cases (69%) and positive results in 14. The accuracy of the method was 80%. Analysis of the results of the visual assessment of scintigrams revealed a significantly higher frequency of false positive results among larger nodules (diameter at least 1.4 cm). Uptake of the tracer in those nodules was therefore assessed semi-quantitatively (using the tumour-to-background ratio), in expectation of an improvement in the low specificity of the visual method. The semi-quantitative assessment reduced the total number of false positive results in a subgroup of larger nodules from 13 to six, while preserving the high sensitivity of the method. The combination of visual analysis (for lesions smaller than 1.4 cm in diameter) and semi-quantitative assessment (for larger lesions) provided a high sensitivity of the method and significantly improved its specificity (84%) and accuracy (88%) in comparison with visual analysis (p<0.05).

Misalignment of disposable pulse oximeter probes results in false saturation readings that influence anesthetic management.

PubMed

Guan, Zhonghui; Baker, Keith; Sandberg, Warren S

2009-11-01

We report a small case series in which misaligned disposable pulse oximeter sensors gave falsely low saturation readings. In each instance, the sensor performed well during preinduction oxygen administration and the early part of the case, most notably by producing a plethysmographic trace rated as high quality by the oximeter software. The reported pulse oximeter oxygen saturation eventually decreased to concerning levels in each instance, but the anesthesiologists, relying on the reported high-quality signal, initially sought other causes for apparent hypoxia. They undertook maneuvers and diagnostic procedures later deemed unnecessary. When the malpositioned sensors were discovered and repositioned, the apparent hypoxia was quickly relieved in each case. We then undertook a survey of disposable oximeter sensors as patients entered the recovery room, and discovered malposition of more than 1 cm in approximately 20% of all sensors, without apparent consequence. We conclude that the technology is quite robust, but that the diagnosis of apparent hypoxia should include a quick check of oximeter position early on.

Prenatal diagnosis of congenital toxoplasmosis: comparative value of fetal blood and amniotic fluid using serological techniques and cultures.

PubMed

Fricker-Hidalgo, H; Pelloux, H; Muet, F; Racinet, C; Bost, M; Goullier-Fleuret, A; Ambroise-Thomas, P

1997-09-01

The prenatal diagnosis of congenital toxoplasmosis is mainly based on biological tests performed on fetal blood and amniotic fluid. We studied the performance of neonatal diagnosis procedures and the results of fetal blood and amniotic fluid analysis. Of 127 women who contracted toxoplasmosis and underwent prenatal diagnosis, the postnatal serological follow-up was long enough to definitively diagnose congenital toxoplasmosis in 19 cases and to exclude it in 27 cases. Prenatal diagnosis allowed the detection of 94.7 per cent (18/19) of the infected fetuses. The sensitivities of tests in amniotic fluid and fetal blood were equivalent, 88.2 per cent (15/17) and 87.5 per cent (14/16), respectively. In fetal blood, biological techniques were positive in 12/16 cases and in 2/16 cases, serological tests were the only positive sign. The specificities of tests in amniotic fluid and fetal blood were respectively 100 per cent (23/23) and 86.3 per cent (19/22) (three false-positive serological results). These results, added to the lower morbidity of amniocentesis compared with cordocentesis, might lead to cordocentesis being abandoned in the prenatal diagnosis of congenital toxoplasmosis.

Neonatal respiratory distress syndrome: Chest X-ray or lung ultrasound? A systematic review

PubMed Central

Culpan, Anne-Marie; Watts, Catriona; Munyombwe, Theresa; Wolstenhulme, Stephen

2017-01-01

Background and aim Neonatal respiratory distress syndrome is a leading cause of morbidity in preterm new-born babies (<37 weeks gestation age). The current diagnostic reference standard includes clinical testing and chest radiography with associated exposure to ionising radiation. The aim of this review was to compare the diagnostic accuracy of lung ultrasound against the reference standard in symptomatic neonates of ≤42 weeks gestation age. Methods A systematic search of literature published between 1990 and 2016 identified 803 potentially relevant studies. Six studies met the review inclusion criteria and were retrieved for analysis. Quality assessment was performed before data extraction and meta-analysis. Results Four prospective cohort studies and two case control studies included 480 neonates. All studies were of moderate methodological quality although heterogeneity was evident across the studies. The pooled sensitivity and specificity of lung ultrasound were 97% (95% confidence interval [CI] 94–99%) and 91% (CI: 86–95%) respectively. False positive diagnoses were made in 16 cases due to pneumonia (n = 8), transient tachypnoea (n = 3), pneumothorax (n = 1) and meconium aspiration syndrome (n = 1); the diagnoses of the remaining three false positive results were not specified. False negatives diagnoses occurred in nine cases, only two were specified as air-leak syndromes. Conclusions Lung ultrasound was highly sensitive for the detection of neonatal respiratory distress syndrome although there is potential to miss co-morbid air-leak syndromes. Further research into lung ultrasound diagnostic accuracy for neonatal air-leak syndrome and economic modelling for service integration is required before lung ultrasound can replace chest radiography as the imaging component of the reference standard. PMID:28567102

Impact of sentinel lymph node biopsy on immediate breast reconstruction after mastectomy.

PubMed

Wood, Benjamin C; David, Lisa R; Defranzo, Anthony J; Stewart, John H; Shen, Perry; Geisinger, Kim R; Marks, Malcolm W; Levine, Edward A

2009-07-01

Traditionally, sentinel lymph node biopsy (SLNB) is performed at the time of mastectomy and reconstruction. However, several groups have advocated SLNB as a separate outpatient procedure before mastectomy, when immediate reconstruction is planned, to allow for complete pathologic evaluation. The purpose of this study was to determine the impact of intraoperative analysis of SLNB on the reconstructive plan when performed at the same time as definitive surgery. A retrospective review was conducted of all mastectomy cases performed at a single institution between September 1998 and November 2007. Of the 747 mastectomy cases reviewed, SLNB was conducted in 344 cases, and there was immediate breast reconstruction in 193 of those cases. There were 27 (7.8%) false negative and three (0.9%) false positive intraoperative analysis of SLNB. Touch preparation analysis from the SLNB changed the reconstructive plan in four (2.1%) cases. In our experience, SLNB can be performed at the time of mastectomy with minimal impact on the reconstructive plan. A staged approach incurs significant additional expense, increases the delay in initiation of systemic therapy and the propensity of procedure-related morbidity; therefore, SLNB should not be performed as a separate procedure before definitive surgery with immediate breast reconstruction.

A Closer Look at Self-Reported Suicide Attempts: False Positives and False Negatives

ERIC Educational Resources Information Center

Ploderl, Martin; Kralovec, Karl; Yazdi, Kurosch; Fartacek, Reinhold

2011-01-01

The validity of self-reported suicide attempt information is undermined by false positives (e.g., incidences without intent to die), or by unreported suicide attempts, referred to as false negatives. In a sample of 1,385 Austrian adults, we explored the occurrence of false positives and false negatives with detailed, probing questions. Removing…

Prevention. How much harm? How much benefit? 3. Physical, psychological and social harm.

PubMed Central

Marshall, K G

1996-01-01

Harm caused by preventive programs may be physical, psychological, social or, if informed consent has not been obtained, ethical. Adverse effects of preventive screening programs may occur at any of the three levels of the "screening cascade", the screening procedure itself, the investigation of abnormal results of screening tests or the treatment of detected abnormalities or diseases. The greatest harm occurs at the second and third levels. Examples of procedures that may cause physical harm are venipuncture, mammography, colonoscopy, breast biopsy, transrectal ultrasonography, prostate biopsy, weight-reducing and cholesterol-lowering diets and radical prostatectomy. The psychological and social harm of preventive programs involves anticipated discomfort or perception of adverse effects of preventive interventions; unpleasant interactions with health care workers, time required for preventive programs, excessive overall awareness of health, anxiety over the results of a screening test implications of a positive screening test, consequences of being labelled as "sick" or "at risk," psychopathologic effects induced directly by preventive programs and, in the case of a false-negative test result, false assurance of disease-free status. Since the positive predictive value of screening tests in the general population is always low, most abnormal test results are "false-positive," these engender a great deal of psychological discuss among patients. PMID:8800074

Bone scintigraphy for neonatal osteomyelitis: simulation by extravasation of intravenous calcium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balsam, D.; Goldfarb, C.R.; Stringer, B.

Intravenously administered calcium gluconate has become increasingly popular in the treatment of neonatal tetany. Occasionally, extravasation results in cellulitis, leading to a clinical diagnosis of superimposed osteomyelitis. Osseous scintigraphy, as the accepted modality in the early detection of osteomyelitis, would tend to be used in this circumstance. This case illustrates a false-positive result, probably due to soft-tissue calcification.

The Diagnostic Value of Routine Contrast Esophagram in Anastomotic Leaks After Esophagectomy.

PubMed

Hu, Zhongwu; Wang, Xiaowe; An, Xush; Li, Wenjin; Feng, Yun; You, Zhenbing

2017-08-01

Routine contrast esophagram has been shown to be increasingly limited in diagnosing anastomotic leaks after esophagectomy. Patients undergoing esophagectomy from 2013 to 2014 at Huai'an First Peoples' Hospital were identified. We retrospectively analyzed patients who underwent routine contrast esophagram on postoperative day 7 (range 6-10) to preclude anastomotic leaks after esophagectomy. In 846 patients who underwent esophagectomy, a cervical anastomosis was performed in 286 patients and an intrathoracic anastomosis in 560 patients. There were 57 (6.73%) cases with anastomotic leaks, including cervical leaks in 36 and intrathoracic leaks in 21 patients. In the cervical anastomotic leak patients, 13 were diagnosed by early local clinical symptoms and 23 underwent routine contrast esophagram. There were 7 (30.4%) true-positive, 11 (47.8%) false-negative, and five (21.8%) equivocal cases. In the intrathoracic anastomotic leak patients, four (19%) were diagnosed by clinical symptoms, 16 (76.2%) were true positives, and one (4.8%) was a false negative. Aspiration occurred in five patients with cervical anastomoses and in eight patients with intrathoracic anastomoses; aspiration pneumonitis did not occur in these cases. Gastrografin and barium are safe contrast agents to use in post-esophagectomy contrast esophagram. Because of the low sensitivity in detecting cervical anastomotic leaks, routine contrast esophagram is not advised. For patients with intrathoracic anastomoses, it is still an effective method for detecting anastomotic leaks.

Burden of major diarrheagenic protozoan parasitic co-infection among amoebic dysentery cases from North East India: a case report.

PubMed

Nath, Joyobrato; Hussain, Gulzar; Singha, Baby; Paul, Jaishree; Ghosh, Sankar Kumar

2015-09-01

Intestinal diarrheagenic polyparasitic infections are among the major public health concerns in developing countries. Here we examined stool specimens by microscopy, DNA dot blot and polymerase chain reaction (PCR) to evaluate the co-infection of four principal protozoans among amoebic dysentery cases from Northeast Indian population. The multiplex PCR confirmed Entamoeba histolytica (8.1%), Entamoeba dispar (4.8%) and mixed infection of both the parasites (3.4%) in 68 of 356 stool specimens that were positive in microscopy and/or HMe probe based DNA dot blot screening. The prevailing parasite that co-exists with E. histolytica was Giardia duodenalis (34.1%), followed by Enterocytozoon bieneusi (22.0%), Cryptosporidium parvum (14.6%) and Cyclospora cayetanensis (7.3%, P = 0.017). Symptomatic participants (odds ratio (OR) = 4.07; 95% confidence interval (CI) = 1.06, 15.68; P = 0.041), monsoon season (OR = 7.47; 95% CI = 1.40, 39.84; P = 0.046) and participants with family history of parasitic infection (OR = 4.50; 95% CI = 1.16, 17.51; P = 0.030) have significant association with overall co-infection rate. According to molecular consensus, comprehensive microscopy yielded 3.4% (12/356) false-negative and 7.6% (27/356) false-positive outcome, suggesting an improved broad-spectrum PCR-based diagnostic is required to scale down the poor sensitivity and specificity as well as implementation of integrated control strategy.

Chronic bacterial osteomyelitis: prospective comparison of (18)F-FDG imaging with a dual-head coincidence camera and (111)In-labelled autologous leucocyte scintigraphy.

PubMed

Meller, J; Köster, G; Liersch, T; Siefker, U; Lehmann, K; Meyer, I; Schreiber, K; Altenvoerde, G; Becker, W

2002-01-01

Indium-111-labelled white blood cells ((111)In-WBCs) are currently considered the tracer of choice in the diagnostic work-up of suspected active chronic osteomyelitis (COM). Previous studies in a limited number of patients, performed with dedicated PET systems, have shown that [(18)F]2'-deoxy-2-fluoro- D-glucose (FDG) imaging may offer at least similar diagnostic accuracy. The aim of this prospective study was to compare FDG imaging with a dual-head coincidence camera (DHCC) and (111)In-WBC imaging in patients with suspected COM. Thirty consecutive non-diabetic patients with possible COM underwent combined skeletal scintigraphy (30/30 patients), (111)In-WBC imaging (28/30 patients) and FDG-PET with a DHCC (30/30 patients). During diagnostic work-up, COM was proven in 11/36 regions of suspected skeletal infection and subsequently excluded in 25/36 regions. In addition, soft tissue infection was present in five patients and septic arthritis in three. (111)In-WBC imaging in 28 patients was true positive in 2/11 regions with proven COM and true negative in 21/23 regions without further evidence of COM. False-positive results occurred in two regions and false-negative results in nine regions suspected for COM. Most of the false-negative results (7/9) occurred in the central skeleton. If the analysis was restricted to the 18 regions with available histology ( n=17) or culture ( n=1), (111)In-WBC imaging was true positive in 2/18 regions, true negative in 8/18 regions, false negative in 7/18 regions and false positive in 1/18 regions. FDG-DHCC imaging was true positive in 11/11 regions with proven COM and true negative in 23/25 regions without further evidence of COM. False-positive results occurred in two regions. If the analysis was restricted to the 19 regions with available histology ( n=18) or culture ( n=1), FDG-DHCC imaging was true positive in 9/9 regions with proven COM and true negative in 10/10 regions without further evidence of COM. It is concluded that FDG-DHCC imaging is superior to (111)In-WBC scintigraphy in the diagnosis of COM in the central skeleton and therefore should be considered the method of choice for this indication. This seems to hold true for peripheral lesions as well, but in our series the number of cases with proven infection was too small to permit a final conclusion.

"False Positive" Claims of Near-Death Experiences and "False Negative" Denials of Near-Death Experiences

ERIC Educational Resources Information Center

Greyson, Bruce

2005-01-01

Some persons who claim to have had near-death experiences (NDEs) fail research criteria for having had NDEs ("false positives"); others who deny having had NDEs do meet research criteria for having had NDEs ("false negatives"). The author evaluated false positive claims and false negative denials in an organization that promotes near-death…

Peripheral Synucleinopathy in Early Parkinson’s Disease: Submandibular Gland Needle Biopsy Findings

PubMed Central

Adler, Charles H.; Dugger, Brittany N.; Hentz, Joseph G.; Hinni, Michael L.; Lott, David G.; Driver-Dunckley, Erika; Mehta, Shyamal; Serrano, Geidy; Sue, Lucia I.; Duffy, Amy; Intorcia, Anthony; Filon, Jessica; Pullen, Joel; Walker, Douglas G.; Beach, Thomas G.

2015-01-01

Background Finding a peripheral tissue biopsy site to diagnose early Parkinson’s disease would be of value for clinical care, biomarker validation, and as research enrollment criteria. While autopsy and advanced Parkinson’s disease studies suggest submandibular gland is an important biopsy site, there are no studies in early Parkinson’s disease. Objectives Determine whether needle biopsy of the submandibular gland reveals Lewy type α-synucleinopathy in early Parkinson’s disease. Methods Twenty-five early Parkinson’s disease (duration < 5 years) and 10 controls underwent transcutaneous needle core biopsies of the submandibular gland. Tissue was stained for phosphorylated α-synuclein, reviewed blind to clinical diagnosis, and only nerve element staining was considered positive. Results Mean (Standard Deviation) age 69.5 (8.3) for Parkinson’s disease group, 64.8 (8.0) years for controls, and disease duration 2.6 (1.1) years. Six Parkinson’s disease and one control subject had inadequate glandular tissue. Positive staining was found in 14/19 (74%) Parkinson’s disease and 2/9 (22%) control subjects. Parkinson’s disease positive and negative cases did not differ clinically. Adverse events (mainly swelling and bruising) were common (77% of cases), but were minor and transient. Conclusions Submandibular gland needle biopsies identified phosphorylated α-synuclein staining in 74% of early Parkinson’s disease subjects. False positives may be true false positives or may represent prodromal Parkinson’s disease. If confirmed in larger studies with eventual autopsy confirmation, the potential value of submandibular gland biopsies for early Parkinson’s disease may be to aid in clinical trial inclusion/exclusion and eventually serve as a gold standard for biomarker studies short of autopsy confirmation. PMID:26799362

Risk of breast cancer after false-positive results in mammographic screening.

PubMed

Román, Marta; Castells, Xavier; Hofvind, Solveig; von Euler-Chelpin, My

2016-06-01

Women with false-positive results are commonly referred back to routine screening. Questions remain regarding their long-term outcome of breast cancer. We assessed the risk of screen-detected breast cancer in women with false-positive results. We conducted a joint analysis using individual level data from the population-based screening programs in Copenhagen and Funen in Denmark, Norway, and Spain. Overall, 150,383 screened women from Denmark (1991-2008), 612,138 from Norway (1996-2010), and 1,172,572 from Spain (1990-2006) were included. Poisson regression was used to estimate the relative risk (RR) of screen-detected cancer for women with false-positive versus negative results. We analyzed information from 1,935,093 women 50-69 years who underwent 6,094,515 screening exams. During an average 5.8 years of follow-up, 230,609 (11.9%) women received a false-positive result and 27,849 (1.4%) were diagnosed with screen-detected cancer. The adjusted RR of screen-detected cancer after a false-positive result was 2.01 (95% CI: 1.93-2.09). Women who tested false-positive at first screen had a RR of 1.86 (95% CI: 1.77-1.96), whereas those who tested false-positive at third screening had a RR of 2.42 (95% CI: 2.21-2.64). The RR of breast cancer at the screening test after the false-positive result was 3.95 (95% CI: 3.71-4.21), whereas it decreased to 1.25 (95% CI: 1.17-1.34) three or more screens after the false-positive result. Women with false-positive results had a twofold risk of screen-detected breast cancer compared to women with negative tests. The risk remained significantly higher three or more screens after the false-positive result. The increased risk should be considered when discussing stratified screening strategies. © 2016 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

US women's attitudes to false positive mammography results and detection of ductal carcinoma in situ: cross sectional survey

PubMed Central

Schwartz, Lisa M; Woloshin, Steven; Sox, Harold C; Fischhoff, Baruch; Welch, H Gilbert

2000-01-01

Objective To determine women's attitudes to and knowledge of both false positive mammography results and the detection of ductal carcinoma in situ after screening mammography. Design Cross sectional survey. Setting United States. Participants 479 women aged 18-97 years who did not report a history of breast cancer. Main outcome measures Attitudes to and knowledge of false positive results and the detection of ductal carcinoma in situ after screening mammography. Results Women were aware that false positive results do occur. Their median estimate of the false positive rate for 10 years of annual screening was 20% (25th percentile estimate, 10%; 75th percentile estimate, 45%). The women were highly tolerant of false positives: 63% thought that 500 or more false positives per life saved was reasonable and 37% would tolerate 10 000 or more. Women who had had a false positive result (n=76) expressed the same high tolerance: 39% would tolerate 10 000 or more false positives. 62% of women did not want to take false positive results into account when deciding about screening. Only 8% of women thought that mammography could harm a woman without breast cancer, and 94% doubted the possibility of non-progressive breast cancers. Few had heard about ductal carcinoma in situ, a cancer that may not progress, but when informed, 60% of women wanted to take into account the possibility of it being detected when deciding about screening. Conclusions Women are aware of false positives and seem to view them as an acceptable consequence of screening mammography. In contrast, most women are unaware that screening can detect cancers that may never progress but feel that such information would be relevant. Education should perhaps focus less on false positives and more on the less familiar outcome of detection of ductal carcinoma in situ. PMID:10856064

Serum Free Light Chain Assay and κ/λ Ratio Performance in Patients Without Monoclonal Gammopathies:  High False-Positive Rate.

PubMed

Singh, Gurmukh

2016-08-01

Serum free light chain assay is a recommended screening test for monoclonal gammopathies. Anecdotal observations indicated a high rate of false-positive abnormal κ/λ ratios. This study was undertaken to ascertain the magnitude of the false-positive rate and factors contributing to the error rate. Results of serum protein electrophoresis, serum free light chains, and related tests, usually done for investigation of suspected monoclonal gammopathy, were reviewed retrospectively for 270 patients and 297 observations. Using the conventional κ/λ ratio, 36.4% of the ratios were abnormal, in the absence of monoclonal gammopathy. When the renal κ/λ ratio was used, the rate of abnormal κ/λ ratios was 30.1%. In patients with a γ-globulin concentration of 1.6 g/dL or more, the usual κ/λ ratio was abnormal in 54.8% of the patients. Urine protein electrophoresis was used in 53 (19.6%) instances, whereas bone marrow examination was done in 65 (24.1%) cases. Usual κ/λ ratio was abnormal in 36.4% of the observations in patients without evidence of monoclonal gammopathy, and an abnormal κ/λ ratio should not be used as the sole indicator for diagnosis of neoplastic proliferation of the lympho-plasmacytic system. Hypergammaglobulinemia is associated with a higher rate of false-positive abnormal κ/λ ratios. Examination of urine for monoclonal immunoglobulins may be underused, and recommendations by some to use serum free light chain assay in place of, rather than as an adjunct to, urine electrophoresis are not warranted. © American Society for Clinical Pathology, 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

[A case of systemic lupus erythematosus discovered from left heart failure due to lupus induced mitral regurgitation].

PubMed

Ueno, K; Fujimoto, S; Fujimoto, T; Nakano, H; Nakajima, T; Yamano, S; Shiiki, H; Hashimoto, T; Imoto, K; Miyagawa, S; Dohi, K

1999-10-01

A 50-year-old female was admitted to a local hospital because of dyspnea, and diagnosed as having left heart failure secondary to mitral regurgitation. After the improvement of congestive heart failure, polyarthralgia, fever, and positive anti-nuclear antibody were pointed out. She was referred to our hospital for the further evaluation. Serological test showed anti-double stranded DNA antibodies, anti-SS-A antibodies, anti-beta 2-GPI antibodies and biological false positive for syphilis. The diagnosis of SLE has been made from the clinical signs and the serology. Therefore mitral valvular lesion of this patient was considered to be one of the symptoms of SLE. We reported a rare case in which left heart failure was a initial clinical manifestation of SLE.

Detecting differentially expressed genes in heterogeneous diseases using half Student's t-test.

PubMed

Hsu, Chun-Lun; Lee, Wen-Chung

2010-12-01

Microarray technology provides information about hundreds and thousands of gene-expression data in a single experiment. To search for disease-related genes, researchers test for those genes that are differentially expressed between the case subjects and the control subjects. The authors propose a new test, the 'half Student's t-test', specifically for detecting differentially expressed genes in heterogeneous diseases. Monte-Carlo simulation shows that the test maintains the nominal α level quite well for both normal and non-normal distributions. Power of the half Student's t is higher than that of the conventional 'pooled' Student's t when there is heterogeneity in the disease under study. The power gain by using the half Student's t can reach ∼10% when the standard deviation of the case group is 50% larger than that of the control group. Application to a colon cancer data reveals that when the false discovery rate (FDR) is controlled at 0.05, the half Student's t can detect 344 differentially expressed genes, whereas the pooled Student's t can detect only 65 genes. Or alternatively, if only 50 genes are to be selected, the FDR for the pooled Student's t has to be set at 0.0320 (false positive rate of ∼3%), but for the half Student's t, it can be at as low as 0.0001 (false positive rate of about one per ten thousands). The half Student's t-test is to be recommended for the detection of differentially expressed genes in heterogeneous diseases.

Texture-based CAD improves diagnosis for low-dose CT colonography

NASA Astrophysics Data System (ADS)

Liang, Zhengrong; Cohen, Harris; Posniak, Erica; Fiore, Eddie; Wang, Zigang; Li, Bin; Andersen, Joseph; Harrington, Donald

2008-03-01

Computed tomography (CT)-based virtual colonoscopy or CT colonography (CTC) currently utilizes oral contrast solutions to tag the colonic fluid and possibly residual stool for differentiation from the colon wall and polyps. The enhanced image density of the tagged colonic materials causes a significant partial volume (PV) effect into the colon wall as well as the lumen space (filled with air or CO II). The PV effect on the colon wall can "bury" polyps of size as large as 5mm by increasing their image densities to a noticeable level, resulting in false negatives. It can also create false positives when PV effect goes into the lumen space. We have been modeling the PV effect for mixture-based image segmentation and developing text-based computer-aided detection of polyp (CADpolyp) by utilizing the PV mixture-based image segmentation. This work presents some preliminary results of developing and applying texture-based CADpolyp technique to low-dose CTC studies. A total of 114 studies of asymptomatic patients older than 50, who underwent CTC and then optical colonoscopy (OC) on the same day, were selected from a database, which was accumulated in the past decade and contains various bowel preparations and CT scanning protocols. The participating radiologists found ten polyps of greater than 5 mm from a total of 16 OC proved polyps, i.e., a detection sensitivity of 63%. They scored 23 false positives from the database, i.e., a 20% false positive rate. Approximately 70% of the datasets were marked as imperfect bowel cleansing and/or presence of image artifacts. The impact of imperfect bowel cleansing and image artifacts on VC performance is significant. The texture-based CADpolyp detected all the polyps with an average of 2.68 false positives per patient. This indicates that texture-based CADpolyp can improve the CTC performance in the cases of imperfect cleansed bowels and presence of image artifacts.

Application of a novel prenatal vertical cranial biometric measurement can improve accuracy of microcephaly diagnosis in utero.

PubMed

Leibovitz, Z; Shiran, C; Haratz, K; Tamarkin, M; Gindes, L; Schreiber, L; Malinger, G; Ben-Sira, L; Lev, D; Shapiro, I; Bakry, H; Weizman, B; Zreik, A; Kidron, D; Egenburg, S; Arad, A; Lerman-Sagie, T

2016-05-01

To construct a reference range for a new vertical measurement of the fetal head and to assess whether its combination with fetal head circumference (HC) can prevent the misdiagnosis of microcephaly in fetuses with an acrocephalic-like head deformation. A new vertical cranial biometric measurement was defined: the foramen magnum-to-cranium distance (FCD), measured between the foramen magnum and the upper inner cranial border along the posterior wall of the brainstem. The measurement was performed in a precise mid-sagittal plane using a three-dimensional multiplanar display of a sagittally acquired sonographic volume of the fetal head. The normal reference range was developed by measuring 396 healthy fetuses of low-risk singleton pregnancies between 15 and 40 gestational weeks. This reference was applied to 25 fetuses with microcephaly diagnosed prenatally (Fmic) based on HC ≥ 3 SD below the mean for gestational age. We determined an optimal FCD cut-off for combination with HC to detect all cases found with microcephaly at birth (micB), while excluding the fetuses with normal head circumference at birth (NHCB), who were described postnatally as having an acrocephalic-like cranial deformation. In the healthy singleton fetuses, FCD increased with gestational age, with a quadratic equation providing an optimal fit to the data (adjusted R(2) = 0.934). The measurement could be assessed in 95.2% of cases. Of the 25 cases diagnosed with Fmic prenatally, on the basis of HC alone, 14 were micB and 11 were NHCB. We observed FCD below the mean - 2SD for gestational age in all 14 micB cases, but in only four of the 11 NHCB cases (P < 0.003). An acrocephalic-like cranial deformation was described at birth in five of the seven NHCB cases with normal FCD. The mean ± SD FCD Z-score of the micB cases was significantly lower (P < 0.001) than that of the false-positive ones: -3.85 ± 0.96 SD and -1.59 ± 1.45 SD, respectively. Based on HC measurement alone, the positive predictive value (PPV) was 56%. Combination of the HC and FCD criteria raised the PPV to 78%, decreasing the number of false positives from 11 to four, without missing any of the 14 micB cases. Fetal vertical cranial biometric assessment in the mid-sagittal plane is feasible and correlates well with gestational age. In our series, a vertical cranial deformation was a frequent cause of a false Fmic diagnosis made on the basis of HC alone. Combination of the new vertical cranial biometric measurement with HC measurement can exclude these cases and thus improve diagnostic accuracy for Fmic. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Detection of osseous metastasis by 18F-NaF/18F-FDG PET/CT versus CT alone.

PubMed

Sampath, Srinath C; Sampath, Srihari C; Mosci, Camila; Lutz, Amelie M; Willmann, Juergen K; Mittra, Erik S; Gambhir, Sanjiv S; Iagaru, Andrei

2015-03-01

Sodium fluoride PET (18F-NaF) has recently reemerged as a valuable method for detection of osseous metastasis, with recent work highlighting the potential of coadministered 18F-NaF and 18F-FDG PET/CT in a single combined imaging examination. We further examined the potential of such combined examinations by comparing dual tracer 18F-NaF18/F-FDG PET/CT with CT alone for detection of osseous metastasis. Seventy-five participants with biopsy-proven malignancy were consecutively enrolled from a single center and underwent combined 18F-NaF/18F-FDG PET/CT and diagnostic CT scans. PET/CT as well as CT only images were reviewed in blinded fashion and compared with the results of clinical, imaging, or histological follow-up as a truth standard. Sensitivity of the combined 18F-NaF/18F-FDG PET/CT was higher than that of CT alone (97.4% vs 66.7%). CT and 18F-NaF/18F-FDG PET/CT were concordant in 73% of studies. Of 20 discordant cases, 18F-NaF/18F-FDG PET/CT was correct in 19 (95%). Three cases were interpreted concordantly but incorrectly, and all 3 were false positives. A single case of osseous metastasis was detected by CT alone, but not by 18F-NaF/18F-FDG PET/CT. Combined 18F-NaF/18F-FDG PET/CT outperforms CT alone and is highly sensitive and specific for detection of osseous metastases. The concordantly interpreted false-positive cases demonstrate the difficulty of distinguishing degenerative from malignant disease, whereas the single case of metastasis seen on CT but not PET highlights the need for careful review of CT images in multimodality studies.

[Importance of AFPplus-screening in daily practice. Evaluation of 2641 analyses].

PubMed

Longoni, S; Ackermann, M; Viollier, E H

1997-04-30

Since 1991 the measurement of 3 biochemical parameters for the risk assessment of trisomy 21 pregnancy (AFPplus, Alpha-check) is also offered by private laboratories in Switzerland. This work aimed at the proof of reliability of this risk analysis in the hands of practitioners and private laboratories. The investigated cohort included 2,641 pregnant women. An anonymous questionnaire on the outcome of pregnancy furnished informations in 97% of cases (2,561 cases). At a trisomy 21 risk cutoff of one to 380, 9% of the pregnant women had conspicuous AFPplus results (trisomy 21-risk > 1 to 380; age distribution at term: 17 to 45 years; median 29.4 years). Among the conspicuous cases were 8 with trisomy 21, 1 with trisomy 18, 5 spontaneous abortions and 3 special cases. Seven of a total of 9 trisomies were detected by the screening. From these data the following diagnostic parameters for AFPplus have been calculated: specificity 91.0%, sensitivity 77.8%, positive predictive value 99.9%, false positive rate 9.0%, false negative rate 22.2%. The use of AFPplus by a practitioner cooperating with a private laboratory thus reveals a detection rate comparable to that known from larger centers. AFPplus by a practitioner cooperating with a private laboratory thus reveals a detection rate comparable to that known from larger centers. AFPplus allows to individualize the statistical age-related risk of a pregnant women before age 35. Above age 35 AFPplus may support the indication for cases suitable for cytogenetic investigation. Thorough personal information of the patient before the 16th pregnancy week by the practitioner or by genetic counseling has without any doubt first priority.

Experimental investigation of false positive errors in auditory species occurrence surveys

USGS Publications Warehouse

Miller, David A.W.; Weir, Linda A.; McClintock, Brett T.; Grant, Evan H. Campbell; Bailey, Larissa L.; Simons, Theodore R.

2012-01-01

False positive errors are a significant component of many ecological data sets, which in combination with false negative errors, can lead to severe biases in conclusions about ecological systems. We present results of a field experiment where observers recorded observations for known combinations of electronically broadcast calling anurans under conditions mimicking field surveys to determine species occurrence. Our objectives were to characterize false positive error probabilities for auditory methods based on a large number of observers, to determine if targeted instruction could be used to reduce false positive error rates, and to establish useful predictors of among-observer and among-species differences in error rates. We recruited 31 observers, ranging in abilities from novice to expert, that recorded detections for 12 species during 180 calling trials (66,960 total observations). All observers made multiple false positive errors and on average 8.1% of recorded detections in the experiment were false positive errors. Additional instruction had only minor effects on error rates. After instruction, false positive error probabilities decreased by 16% for treatment individuals compared to controls with broad confidence interval overlap of 0 (95% CI: -46 to 30%). This coincided with an increase in false negative errors due to the treatment (26%; -3 to 61%). Differences among observers in false positive and in false negative error rates were best predicted by scores from an online test and a self-assessment of observer ability completed prior to the field experiment. In contrast, years of experience conducting call surveys was a weak predictor of error rates. False positive errors were also more common for species that were played more frequently, but were not related to the dominant spectral frequency of the call. Our results corroborate other work that demonstrates false positives are a significant component of species occurrence data collected by auditory methods. Instructing observers to only report detections they are completely certain are correct is not sufficient to eliminate errors. As a result, analytical methods that account for false positive errors will be needed, and independent testing of observer ability is a useful predictor for among-observer variation in observation error rates.

Characterisation of false-positive observations in botanical surveys

PubMed Central

2017-01-01

Errors in botanical surveying are a common problem. The presence of a species is easily overlooked, leading to false-absences; while misidentifications and other mistakes lead to false-positive observations. While it is common knowledge that these errors occur, there are few data that can be used to quantify and describe these errors. Here we characterise false-positive errors for a controlled set of surveys conducted as part of a field identification test of botanical skill. Surveys were conducted at sites with a verified list of vascular plant species. The candidates were asked to list all the species they could identify in a defined botanically rich area. They were told beforehand that their final score would be the sum of the correct species they listed, but false-positive errors counted against their overall grade. The number of errors varied considerably between people, some people create a high proportion of false-positive errors, but these are scattered across all skill levels. Therefore, a person’s ability to correctly identify a large number of species is not a safeguard against the generation of false-positive errors. There was no phylogenetic pattern to falsely observed species; however, rare species are more likely to be false-positive as are species from species rich genera. Raising the threshold for the acceptance of an observation reduced false-positive observations dramatically, but at the expense of more false negative errors. False-positive errors are higher in field surveying of plants than many people may appreciate. Greater stringency is required before accepting species as present at a site, particularly for rare species. Combining multiple surveys resolves the problem, but requires a considerable increase in effort to achieve the same sensitivity as a single survey. Therefore, other methods should be used to raise the threshold for the acceptance of a species. For example, digital data input systems that can verify, feedback and inform the user are likely to reduce false-positive errors significantly. PMID:28533972

Automated detection scheme of architectural distortion in mammograms using adaptive Gabor filter

NASA Astrophysics Data System (ADS)

Yoshikawa, Ruriha; Teramoto, Atsushi; Matsubara, Tomoko; Fujita, Hiroshi

2013-03-01

Breast cancer is a serious health concern for all women. Computer-aided detection for mammography has been used for detecting mass and micro-calcification. However, there are challenges regarding the automated detection of the architectural distortion about the sensitivity. In this study, we propose a novel automated method for detecting architectural distortion. Our method consists of the analysis of the mammary gland structure, detection of the distorted region, and reduction of false positive results. We developed the adaptive Gabor filter for analyzing the mammary gland structure that decides filter parameters depending on the thickness of the gland structure. As for post-processing, healthy mammary glands that run from the nipple to the chest wall are eliminated by angle analysis. Moreover, background mammary glands are removed based on the intensity output image obtained from adaptive Gabor filter. The distorted region of the mammary gland is then detected as an initial candidate using a concentration index followed by binarization and labeling. False positives in the initial candidate are eliminated using 23 types of characteristic features and a support vector machine. In the experiments, we compared the automated detection results with interpretations by a radiologist using 50 cases (200 images) from the Digital Database of Screening Mammography (DDSM). As a result, true positive rate was 82.72%, and the number of false positive per image was 1.39. There results indicate that the proposed method may be useful for detecting architectural distortion in mammograms.

High luminance monochrome vs. color displays: impact on performance and search

NASA Astrophysics Data System (ADS)

Krupinski, Elizabeth A.; Roehrig, Hans; Matsui, Takashi

2011-03-01

To determine if diagnostic accuracy and visual search efficiency with a high luminance medical-grade color display are equivalent to a high luminance medical-grade monochrome display. Six radiologists viewed DR chest images, half with a solitary pulmonary nodule and half without. Observers reported whether or not a nodule was present and their confidence in that decision. Total viewing time per image was recorded. On a subset of 15 cases eye-position was recorded. Confidence data were analyzed using MRMC ROC techniques. There was no statistically significant difference (F = 0.0136, p = 0.9078) between color (mean Az = 0.8981, se = 0.0065) and monochrome (mean Az = 0.8945, se = 0.0148) diagnostic performance. Total viewing time per image did not differ significantly (F = 0.392, p = 0.5315) as a function of color (mean = 27.36 sec, sd = 12.95) vs monochrome (mean = 28.04, sd = 14.36) display. There were no significant differences in decision dwell times (true and false, positive and negative) overall for color vs monochrome displays (F = 0.133, p = 0.7154). The true positive (TP) and false positive (FP) decisions were associated with the longest dwell times, the false negatives (FN) with slightly shorter dwell times, and the true negative decisions (TN) with the shortest (F = 50.552, p < 0.0001) and these trends were consistent for both color and monochrome displays. Current color medical-grade displays are suitable for primary diagnostic interpretation in clinical radiology.

Global Sensitivity Analysis with Small Sample Sizes: Ordinary Least Squares Approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, Michael J.; Liu, Wei; Sivaramakrishnan, Raghu

2016-12-21

A new version of global sensitivity analysis is developed in this paper. This new version coupled with tools from statistics, machine learning, and optimization can devise small sample sizes that allow for the accurate ordering of sensitivity coefficients for the first 10-30 most sensitive chemical reactions in complex chemical-kinetic mechanisms, and is particularly useful for studying the chemistry in realistic devices. A key part of the paper is calibration of these small samples. Because these small sample sizes are developed for use in realistic combustion devices, the calibration is done over the ranges of conditions in such devices, with amore » test case being the operating conditions of a compression ignition engine studied earlier. Compression ignition engines operate under low-temperature combustion conditions with quite complicated chemistry making this calibration difficult, leading to the possibility of false positives and false negatives in the ordering of the reactions. So an important aspect of the paper is showing how to handle the trade-off between false positives and false negatives using ideas from the multiobjective optimization literature. The combination of the new global sensitivity method and the calibration are sample sizes a factor of approximately 10 times smaller than were available with our previous algorithm.« less

[Study of the supra-aortic trunks using the humeral Seldinger technique and digitalized angiography of the aortic arch. Apropos of 175 cases].

PubMed

Boyer, L; Badère, J M; Dupont le Priol, P; Viallet, J F; Ribal, J P; Glanddier, G

1991-10-01

Screening of cerebrovascular disease by transbranchial arch injection. One hundred and seventy five patients underwent non selective intra arterial digital subtraction angiography using a transbranchial approach. Unilateral failure occurred in eight patients, but contralateral approach was then possible. Transient cerebral ischaemia affected one patient. Seven locoregional complications occurred, five of them underwent among the seventy three first procedures. Experience of the examining radiologist, duration of procedure and diameter of the catheter (4 or 5 F) are essential safety factors. Three false-negative and one false-positive in carotid bifurcations appears with surgical results reviews. This safe and efficient technique is often sufficient for a therapeutic decision, especially for surgery, but, in a few cases, additional selective injections can be necessary. Possible in out patients, this approach is chosen when femoral artery catheterization is impossible, or before reconstructive aorto-ilio-femoral surgery, to decrease septic risk.

Kepler Certified False Positive Table

NASA Technical Reports Server (NTRS)

Bryson, Stephen T.; Batalha, Natalie Marie; Colon, Knicole Dawn; Coughlin, Jeffrey Langer; Haas, Michael R.; Henze, Chris; Huber, Daniel; Morton, Tim; Rowe, Jason Frank; Mullally, Susan Elizabeth;

Cumulative risk of false positive test in relation to breast symptoms in mammography screening: a historical prospective cohort study.

PubMed

Singh, Deependra; Pitkäniemi, Janne; Malila, Nea; Anttila, Ahti

2016-09-01

Mammography has been found effective as the primary screening test for breast cancer. We estimated the cumulative probability of false positive screening test results with respect to symptom history reported at screen. A historical prospective cohort study was done using individual screening data from 413,611 women aged 50-69 years with 2,627,256 invitations for mammography screening between 1992 and 2012 in Finland. Symptoms (lump, retraction, and secretion) were reported at 56,805 visits, and 48,873 visits resulted in a false positive mammography result. Generalized linear models were used to estimate the probability of at least one false positive test and true positive at screening visits. The estimates were compared among women with and without symptoms history. The estimated cumulative probabilities were 18 and 6 % for false positive and true positive results, respectively. In women with a history of a lump, the cumulative probabilities of false positive test and true positive were 45 and 16 %, respectively, compared to 17 and 5 % with no reported lump. In women with a history of any given symptom, the cumulative probabilities of false positive test and true positive were 38 and 13 %, respectively. Likewise, women with a history of a 'lump and retraction' had the cumulative false positive probability of 56 %. The study showed higher cumulative risk of false positive tests and more cancers detected in women who reported symptoms compared to women who did not report symptoms at screen. The risk varies substantially, depending on symptom types and characteristics. Information on breast symptoms influences the balance of absolute benefits and harms of screening.

Detecting false positives in multielement designs: implications for brief assessments.

PubMed

Bartlett, Sara M; Rapp, John T; Henrickson, Marissa L

2011-11-01

The authors assessed the extent to which multielement designs produced false positives using continuous duration recording (CDR) and interval recording with 10-s and 1-min interval sizes. Specifically, they created 6,000 graphs with multielement designs that varied in the number of data paths, and the number of data points per data path, using a random number generator. In Experiment 1, the authors visually analyzed the graphs for the occurrence of false positives. Results indicated that graphs depicting only two sessions for each condition (e.g., a control condition plotted with multiple test conditions) produced the highest percentage of false positives for CDR and interval recording with 10-s and 1-min intervals. Conversely, graphs with four or five sessions for each condition produced the lowest percentage of false positives for each method. In Experiment 2, they applied two new rules, which were intended to decrease false positives, to each graph that depicted a false positive in Experiment 1. Results showed that application of new rules decreased false positives to less than 5% for all of the graphs except for those with two data paths and two data points per data path. Implications for brief assessments are discussed.

Response time as a discriminator between true- and false-positive responses in suprathreshold perimetry.

PubMed

Artes, Paul H; McLeod, David; Henson, David B

2002-01-01

To report on differences between the latency distributions of responses to stimuli and to false-positive catch trials in suprathreshold perimetry. To describe an algorithm for defining response time windows and to report on its performance in discriminating between true- and false-positive responses on the basis of response time (RT). A sample of 435 largely inexperienced patients underwent suprathreshold visual field examination on a perimeter that was modified to record RTs. Data were analyzed from 60,500 responses to suprathreshold stimuli and from 523 false-positive responses to catch trials. False-positive responses had much more variable latencies than responses to suprathreshold stimuli. An algorithm defining RT windows on the basis of z-transformed individual latency samples correctly identified more than 70% of false-positive responses to catch trials, whereas fewer than 3% of responses to suprathreshold stimuli were classified as false-positive responses. Latency analysis can be used to detect a substantial proportion of false-positive responses in suprathreshold perimetry. Rejection of such responses may increase the reliability of visual field screening by reducing variability and bias in a small but clinically important proportion of patients.

Peripleural lung disease detection based on multi-slice CT images

NASA Astrophysics Data System (ADS)

Matsuhiro, M.; Suzuki, H.; Kawata, Y.; Niki, N.; Nakano, Y.; Ohmatsu, H.; Kusumoto, M.; Tsuchida, T.; Eguchi, K.; Kaneko, M.

2015-03-01

With the development of multi-slice CT technology, obtaining accurate 3D images of lung field in a short time become possible. To support that, a lot of image processing methods need to be developed. Detection peripleural lung disease is difficult due to its existence out of lung region, because lung extraction is often performed based on threshold processing. The proposed method uses thoracic inner region extracted by inner cavity of bone as well as air region, covers peripleural lung diseased cases such as lung nodule, calcification, pleural effusion and pleural plaque. We applied this method to 50 cases including 39 peripleural lung diseased cases. This method was able to detect 39 peripleural lung disease with 2.9 false positive per case.

Confabulation versus experimentally induced false memories in Korsakoff patients.

PubMed

Van Damme, Ilse; d'Ydewalle, Géry

2010-09-01

The present study focuses on both the clinical symptom of confabulation and experimentally induced false memories in patients suffering from Korsakoff's syndrome. Despite the vast amount of case studies of confabulating patients and studies investigating false memories in the Deese-Roediger-McDermott (DRM) paradigm, the nature of Korsakoff patients' confabulatory behaviour and its association with DRM false memories have been rarely examined. Hence, the first aim of the present study was to evaluate confabulatory responses in a large sample of chronic Korsakoff patients and matched controls by means of the Dalla Barba Confabulation Battery. Second, the association between (provoked) confabulation and the patients' DRM false recognition performance was investigated. Korsakoff patients mainly confabulated in response to questions about episodic memory and questions to which the answer was unknown. A positive association was obtained between confabulation and the tendency to accept unstudied distractor words as being old in the DRM paradigm. On the other hand, there was a negative association between confabulation and false recognition of critical lures. The latter could be attributed to the importance of strategic retrieval at delayed memory testing.

Performance of the G4 Xpert® MTB/RIF assay for the detection of Mycobacterium tuberculosis and rifampin resistance: a retrospective case-control study of analytical and clinical samples from high- and low-tuberculosis prevalence settings.

PubMed

Dharan, Nila J; Blakemore, Robert; Sloutsky, Alex; Kaur, Devinder; Alexander, Richard C; Ghajar, Minoo; Musser, Kimberlee A; Escuyer, Vincent E; Rowlinson, Marie-Claire; Crowe, Susanne; Laniado-Laborin, Rafael; Valli, Eloise; Nabeta, Pamela; Johnson, Pamela; Alland, David

2016-12-20

The Xpert ® MTB/RIF (Xpert) assay is a rapid PCR-based assay for the detection of Mycobacterium tuberculosis complex DNA (MTBc) and mutations associated with rifampin resistance (RIF). An updated version introduced in 2011, the G4 Xpert, included modifications to probe B and updated analytic software. An analytical study was performed to assess Xpert detection of mutations associated with rifampin resistance in rifampin-susceptible and -resistant isolates. A clinical study was performed in which specimens from US and non-US persons suspected of tuberculosis (TB) were tested to determine Xpert performance characteristics. All specimens underwent smear microscopy, mycobacterial culture, conventional drug-susceptibility testing and Xpert testing; DNA from isolates with discordant rifampin resistance results was sequenced. Among 191 laboratory-prepared isolates in the analytical study, Xpert sensitivity for detection of rifampin resistance associated mutations was 97.7% and specificity was 90.8%, which increased to 99.0% after DNA sequencing analysis of the discordant samples. Of the 1,096 subjects in the four clinical studies, 49% were from the US. Overall, Xpert detected MTBc in 439 of 468 culture-positive specimens for a sensitivity of 93.8% (95% confidence interval [CI]: 91.2%-95.7%) and did not detect MTBc in 620 of 628 culture-negative specimens for a specificity of 98.7% (95% CI: 97.5%-99.4%). Sensitivity was 99.7% among smear-positive cases, and 76.1% among smear-negative cases. Non-determinate MTBc detection and false-positive RIF resistance results were low (1.2 and 0.9%, respectively). The updated Xpert assay retained the high sensitivity and specificity of the previous assay versions and demonstrated low rates of non-determinate and RIF resistance false positive results.

Benefit of computer-aided detection analysis for the detection of subsolid and solid lung nodules on thin- and thick-section CT.

PubMed

Godoy, Myrna C B; Kim, Tae Jung; White, Charles S; Bogoni, Luca; de Groot, Patricia; Florin, Charles; Obuchowski, Nancy; Babb, James S; Salganicoff, Marcos; Naidich, David P; Anand, Vikram; Park, Sangmin; Vlahos, Ioannis; Ko, Jane P

2013-01-01

The objective of our study was to evaluate the impact of computer-aided detection (CAD) on the identification of subsolid and solid lung nodules on thin- and thick-section CT. For 46 chest CT examinations with ground-glass opacity (GGO) nodules, CAD marks computed using thin data were evaluated in two phases. First, four chest radiologists reviewed thin sections (reader(thin)) for nodules and subsequently CAD marks (reader(thin) + CAD(thin)). After 4 months, the same cases were reviewed on thick sections (reader(thick)) and subsequently with CAD marks (reader(thick) + CAD(thick)). Sensitivities were evaluated. Additionally, reader(thick) sensitivity with assessment of CAD marks on thin sections was estimated (reader(thick) + CAD(thin)). For 155 nodules (mean, 5.5 mm; range, 4.0-27.5 mm)-74 solid nodules, 22 part-solid (part-solid nodules), and 59 GGO nodules-CAD stand-alone sensitivity was 80%, 95%, and 71%, respectively, with three false-positives on average (0-12) per CT study. Reader(thin) + CAD(thin) sensitivities were higher than reader(thin) for solid nodules (82% vs 57%, p < 0.001), part-solid nodules (97% vs 81%, p = 0.0027), and GGO nodules (82% vs 69%, p < 0.001) for all readers (p < 0.001). Respective sensitivities for reader(thick), reader(thick) + CAD(thick), reader(thick) + CAD(thin) were 40%, 58% (p < 0.001), and 77% (p < 0.001) for solid nodules; 72%, 73% (p = 0.322), and 94% (p < 0.001) for part-solid nodules; and 53%, 58% (p = 0.008), and 79% (p < 0.001) for GGO nodules. For reader(thin), false-positives increased from 0.64 per case to 0.90 with CAD(thin) (p < 0.001) but not for reader(thick); false-positive rates were 1.17, 1.19, and 1.26 per case for reader(thick), reader(thick) + CAD(thick), and reader(thick) + CAD(thin), respectively. Detection of GGO nodules and solid nodules is significantly improved with CAD. When interpretation is performed on thick sections, the benefit is greater when CAD marks are reviewed on thin rather than thick sections.

Prescription drugs associated with false-positive results when using faecal immunochemical tests for colorectal cancer screening.

PubMed

Ibáñez-Sanz, Gemma; Garcia, Montse; Rodríguez-Moranta, Francisco; Binefa, Gemma; Gómez-Matas, Javier; Domènech, Xènia; Vidal, Carmen; Soriano, Antonio; Moreno, Víctor

2016-10-01

The most common side effect in population screening programmes is a false-positive result which leads to unnecessary risks and costs. To identify factors associated with false-positive results in a colorectal cancer screening programme with the faecal immunochemical test (FIT). Cross-sectional study of 472 participants with a positive FIT who underwent colonoscopy for confirmation of diagnosis between 2013 and 2014. A false-positive result was defined as having a positive FIT (≥20μg haemoglobin per gram of faeces) and follow-up colonoscopy without intermediate/high-risk lesions or cancer. Women showed a two-fold increased likelihood of a false-positive result compared with men (adjusted OR, 2.3; 95%CI, 1.5-3.4), but no female-specific factor was identified. The other variables associated with a false-positive result were successive screening (adjusted OR, 1.5; 95%CI, 1.0-2.2), anal disorders (adjusted OR, 3.1; 95%CI, 2.1-4.5) and the use of proton pump inhibitors (adjusted OR, 1.8; 95%CI, 1.1-2.9). Successive screening and proton pump inhibitor use were associated with FP in men. None of the other drugs were related to a false-positive FIT. Concurrent use of proton pump inhibitors at the time of FIT might increase the likelihood of a false-positive result. Further investigation is needed to determine whether discontinuing them could decrease the false-positive rate. Copyright © 2016 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

An assessment of false positive rates for malaria rapid diagnostic tests caused by non-Plasmodium infectious agents and immunological factors.

PubMed

Gatton, Michelle L; Ciketic, Sadmir; Barnwell, John W; Cheng, Qin; Chiodini, Peter L; Incardona, Sandra; Bell, David; Cunningham, Jane; González, Iveth J

2018-01-01

Malaria rapid diagnostic tests (RDTs) can produce false positive (FP) results in patients with human African trypanosomiasis and rheumatoid factor (RF), but specificity against other infectious agents and immunological factors is largely unknown. Low diagnostic specificity caused by cross-reactivity may lead to over-estimates of the number of malaria cases and over-use of antimalarial drugs, at the cost of not diagnosing and treating the true underlying condition. Data from the WHO Malaria RDT Product Testing Programme was analysed to assess FP rates of 221 RDTs against four infectious agents (Chagas, dengue, Leishmaniasis and Schistosomiasis) and four immunological factors (anti-nuclear antibody, human anti-mouse antibody (HAMA), RF and rapid plasma regain). Only RDTs with a FP rate against clean negative samples less than 10% were included. Paired t-tests were used to compare product-specific FP rates on clean negative samples and samples containing non-Plasmodium infectious agents and immunological factors. Forty (18%) RDTs showed no FP results against any tested infectious agent or immunological factor. In the remaining RDTs significant and clinically relevant increases in FP rates were observed for samples containing HAMA and RF (P<0.001). There were significant correlations between product-matched FP rates for RF and HAMA on all RDT test bands (P<0.001), and FP rates for each infectious agent and immunological factor were also correlated between test bands of combination RDTs (P≤0.002). False positive results against non-Plasmodium infectious agents and immunological factors does not appear to be a universal property of malaria RDTs. However, since many malaria RDTs have elevated FP rates against HAMA and RF positive samples practitioners may need to consider the possibility of false positive results for malaria in patients with conditions that stimulate HAMA or RF.

Sensitivity of fetal RHD screening for safe guidance of targeted anti-D immunoglobulin prophylaxis: prospective cohort study of a nationwide programme in the Netherlands.

PubMed

de Haas, Masja; Thurik, Florentine F; van der Ploeg, Catharina P B; Veldhuisen, Barbera; Hirschberg, Hoang; Soussan, Aicha Ait; Woortmeijer, Heleen; Abbink, Frithjofna; Page-Christiaens, Godelieve C M L; Scheffer, Peter G; Ellen van der Schoot, C

2016-11-07

 To determine the accuracy of non-invasive fetal testing for the RHD gene in week 27 of pregnancy as part of an antenatal screening programme to restrict anti-D immunoglobulin use to women carrying a child positive for RHD DESIGN:  Prospectively monitoring of fetal RHD testing accuracy compared with serological cord blood typing on introduction of the test. Fetal RHD testing was performed with a duplex real time quantitative polymerase chain reaction, with cell-free fetal DNA isolated from 1 mL of maternal plasma The study period was between 4 July 2011 and 7 October 2012. The proportion of women participating in screening was determined.  Nationwide screening programme, the Netherlands. Tests are performed in a centralised setting.  25 789 RhD negative pregnant women.  Sensitivity, specificity, false negative rate, and false positive rate of fetal RHD testing compared with serological cord blood typing; proportion of technical failures; and compliance to the screening programme.  A fetal RHD test result and serological cord blood result were available for 25 789 pregnancies. Sensitivity for detection of fetal RHD was 99.94% (95% confidence interval 99.89% to 99.97%) and specificity was 97.74% (97.43% to 98.02%). Nine false negative results for fetal RHD testing were registered (0.03%, 95% confidence interval 0.01% to 0.06%). In two cases these were due to technical failures. False positive fetal RHD testing results were registered for 225 samples (0.87%, 0.76% to 0.99%). Weak RhD expression was shown in 22 of these cases, justifying anti-D immunoglobulin use. The negative and positive predictive values were 99.91% (95% confidence interval 99.82% to 99.95%) and 98.60% (98.40% to 98.77%), respectively. More than 98% of the women participated in the screening programme.  Fetal RHD testing in week 27 of pregnancy as part of a national antenatal screening programme is highly reliable and can be used to target both antenatal and postnatal anti-D immunoglobulin use. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

[Predictive value and sensibility of hospital discharge system (PMSI) compared to cancer registries for thyroïd cancer (1999-2000)].

PubMed

Carré, N; Uhry, Z; Velten, M; Trétarre, B; Schvartz, C; Molinié, F; Maarouf, N; Langlois, C; Grosclaude, P; Colonna, M

2006-09-01

Cancer registries have a complete recording of new cancer cases occurring among residents of a specific geographic area. In France, they cover only 13% of the population. For thyroid cancer, where incidence rate is highly variable according to the district conversely to mortality, national incidence estimates are not accurate. A nationwide database, such as hospital discharge system, could improve this estimate but its positive predictive value and sensibility should be evaluated. The positive predictive value and the sensitivity for thyroid cancer case ascertainment (ICD-10) of the national hospital discharge system in 1999 and 2000 were estimated using the cancer registries database of 10 French districts as gold standard. The linkage of the two databases required transmission of nominative information from the health facilities of the study. From the registries database, a logistic regression analysis was carried out to identify factors related to being missed by the hospital discharge system. Among the 973 standardized discharge charts selected from the hospital discharge system, 866 were considered as true positive cases, and 107 as false positive. Forty five of the latter group were prevalent cases. The predictive positive value was 89% (95% confidence interval (CI): 87-91%) and did not differ according to the district (p=0,80). According to the cancer registries, 322 thyroid cancer cases diagnosed in 1999 or 2000 were missed by the hospital discharge system. Thus, the sensitivity of this latter system was 73% (70-76%) and varied significantly from 62% to 85% across districts (p<0.001) and according to the type of health facility (p<0.01). Predictive positive value of the French hospital discharge system for ascertainment of thyroid cancer cases is high and stable across districts. Sensitivity is lower and varies significantly according to the type of health facility and across districts, which limits the interest of this database for a national estimate of thyroid cancer incidence rate.

The epidemiology of pertussis in the Australian Capital Territory, 1999 to 2005--epidemics of testing, disease or false positives?

PubMed

Wylks, Clare E; Ewald, Ben; Guest, Charles

2007-12-01

The increase in pertussis notifications since the 1990s in many countries, including Australia, has been attributed to improved diagnosis. This study aimed to describe the epidemiology of pertussis in the Australian Capital Territory from 1999 to 2005, determine whether the apparent changes could be accounted for by greater recognition and testing, and explore the impact of false positive serology results associated with faulty test kits. The Australian Capital Territory resident notification, laboratory and separation data from 1999 to 2005 were examined and the proportions of positive tests across time periods and age groups compared. Notification rates increased in the years 2000, 2003 and 2005. There was a shift in the age distribution of cases, from children and teenagers in 2000, to teenagers in 2003 and adults in 2005. Testing activity and notification activity were closely related. Comparing the epidemic periods to the preceding inter-epidemic periods, the proportion of positive tests was maintained or increased for all age groups combined and for adults and children (e.g. statistically significant increase from 7.8% to 14.0% in the 2005 epidemic in adults). During each epidemic the proportion of positive tests was statistically significantly higher in the age group with the highest notification activity. Despite similar testing rates in adults in 2003 and 2005, greater disease activity was reported in 2005. Although the numbers were small, polymerase chain reaction and culture positive test results increased in 2003 but not in 2005. The proportion of positive polymerase chain reaction results increased in 2003, providing strong evidence that the apparent epidemic of 2003 was due to a true increase in underlying disease activity. Because of the uncertainty surrounding the timing of the false positive serology results, the study provides weaker support for a true epidemic of pertussis in 2005.

A correlation study of diagnostic fine-needle aspiration with histologic diagnosis in cystic neck lesions.

PubMed

Moatamed, Neda A; Naini, Bita V; Fathizadeh, Payman; Estrella, Julie; Apple, Sophia K

2009-10-01

The clinical diagnosis of a mass in the neck region encompasses a wide spectrum of differential diagnosis. Fine-needle aspiration is a quick and safe technique, which can provide useful information for initial assessment and further therapeutic measures. The aim of this retrospective study was to evaluate the performance characteristics of the fine-needle aspiration (FNA) in cystic neck lesions. Of 142 patients with FNA for cystic neck masses during 2002-2007, 92 cases were selected with a follow-up histologic diagnosis, excluding the cystic colloid nodule of the thyroid. The cases were divided into salivary gland cystic neck (37 patients) and non-salivary cystic neck (55 patients) mass groups. False-positive and false-negative diagnoses were applied only to the malignant lesions after confirmation by histopathology. In the first group, nine malignant and 28 benign diagnoses were made by FNA; of which three were false-negative. In the second group, there were nine malignant and 46 benign diagnoses with three false negatives. The overall performance of the FNA showed 76% sensitivity and 100% specificity. In conclusion, FNA of the cystic neck lesions offers an invaluable and highly specific initial diagnostic approach for the management of the patients. (c) 2009 Wiley-Liss, Inc.

[Roaming through methodology. XXXII. False test results].

PubMed

van der Weijden, T; van den Akker, M

2001-05-12

The number of requests for diagnostic tests is rising. This leads to a higher chance of false test results. The false-negative proportion of a test is the proportion of negative test results among the diseased subjects. The false-positive proportion is the proportion of positive test results among the healthy subjects. The calculation of the false-positive proportion is often incorrect. For example, instead of 1 minus the specificity it is calculated as 1 minus the positive predictive value. This can lead to incorrect decision-making with respect to the application of the test. Physicians must apply diagnostic tests in such a way that the risk of false test results is minimal. The patient should be aware that a perfectly conclusive diagnostic test is rare in medical practice, and should more often be informed of the implications of false-positive and false-negative test results.

Chronic Chagas disease: PCR-xenodiagnosis without previous microscopic observation is a useful tool to detect viable Trypanosoma cruzi.

PubMed

Saavedra, Miguel; Zulantay, Inés; Apt, Werner; Martínez, Gabriela; Rojas, Antonio; Rodríguez, Jorge

2013-01-01

We evaluate the elimination of the microscopic stage of conventional xenodiagnosis (XD) to optimize the parasitological diagnosis of Trypanosoma cruzi in chronic Chagas disease. To this purpose we applied under informed consent two XD cages to 150 Chilean chronic chagasic patients. The fecal samples (FS) of the triatomines at 30, 60 and 90 days post feeding were divided into two parts: in one a microscopic search for mobile trypomastigote and/or epimastigote forms was performed. In the other part, DNA extraction-purification for PCR directed to the conserved region of kDNA minicircles of trypanosomes (PCR-XD), without previous microscopic observation was done. An XD was considered positive when at least one mobile T. cruzi parasite in any one of three periods of incubation was observed, whereas PCR-XD was considered positive when the 330 bp band specific for T. cruzi was detected. 25 of 26 cases with positive conventional XD were PCR-XD positive (concordance 96.2%), whereas 85 of 124 cases with negative conventional XD were positive by PCR-XD (68.5%). Human chromosome 12 detected by Real-time PCR used as exogenous internal control of PCR-XD reaction allowed to discounting of PCR inhibition and false negative in 40 cases with negative PCR-XD. PCR-XD performed without previous microscopic observation is a useful tool for detection of viable parasites with higher efficiency then conventional XD.

Accurate decisions in an uncertain world: collective cognition increases true positives while decreasing false positives.

PubMed

Wolf, Max; Kurvers, Ralf H J M; Ward, Ashley J W; Krause, Stefan; Krause, Jens

2013-04-07

In a wide range of contexts, including predator avoidance, medical decision-making and security screening, decision accuracy is fundamentally constrained by the trade-off between true and false positives. Increased true positives are possible only at the cost of increased false positives; conversely, decreased false positives are associated with decreased true positives. We use an integrated theoretical and experimental approach to show that a group of decision-makers can overcome this basic limitation. Using a mathematical model, we show that a simple quorum decision rule enables individuals in groups to simultaneously increase true positives and decrease false positives. The results from a predator-detection experiment that we performed with humans are in line with these predictions: (i) after observing the choices of the other group members, individuals both increase true positives and decrease false positives, (ii) this effect gets stronger as group size increases, (iii) individuals use a quorum threshold set between the average true- and false-positive rates of the other group members, and (iv) individuals adjust their quorum adaptively to the performance of the group. Our results have broad implications for our understanding of the ecology and evolution of group-living animals and lend themselves for applications in the human domain such as the design of improved screening methods in medical, forensic, security and business applications.

Accurate decisions in an uncertain world: collective cognition increases true positives while decreasing false positives

PubMed Central

Wolf, Max; Kurvers, Ralf H. J. M.; Ward, Ashley J. W.; Krause, Stefan; Krause, Jens

2013-01-01

In a wide range of contexts, including predator avoidance, medical decision-making and security screening, decision accuracy is fundamentally constrained by the trade-off between true and false positives. Increased true positives are possible only at the cost of increased false positives; conversely, decreased false positives are associated with decreased true positives. We use an integrated theoretical and experimental approach to show that a group of decision-makers can overcome this basic limitation. Using a mathematical model, we show that a simple quorum decision rule enables individuals in groups to simultaneously increase true positives and decrease false positives. The results from a predator-detection experiment that we performed with humans are in line with these predictions: (i) after observing the choices of the other group members, individuals both increase true positives and decrease false positives, (ii) this effect gets stronger as group size increases, (iii) individuals use a quorum threshold set between the average true- and false-positive rates of the other group members, and (iv) individuals adjust their quorum adaptively to the performance of the group. Our results have broad implications for our understanding of the ecology and evolution of group-living animals and lend themselves for applications in the human domain such as the design of improved screening methods in medical, forensic, security and business applications. PMID:23407830

Use of magnetic resonance imaging for the investigation of orbital disease in small animals.

PubMed

Dennis, R

2000-04-01

Twenty-five small animal patients presenting with signs of orbital disease were investigated using magnetic resonance imaging (MRI) in an attempt to assess the value of this imaging technique for diagnosis. All patients were also examined using ultrasonography, and skull radiography was performed in 20 of these animals. The final diagnoses included neoplasia, inflammatory disease and foreign body penetration. MRI produced detailed images of orbital tissues and provided more information about the extent of pathology than the other imaging techniques; a correct diagnosis based solely on the MRI scan was made in 22 cases. Radiography was found to be helpful only in cases in which neoplastic disease extended markedly beyond the confines of the orbit into the nasal chamber and paranasal sinuses. Radiographic changes other than soft tissue swelling were not evident in other orbital disease processes. Ultrasonography gave both false negative and false positive diagnoses for neoplastic masses, although it allowed the correct diagnosis of both cases of foreign bodies and one of the three cases of retrobulbar abscesses in this series. MRI is recommended for patients in which radiography and ultrasonography fall to produce a confident diagnosis or for which surgery is proposed.

An analysis of false positive reactions occurring with the Captia Syph G EIA.

PubMed Central

Ross, J; Moyes, A; Young, H; McMillan, A

1991-01-01

AIM--The Captia Syph G enzyme immuno assay (EAI) offers the potential for the rapid automated detection of syphilis antibodies. This study was designed to assess the role of other sexually transmitted diseases (STDs) in producing false positive reactions in the Captia Syph G EIA. The role of rheumatoid factor (RF) as a potential source of false positives was also analysed. METHODS--Patients who attended a genitourinary medicine (GUM) department and gave a false positive reaction with the EIA between 1988 and 1990 were compared with women undergoing antenatal testing and with the control clinic population (EIA negative) over the same time period. The incidence of sexually transmitted disease (STD) in the clinic population and the false positive reactors was measured in relation to gonorrhoea, chlamydia, genital warts, candidiasis, "other conditions not requiring treatment" and "other conditions requiring treatment." Male: female sex ratios were also compared. Ninety two RF positive sera were analysed with the EIA. RESULTS--The rate of false positive reactions did not differ with respect to the diagnosis within the GUM clinic population. The antenatal group of women, however, had a lower incidence of false positive reactions than the GUM clinic group. No RF positive sera were positive on Captia Syph G EIA testing. CONCLUSIONS--There is no cross reaction between Captia Syph G EIA and any specific STD or with RF positive sera. The lower incidence of false positive reactions in antenatal women is unexplained but may be related to physiological changes associated with pregnancy. PMID:1743715

How Reliable Is the Alpha-defensin Immunoassay Test for Diagnosing Periprosthetic Joint Infection? A Prospective Study.

PubMed

Bonanzinga, Tommaso; Zahar, Akos; Dütsch, Michael; Lausmann, Christian; Kendoff, Daniel; Gehrke, Thorsten

2017-02-01

A key issue in the treatment of periprosthetic joint infection (PJI) is the correct diagnosis. The main problem is lack of diagnostic tools able to diagnose a PJI with high accuracy. Alpha-defensin has been proposed as a possible solution, but in the current literature, there is a lack of independent validation. We performed a prospective study to determine (1) what is the sensitivity, specificity, and positive and the negative predictive values of the alpha-defensin immunoassay test in diagnosing PJI; and (2) which clinical features may be responsible for false-positive and false-negative results? Preoperative aspiration was performed in all patients presenting with a painful hip/knee arthroplasty, including both primary and revision implants. Metallosis, other inflammatory comorbidities, and previous/concomitant antibiotic therapy were not considered as exclusion criteria. An inadequate amount of synovial fluid for culture was an exclusion criterion. A total of 156 patients (65 knees, 91 hips) were included in this prospective study. At the time of revision, synovial fluid samples were taken to perform the alpha-defensin assay. During surgical débridement of tissue, samples for cultures and histologic evaluation were taken, and samples were cultured until positive or until negative at 14 days. A diagnosis of PJI was confirmed in 29 patients according to the International Consensus Group on PJI. The sensitivity of the alpha-defensin immunoassay was 97% (95% confidence interval [CI], 92%-99%), the specificity was 97% (95% CI, 92%-99%), the positive predictive value was 88% (95% CI, 81%-92%), and the negative predictive value was 99% (95% CI, 96%-99%). Among four false-positive patients, two had metallosis and one had polyethylene wear. The false-negative case presented with a draining sinus, and intraoperative cultures were also negative. Alpha-defensin assay appears to be a reliable test, but followup evaluation is needed to estimate longer term performance of the test. The authors believe that alpha-defensin has demonstrated itself to be sufficiently robust that PJI diagnostic criteria now should include this test. Future studies are needed to compare the differences among the diagnostic capability of the available tests, in particular when metallosis is present, because metallosis may predispose the test to a false-positive result. Level I, diagnostic study.

Rare association of celiac disease with myasthenia gravis in a patient with other immune disorders: a case report.

PubMed

de Almeida Menezes, Marcela; Ribeiro Cabral, Vírginia Lúcia; Lorena, Sônia S; Nucci, Anamarli; Andrade Santana, Priscila; Queiroz Silva, Cecília

2016-09-01

Celiac disease is described in association with several autoimmune diseases, but rarely with myasthenia gravis. We describe the case of a 31-year-old white woman with celiac disease who presented manifestations related to a hyperactive immune system, including macroamylasemia, false-positive anti-HCV, positive antinuclear antibody, and Raynaud's phenomenon. The introduction of a gluten-free diet (GFD) resolved these features, but myasthenia gravis (MG) symptoms unexpectedly occurred on that occasion. The role of a GFD in the course of autoimmune diseases has been studied and improvement has been reported in many diseases. However, there is no consensus in the literature regarding the course of neurological disorders associated with celiac disease. In the present case, a GFD did not prevent the appearance of symptoms related to myasthenia gravis. There are few reports on the association of celiac disease with myasthenia gravis and therefore little is known about the course and time of onset of myasthenia in celiac patients. The present case increases the knowledge about this unusual autoimmune neurological disease associated with celiac disease.

[Streptococcal pharyngitis: clinical suspicion versus diagnosis].

PubMed

Morais, Sofia; Teles, Andreia; Ramalheira, Elmano; Roseta, José

2009-01-01

Pharyngitis is a very prevalent illness in the ambulatory care setting. Its diagnosis is a challenge, especially in the differentiation between the viric and streptococcal causes. A formulary was made to register the clinical and laboratory data; a throat swab for culture was obtained from all the children who presented to the emergency department with sore throat and/or signs of pharyngitis/tonsillitis, for a period of three months (15th of April to 15th of July of 2006). The signs and symptoms, prescribed antibiotherapy and frequency of false diagnostics were evaluated and the clinical suspicion compared with the diagnosis by culture. 158 children were evaluated, with a median age of four years, with a male predominance (56%). The period that showed the greatest number of cases was the first fifteen days of May. Forty-three percent of the cultures were positive for Streptococcus pyogenes. The more frequent signs and symptoms in pharyngitis were pharyngeal erythema (98%), fever (86%) and sore throat (78%). A significative statistical difference was found for cough, scarlatiniform rash, tonsillar exudate, palatal petechiae and tonsillar swelling. Of the signs and symptoms studied, only three of them presented a positive predictive value superior to 50%: scarlatiniform rash (85%), palatal petechiae (63%) and cough (57%). The presence of tonsillar exudate had a positive predictive value for non-streptococcal pharyngitis of 70%. Fifty-three percent of the doctors considered streptococcal pharyngitis highly probable, and from this, 56% had a positive culture for Streptococcus. Those who considered a low probability, the culture was positive in 28%. There were 37% of false diagnosis. The distinction between streptococcal pharyngitis and non-streptococcal pharyngitis is not always correct when based on clinical characteristics. The use of diagnostic tests is important in order to avoid unnecessary antibiotherapy as well as to allow the correct use in the positive cases.

[Systematic detection of physical child abuse at emergency rooms].

PubMed

Sittig, J S; Uiterwaal, C S P M; Moons, K G M; Russel, I M B; Nievelstein, R A J; Nieuwenhuis, E E S; van de Putte, E M

2016-01-01

The aim of our diagnostic accuracy study Child Abuse Inventory at Emergency Rooms (CHAIN-ER) was to establish whether a widely used checklist accurately detects or excludes physical abuse among children presenting to ERs with physical injury. A large multicentre study with a 6-month follow-up in 4 ERs in The Netherlands. Participants were 4290 children aged 0-7 years, attending the ER because of physical injury. All children were systematically tested with an easy-to-use child abuse checklist (index test). A national expert panel (reference standard) retrospectively assessed all children with positive screens and a 15% random sample of the children with negative screens for physical abuse, using additional information, namely, an injury history taken by a paediatrician, information provided by the general practitioner, youth doctor and social services by structured questionnaires, and 6-month follow-up information. Our main outcome measure was physical child abuse; secondary outcome measure was injury due to neglect and need for help. 4253/4290 (99%) parents agreed to follow-up. At a prevalence of 0.07% (3/4253) for inflicted injury by expert panel decision, the positive predictive value of the checklist was 0.03 (95% CI 0.006 to 0.085), and the negative predictive value 1.0 (0.994 to 1.0). There was 100% (93 to 100) agreement about inflicted injury in children, with positive screens between the expert panel and child abuse experts. Rare cases of inflicted injury among preschool children presenting at ERs for injury are very likely captured by easy-to-use checklists, but at very high false-positive rates. Subsequent assessment by child abuse experts can be safely restricted to children with positive screens at very low risk of missing cases of inflicted injury. Because of the high false positive rate, we do advise careful prior consideration of cost-effectiveness and clinical and societal implications before de novo implementation.

Usefulness of a break-apart FISH assay in the diagnosis of Xp11.2 translocation renal cell carcinoma.

PubMed

Kim, Soo Hee; Choi, Yoomi; Jeong, Hae Yeon; Lee, Kyoungbun; Chae, Ji Youn; Moon, Kyung Chul

2011-09-01

Xp11.2 translocation renal cell carcinoma (RCC) is a rare subtype of RCC predominantly reported in young patients. It results from gene fusions between the transcription factor E3 (TFE3) gene, which is located on chromosome Xp11.2, and various fusion partners. Recently, a dual color, break-apart fluorescence in situ hybridization (FISH) assay to detect Xp11.2 translocation was reported. We performed this study to evaluate the usefulness of the FISH assay in the diagnosis of Xp11.2 translocation RCC using a commercially available TFE3 break-apart probe. We immunohistochemically analyzed TFE3 nuclear expression in 809 cases of RCCs using 14 tissue microarray blocks and selected nine cases those showed moderate to strong positive nuclear immunoreactivity for TFE3. The extent of TFE3 nuclear expression was variable. The TFE3 FISH assay was performed in these 9 selected cases and 44 negative control cases. Only four out of nine selected cases showed the TFE3 break-apart signal. TFE3 FISH-positive cases mainly showed diffuse and strong TFE3 immunopositivity, but one case revealed focal and moderate TFE3 staining. On the contrary, TFE3 FISH-negative cases mainly revealed focal and moderate TFE3 immunoreactivity, however, one FISH-negative case revealed diffuse and strong TFE3 nuclear immunopositivity. All negative control cases revealed normal TFE3 FISH results. Our results reveal that TFE3 immunohistochemistry can show false-positive results, and that the TFE3 break-apart FISH assay is a useful complementary method for confirming the diagnosis of Xp11.2 translocation RCC.

Automatic detection of apical roots in oral radiographs

NASA Astrophysics Data System (ADS)

Wu, Yi; Xie, Fangfang; Yang, Jie; Cheng, Erkang; Megalooikonomou, Vasileios; Ling, Haibin

2012-03-01

The apical root regions play an important role in analysis and diagnosis of many oral diseases. Automatic detection of such regions is consequently the first step toward computer-aided diagnosis of these diseases. In this paper we propose an automatic method for periapical root region detection by using the state-of-theart machine learning approaches. Specifically, we have adapted the AdaBoost classifier for apical root detection. One challenge in the task is the lack of training cases especially for diseased ones. To handle this problem, we boost the training set by including more root regions that are close to the annotated ones and decompose the original images to randomly generate negative samples. Based on these training samples, the Adaboost algorithm in combination with Haar wavelets is utilized in this task to train an apical root detector. The learned detector usually generates a large amount of true and false positives. In order to reduce the number of false positives, a confidence score for each candidate detection result is calculated for further purification. We first merge the detected regions by combining tightly overlapped detected candidate regions and then we use the confidence scores from the Adaboost detector to eliminate the false positives. The proposed method is evaluated on a dataset containing 39 annotated digitized oral X-Ray images from 21 patients. The experimental results show that our approach can achieve promising detection accuracy.

Guess LOD approach: sufficient conditions for robustness.

PubMed

Williamson, J A; Amos, C I

1995-01-01

Analysis of genetic linkage between a disease and a marker locus requires specifying a genetic model describing both the inheritance pattern and the gene frequencies of the marker and trait loci. Misspecification of the genetic model is likely for etiologically complex diseases. In previous work we have shown through analytic studies that misspecifying the genetic model for disease inheritance does not lead to excess false-positive evidence for genetic linkage provided the genetic marker alleles of all pedigree members are known, or can be inferred without bias from the data. Here, under various selection or ascertainment schemes we extend these previous results to situations in which the genetic model for the marker locus may be incorrect. We provide sufficient conditions for the asymptotic unbiased estimation of the recombination fraction under the null hypothesis of no linkage, and also conditions for the limiting distribution of the likelihood ratio test for no linkage to be chi-squared. Through simulation studies we document some situations under which asymptotic bias can result when the genetic model is misspecified. Among those situations under which an excess of false-positive evidence for genetic linkage can be generated, the most common is failure to provide accurate estimates of the marker allele frequencies. We show that in most cases false-positive evidence for genetic linkage is unlikely to result solely from the misspecification of the genetic model for disease or trait inheritance.

Revisiting Recombination Signal in the Tick-Borne Encephalitis Virus: A Simulation Approach

PubMed Central

Johansson, Magnus; Norberg, Peter

2016-01-01

The hypothesis of wide spread reticulate evolution in Tick-Borne Encephalitis virus (TBEV) has recently gained momentum with several publications describing past recombination events involving various TBEV clades. Despite a large body of work, no consensus has yet emerged on TBEV evolutionary dynamics. Understanding the occurrence and frequency of recombination in TBEV bears significant impact on epidemiology, evolution, and vaccination with live vaccines. In this study, we investigated the possibility of detecting recombination events in TBEV by simulating recombinations at several locations on the virus’ phylogenetic tree and for different lengths of recombining fragments. We derived estimations of rates of true and false positive for the detection of past recombination events for seven recombination detection algorithms. Our analytical framework can be applied to any investigation dealing with the difficult task of distinguishing genuine recombination signal from background noise. Our results suggest that the problem of false positives associated with low detection P-values in TBEV, is more insidious than generally acknowledged. We reappraised the recombination signals present in the empirical data, and showed that reliable signals could only be obtained in a few cases when highly genetically divergent strains were involved, whereas false positives were common among genetically similar strains. We thus conclude that recombination among wild-type TBEV strains may occur, which has potential implications for vaccination with live vaccines, but that these events are surprisingly rare. PMID:27760182

Autonomic responses to correct outcomes and interaction errors during single-switch scanning among children with severe spastic quadriplegic cerebral palsy

PubMed Central

2014-01-01

Background The combination of single-switch access technology and scanning is the most promising means of augmentative and alternative communication for many children with severe physical disabilities. However, the physical impairment of the child and the technology’s limited ability to interpret the child’s intentions often lead to false positives and negatives (corresponding to accidental and missed selections, respectively) occurring at rates that frustrate the user and preclude functional communication. Multiple psychophysiological studies have associated cardiac deceleration and increased phasic electrodermal activity with self-realization of errors among able-bodied individuals. Thus, physiological measurements have potential utility at enhancing single-switch access, provided that such prototypical autonomic responses exist in persons with profound disabilities. Methods The present case series investigated the autonomic responses of three pediatric single-switch users with severe spastic quadriplegic cerebral palsy, in the context of a single-switch letter matching activity. Each participant exhibited distinct autonomic responses to activity engagement. Results Our analysis confirmed the presence of the autonomic response pattern of cardiac deceleration and increased phasic electrodermal activity following true positives, false positives and false negatives errors, but not subsequent to true negative outcomes. Conclusions These findings suggest that there may be merit in complementing single-switch input with autonomic measurements to improve augmentative and alternative communications for pediatric access technology users. PMID:24607065

Autonomic responses to correct outcomes and interaction errors during single-switch scanning among children with severe spastic quadriplegic cerebral palsy.

PubMed

Leung, Brian; Chau, Tom

2014-03-08

The combination of single-switch access technology and scanning is the most promising means of augmentative and alternative communication for many children with severe physical disabilities. However, the physical impairment of the child and the technology's limited ability to interpret the child's intentions often lead to false positives and negatives (corresponding to accidental and missed selections, respectively) occurring at rates that frustrate the user and preclude functional communication. Multiple psychophysiological studies have associated cardiac deceleration and increased phasic electrodermal activity with self-realization of errors among able-bodied individuals. Thus, physiological measurements have potential utility at enhancing single-switch access, provided that such prototypical autonomic responses exist in persons with profound disabilities. The present case series investigated the autonomic responses of three pediatric single-switch users with severe spastic quadriplegic cerebral palsy, in the context of a single-switch letter matching activity. Each participant exhibited distinct autonomic responses to activity engagement. Our analysis confirmed the presence of the autonomic response pattern of cardiac deceleration and increased phasic electrodermal activity following true positives, false positives and false negatives errors, but not subsequent to true negative outcomes. These findings suggest that there may be merit in complementing single-switch input with autonomic measurements to improve augmentative and alternative communications for pediatric access technology users.

Frequency of false positive rapid HIV serologic tests in African men and women receiving PrEP for HIV prevention: implications for programmatic roll-out of biomedical interventions.

PubMed

Ndase, Patrick; Celum, Connie; Kidoguchi, Lara; Ronald, Allan; Fife, Kenneth H; Bukusi, Elizabeth; Donnell, Deborah; Baeten, Jared M

2015-01-01

Rapid HIV assays are the mainstay of HIV testing globally. Delivery of effective biomedical HIV prevention strategies such as antiretroviral pre-exposure prophylaxis (PrEP) requires periodic HIV testing. Because rapid tests have high (>95%) but imperfect specificity, they are expected to generate some false positive results. We assessed the frequency of true and false positive rapid results in the Partners PrEP Study, a randomized, placebo-controlled trial of PrEP. HIV testing was performed monthly using 2 rapid tests done in parallel with HIV enzyme immunoassay (EIA) confirmation following all positive rapid tests. A total of 99,009 monthly HIV tests were performed; 98,743 (99.7%) were dual-rapid HIV negative. Of the 266 visits with ≥1 positive rapid result, 99 (37.2%) had confirmatory positive EIA results (true positives), 155 (58.3%) had negative EIA results (false positives), and 12 (4.5%) had discordant EIA results. In the active PrEP arms, over two-thirds of visits with positive rapid test results were false positive results (69.2%, 110 of 159), although false positive results occurred at <1% (110/65,945) of total visits. When HIV prevalence or incidence is low due to effective HIV prevention interventions, rapid HIV tests result in a high number of false relative to true positive results, although the absolute number of false results will be low. Program roll-out for effective interventions should plan for quality assurance of HIV testing, mechanisms for confirmatory HIV testing, and counseling strategies for persons with positive rapid test results.

[Expression of epidermal growth factor receptor mutation specific antibodies in lung adenocarcinoma: evaluation of sensitivity, specificity and relationship to histologic subtypes].

PubMed

Lai, Y M; Feng, Q; Sun, Y; Wang, P; Shi, Y F; Zhao, M; Wu, Q; Li, X H

2016-09-08

To evaluate the expression of epidermal growth factor receptor (EGFR) mutation specific antibodies in invasive lung adenocarcinomas, and their sensitivity, specificity, as well as relationship to histological subtypes. Immunostaining with EGFR mutation-specific antibodies, del E746-A750 in exon 19 and L858R in exon 21, was performed in tissue microarrays of 884 cases of resection specimens to study the relationship between the immunophenotypes and morphologic subtypes. The sensitivity and specificity of the stains were compared with gene mutations detected by amplified refractory mutation system-polymerase chain reaction (ARMS-PCR). Of the 884 cases, the expression of del E746-A750 in exon 19 was 3+ , 2+ , 1+ and 0 in 7 cases (0.79%), 38 cases (4.30%), 129 cases (14.59%) and 710 cases (80.32%), respectively. For L858R in exon 21, 3+ , 2+ , 1+ and 0 staining were seen in 82 cases (9.28%), 93 cases (10.52%), 82 cases (9.28%) and 627 cases (70.93%), respectively. For both antibodies, positive expression (1+ or more) was mainly observed in lepidic, acinar and papillary predominant subtypes, and rarely seen in solid subtype or invasive mucinous adenocarcinoma (P=0.014 and 0.016). If 1+ to 3+ expression was set as positive, the specificity of exon 19/exon 21 reached 98.59%/92.98%, while the sensitivity was relatively lower (62.86%/88.89%). If 2+ to 3+ expression was read as positive, the specificity and sensitivity were 99.30%/97.37% and 25.71%/74.60% for exon 19/exon 21. If only 3+ expression was considered positive, the specificity was 100.0% for both antibodies, with a low sensitivity (8.57% for exon 19 and 34.92% for exon 21). Of the 18 cases with E746-A750 del in exon 19 based on molecular detection, the sensitivity of immunohistochemistry for exon 19 was 88.89% if a positive cutoff value ≥1+ was used; in contrast, of the 8 cases harboring other deletions in exon 19, only two cases were positive as 1+ . Both the EGFR mutation specific antibodies del E746-A750 in exon 19 and L858R in exon 21 demonstrate high specificity and relatively low sensitivity, and are mostly expressed in lepidic, acinar and papillary predominant subtypes, but rarely in solid subtype or invasive mucinous adenocarcinoma. For cases with 3+ expression, a mutational statue for EGFR is likely. For the 2+ positive cases, the accuracy to predict mutation almost reaches 90%, but molecular detection for confirmation is desirable. For the 1+ and negative cases, DNA-based test is essential to avoid false negativity.

Initial clinical laboratory experience in noninvasive prenatal testing for fetal aneuploidy from maternal plasma DNA samples.

PubMed

Futch, Tracy; Spinosa, John; Bhatt, Sucheta; de Feo, Eileen; Rava, Richard P; Sehnert, Amy J

2013-06-01

The aim of this study is to report the experience of noninvasive prenatal DNA testing using massively parallel sequencing in an accredited clinical laboratory. Laboratory information was examined for blood samples received for testing between February and November 2012 for chromosome 21 (Chr21), Chr18, and Chr13. Monosomy X (MX) testing was available from July 2012 for cystic hygroma indication. Outcomes were collected from providers on samples with positive results. There were 5974 samples tested, and results were issued within an average of 5.1 business days. Aneuploidy was detected in 284 (4.8%) samples (155 Chr21, 66 Chr18, 19 Chr13, 40 MX, and four double aneuploidy). Follow-ups are available for 245/284 (86%), and 77/284 (27.1%) are confirmed, including one double-aneuploidy case concordant with cytogenetics from maternal malignancy. Fourteen (0.2%) discordant (putative false-positive) results (one Chr21, six Chr18, three Chr13, three MX, and one Chr21/13) have been identified. Five (0.08%) false-negative cases are reported (two trisomy 21, two trisomy 18, and one MX). In 170 (2.8%) cases, the result for a single chromosome was indefinite. This report suggests that clinical testing of maternal cell-free DNA for fetal aneuploidy operates within performance parameters established in validation studies. Noninvasive prenatal testing is sensitive to biological contributions from placental and maternal sources. ©2013 Verinata Health, Inc. Prenatal Diagnosis published by John Wiley & Sons, Ltd.

Experimental investigation of observation error in anuran call surveys

USGS Publications Warehouse

McClintock, B.T.; Bailey, L.L.; Pollock, K.H.; Simons, T.R.

2010-01-01

Occupancy models that account for imperfect detection are often used to monitor anuran and songbird species occurrence. However, presenceabsence data arising from auditory detections may be more prone to observation error (e.g., false-positive detections) than are sampling approaches utilizing physical captures or sightings of individuals. We conducted realistic, replicated field experiments using a remote broadcasting system to simulate simple anuran call surveys and to investigate potential factors affecting observation error in these studies. Distance, time, ambient noise, and observer abilities were the most important factors explaining false-negative detections. Distance and observer ability were the best overall predictors of false-positive errors, but ambient noise and competing species also affected error rates for some species. False-positive errors made up 5 of all positive detections, with individual observers exhibiting false-positive rates between 0.5 and 14. Previous research suggests false-positive errors of these magnitudes would induce substantial positive biases in standard estimators of species occurrence, and we recommend practices to mitigate for false positives when developing occupancy monitoring protocols that rely on auditory detections. These recommendations include additional observer training, limiting the number of target species, and establishing distance and ambient noise thresholds during surveys. ?? 2010 The Wildlife Society.

Enhanced HTS hit selection via a local hit rate analysis.

PubMed

Posner, Bruce A; Xi, Hualin; Mills, James E J

2009-10-01

The postprocessing of high-throughput screening (HTS) results is complicated by the occurrence of false positives (inactive compounds misidentified as active by the primary screen) and false negatives (active compounds misidentified as inactive by the primary screen). An activity cutoff is frequently used to select "active" compounds from HTS data; however, this approach is insensitive to both false positives and false negatives. An alternative method that can minimize the occurrence of these artifacts will increase the efficiency of hit selection and therefore lead discovery. In this work, rather than merely using the activity of a given compound, we look at the presence and absence of activity among all compounds in its "chemical space neighborhood" to give a degree of confidence in its activity. We demonstrate that this local hit rate (LHR) analysis method outperforms hit selection based on ranking by primary screen activity values across ten diverse high throughput screens, spanning both cell-based and biochemical assay formats of varying biology and robustness. On average, the local hit rate analysis method was approximately 2.3-fold and approximately 1.3-fold more effective in identifying active compounds and active chemical series, respectively, than selection based on primary activity alone. Moreover, when applied to finding false negatives, this method was 2.3-fold better than ranking by primary activity alone. In most cases, novel hit series were identified that would have otherwise been missed. Additional uses of and observations regarding this HTS analysis approach are also discussed.

Human versus automation in responding to failures: an expected-value analysis

NASA Technical Reports Server (NTRS)

Sheridan, T. B.; Parasuraman, R.

2000-01-01

A simple analytical criterion is provided for deciding whether a human or automation is best for a failure detection task. The method is based on expected-value decision theory in much the same way as is signal detection. It requires specification of the probabilities of misses (false negatives) and false alarms (false positives) for both human and automation being considered, as well as factors independent of the choice--namely, costs and benefits of incorrect and correct decisions as well as the prior probability of failure. The method can also serve as a basis for comparing different modes of automation. Some limiting cases of application are discussed, as are some decision criteria other than expected value. Actual or potential applications include the design and evaluation of any system in which either humans or automation are being considered.

Dark energy, scalar singlet dark matter and the Higgs portal

NASA Astrophysics Data System (ADS)

Landim, Ricardo G.

2018-05-01

One of the simplest extensions of the Standard Model (SM) comprises the inclusion of a massive real scalar field, neutral under the SM gauge groups, to be a dark matter candidate. The addition of a dimension-six term into the potential of the scalar dark matter enables the appearance of a false vacuum that describes the cosmic acceleration. We show that the running of the singlet self-interaction and the Higgs portal coupling differs from the standard scalar singlet dark matter model. If we maintain a positive quartic coupling, it is also possible to describe the accelerated expansion of the Universe through a false vacuum with the addition of a dimension-eight interaction term. In this case, where the potential remains bounded from below at low energies, the false vacuum decay is highly suppressed.

Memory for media: investigation of false memories for negatively and positively charged public events.

PubMed

Porter, Stephen; Taylor, Kristian; Ten Brinke, Leanne

2008-01-01

Despite a large body of false memory research, little has addressed the potential influence of an event's emotional content on susceptibility to false recollections. The Paradoxical Negative Emotion (PNE) hypothesis predicts that negative emotion generally facilitates memory but also heightens susceptibility to false memories. Participants were asked whether they could recall 20 "widely publicised" public events (half fictitious) ranging in emotional valence, with or without visual cues. Participants recalled a greater number of true negative events (M=3.31/5) than true positive (M=2.61/5) events. Nearly everyone (95%) came to recall at least one false event (M=2.15 false events recalled). Further, more than twice as many participants recalled any false negative (90%) compared to false positive (41.7%) events. Negative events, in general, were associated with more detailed memories and false negative event memories were more detailed than false positive event memories. Higher dissociation scores were associated with false recollections of negative events, specifically.

Residual risk of bacterial contamination of platelets: six years of experience with sterility testing.

PubMed

Ramirez-Arcos, Sandra; DiFranco, Caesar; McIntyre, Terri; Goldman, Mindy

2017-09-01

Canadian Blood Services screens 100% of platelet concentrates (PCs) for bacterial contamination with the BacT/ALERT system. Quality-control sterility testing of 1% (≥10 units) of outdated PCs is performed monthly. Data from routine screening, quality-control testing, and septic reactions obtained from 2010 to 2016 are presented herein. In total, 601,988 buffy coat PC pools and 186,737 apheresis PCs were routinely screened with aerobic cultures over 6 years. Outdate quality-control testing of 8535 buffy coat and 8498 apheresis PCs was performed using aerobic and anaerobic cultures during the same period. Results were classified as "true-positives" when the same bacterium was isolated in initial and confirmatory cultures or "false-negatives" when bacteria were missed in early screening and were captured during quality-control sterility testing or through investigation of sepsis cases. During routine screening, the true-positive rates between buffy coat (0.94 per 10,000) and apheresis (0.96 per 10,000) PCs were similar (p = 0.9473). Seventy-five bacteria isolated during PC screening included Gram-positive and Gram-negative organisms. Six false-negative septic reactions were reported that implicated coagulase-negative staphylococci (n = 3) and Staphylococcus aureus (n = 3) for approximate rates of 1 per 100,000 transfusion reactions and 1 per 500,000 fatalities. During quality-control testing, the false-negative rates between buffy coat (8 per 10,000) and apheresis (9 per 10,000) PCs were similar (p = 0.7897). All 15 quality-control isolates were Gram-positive bacteria. The current bacterial screening protocol is efficacious for identifying Gram-negative bacteria. However, the high proportion of Gram-positive organisms detected on outdate quality-control testing and septic transfusion events demonstrates a residual safety risk that merits further intervention. © 2017 AABB.

Performance of two strategies for urgent ANCA and anti-GBM analysis in vasculitis.

PubMed

de Joode, Anoek A E; Roozendaal, Caroline; van der Leij, Marcel J; Bungener, Laura B; Sanders, Jan Stephan F; Stegeman, Coen A

2014-02-01

In anti-neutrophil cytoplasmic antibodies (ANCA) associated small vessel vasculitis (AAV), rapid testing for ANCA and anti-glomerular basement membrane (GBM) antibodies may be beneficial for therapeutic purpose. We analysed the diagnostic performance of two rapid ANCA and anti-GBM test methods in 260 patients with suspected AAV. Between January 2004 and November 2010, we analysed 260 samples by qualitative Dotblot (Biomedical Diagnostics); retrospective analysis followed with directly coated highly sensitive automated Phadia ELiA and ELiA anti-GBM. Results were related to the final clinical diagnosis and compared with routine capture ELISA. Seventy-four patients had a final diagnosis of AAV (n=62) or anti-GBM disease (n=12). Both Dotblot and ELiA detected all 12 cases of anti-GBM disease; 2 false positive results were found. Dotblot detected ANCA in 56 of 62 AAV patients (sensitivity 90%, NPV 97%), and showed 5 false positives (specificity 97%, PPV 90%). The Phadia ELiA anti-PR3(s) or anti-MPO(s) was positive in 57 of 62 AAV patients (sensitivity 92%, NPV 97%), and had 5 false positives (specificity 97%, PPV 88%). Routine capture ELISA was equally accurate (sensitivity 94%, specificity 97%, PPV 88%, NPV 98%). The Dotblot and Phadia ELiA on anti-GBM, anti-PR3(s) and anti-MPO(s) performed excellently; results were almost identical to routine ELISA. When suspicion of AAV or anti-GBM disease is high and diagnosis is urgently needed, both tests are very powerful for rapid serological diagnosis. Further studies have to confirm the test performances in samples routinely presented for ANCA testing and in follow-up of positive patients. Copyright © 2013 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

Heterophile antibody interference in qualitative urine/serum hCG devices: Case report.

PubMed

Patel, Khushbu K; Gronowski, Ann M

2016-06-01

This case report investigates the origin of a false positive result on a serum qualitative human chorionic gonadotropin (hCG) device. A 46-year-old woman diagnosed with chronic myeloid leukemia presented with nausea and vomiting. A qualitative serum hCG test was interpreted as positive; however, a quantitative serum hCG test was negative (<5IU/L). To further investigate this discrepancy, the sample was pretreated with heterophilic blocking reagent (HBR). Additionally, the sample was tested on other qualitative hCG devices composed of antibodies from different animal sources. Blocking reagent from an automated quantitative immunoassay was also tested for its ability to inhibit the heterophile antibody interference. The qualitative test result was negative after pretreatment with heterophilic blocking reagent. Other devices composed of antibodies from different animal sources also demonstrated mixed results with the patient's sample. Blocking reagent obtained from the automated quantitative assay inhibited the heterophile antibody interference in the patient's sample. This case demonstrates that positive serum point-of-care hCG results should be interpreted with caution and confirmed with a quantitative serum hCG immunoassay when clinical suspicion is raised. Copyright © 2016 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Tumor Burden Analysis on Computed Tomography by Automated Liver and Tumor Segmentation

PubMed Central

Linguraru, Marius George; Richbourg, William J.; Liu, Jianfei; Watt, Jeremy M.; Pamulapati, Vivek; Wang, Shijun; Summers, Ronald M.

2013-01-01

The paper presents the automated computation of hepatic tumor burden from abdominal CT images of diseased populations with images with inconsistent enhancement. The automated segmentation of livers is addressed first. A novel three-dimensional (3D) affine invariant shape parameterization is employed to compare local shape across organs. By generating a regular sampling of the organ's surface, this parameterization can be effectively used to compare features of a set of closed 3D surfaces point-to-point, while avoiding common problems with the parameterization of concave surfaces. From an initial segmentation of the livers, the areas of atypical local shape are determined using training sets. A geodesic active contour corrects locally the segmentations of the livers in abnormal images. Graph cuts segment the hepatic tumors using shape and enhancement constraints. Liver segmentation errors are reduced significantly and all tumors are detected. Finally, support vector machines and feature selection are employed to reduce the number of false tumor detections. The tumor detection true position fraction of 100% is achieved at 2.3 false positives/case and the tumor burden is estimated with 0.9% error. Results from the test data demonstrate the method's robustness to analyze livers from difficult clinical cases to allow the temporal monitoring of patients with hepatic cancer. PMID:22893379

Generalized site occupancy models allowing for false positive and false negative errors

USGS Publications Warehouse

Royle, J. Andrew; Link, W.A.

2006-01-01

Site occupancy models have been developed that allow for imperfect species detection or ?false negative? observations. Such models have become widely adopted in surveys of many taxa. The most fundamental assumption underlying these models is that ?false positive? errors are not possible. That is, one cannot detect a species where it does not occur. However, such errors are possible in many sampling situations for a number of reasons, and even low false positive error rates can induce extreme bias in estimates of site occupancy when they are not accounted for. In this paper, we develop a model for site occupancy that allows for both false negative and false positive error rates. This model can be represented as a two-component finite mixture model and can be easily fitted using freely available software. We provide an analysis of avian survey data using the proposed model and present results of a brief simulation study evaluating the performance of the maximum-likelihood estimator and the naive estimator in the presence of false positive errors.

Comparison between point-of-care dermatophyte test medium and mycology laboratory culture for diagnosis of dermatophytosis in dogs and cats.

PubMed

Kaufmann, Ronnie; Blum, Shlomo E; Elad, Daniel; Zur, Gila

2016-08-01

Point-of-care Dermatophyte Test Medium (PoC-DTM) is a diagnostic procedure to rule in/rule out dermatophytosis in veterinary clinics. To evaluate the performance of PoC-DTM in the clinic compared to DTM plate culture in a mycology laboratory and to compare results obtained by general practitioners and referral clinicians. Hair samples were collected from 47 cats and 54 dogs with suspected dermatophytosis and from nine healthy controls (seven cats and two dogs). This was a multicentre blinded study. In one group (65 suspected cases, 9 healthy controls), PoC-DTM results were evaluated by clinicians in a referral clinic (SP group) who examined the colony morphology macroscopically and microscopically. In the other group (36 suspected cases) PoC-DTM results were evaluated by clinicians from general practice for colour change only, with no macroscopic or microscopic examination (GP group). All hair samples were also cultured on DTM plates in a mycology laboratory. Laboratory culture was considered the gold standard for comparison. Agreements between tests were 97% (two false positive; κ = 0.839) and 80.6% (five false positives and two false negatives; κ = 0.466) in the SP and GP groups, respectively. This difference between groups was significant (P = 0.024). When applying macroscopic and microscopic evaluation of the colony, PoC-DTM is accurate for diagnosing dermatophytes with only a 3% chance of error. However, when macroscopic and microscopic examination is not included there is significant (19.4%) chance for an incorrect diagnosis. © 2016 ESVD and ACVD.

[Non-palpable breast cancer malignant on needle core biopsy and no malignancy in surgical excision: how to manage?].

PubMed

Cheurfa, N; Giard, S

2015-01-01

Despite the standard management of non-palpable breast cancer (needle core biopsy diagnostic, accurate preoperative localization), there are differences in some cases between the malignant histo-pathological finding in diagnostic biopsy results and negative histo-pathological finding after surgical excision. The aim of this study is to evaluate this incidence and classifying them under three category: failure of surgical excision after preoperative identification; removal of the tumor was already completed by percutaneous biopsy; percutaneous biopsy true false positive. We conducted a study based on prospective database, all patients included in this study had partial mastectomy for ductal carcinoma in-situ or invasive cancer which was diagnosed by needle core biopsy and normal/benign after surgery. Regarding the partial mastectomy, 1863 was performed in the last three years in our center. Thirty-seven patients (2%) correspond our study criteria. After discussion of cases in our multidisciplinary reunion, 6 patients (16%) were considered as failure of surgical excision, 26 patients (70%) as true removal of the whole lesion in the core, and 5 patients (13%) as true false-positive cores. This is the first study witch investigate all factors that influence the results of negative final histo-pathological finding of surgical excision of the tumor after malignant diagnostic needle core biopsy. This rare situation need a multidisciplinary meeting to analyse all the steps of management and to determine causes of those false results and try to find adequate management to solve this problem. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Validity of combined cytology and human papillomavirus (HPV) genotyping with adjuvant DNA-cytometry in routine cervical screening: results from 31031 women from the Bonn-region in West Germany.

PubMed

Bollmann, Reinhard; Bankfalvi, Agnes; Griefingholt, Harald; Trosic, Ante; Speich, Norbert; Schmitt, Christoph; Bollmann, Magdolna

2005-05-01

Our aim was to improve the accuracy of routine cervical screening by a risk-adapted multimodal protocol with special focus on possible reduction and prognostic assessment of false positive results. A cohort of 31031 women from the Bonn-region in West Germany, median age 36 years, were screened by cytology (conventional or liquid-based), followed by PCR-based HVP detection with genotyping and adjuvant DNA image cytometry, if indicated, in a sequential manner. The true prevalence of high-grade cervical intraepithelial neoplasia and carcinoma (>/=CIN2) was 0.32% in the population as projected from cervical biopsies of 123 women (0.4%), of whom 100 showed >/=CIN2. Sensitivity of the cytology screening program at PapIIID/HSIL threshold for detecting histologically confirmed >/=CIN2 cases was 81%, with specificity, positive predictive value (PPV) and negative predictive value (NPV) of 99, 20.9 and 99.9%, respectively. Of 38 women receiving the complete screening protocol, all the 31 >/=CIN2 cases were correctly detected by cytology alone, 30 by positive high-risk HPV genotype and 30 by aneuploid DNA profile. The combination of the three methods resulted in an up to 6.9% increase in PPV for >/=CIN2 at practically unchanged detection rate with the additional benefit of being able to predict the probable outcome of CIN1 lesions detected as false positives with any single test. Multimodal cervical screening might permit identification of those women with low-grade squamous intraepithelial lesions likely to progress at an earlier and curable stage of disease and lengthen the screening interval in those with transient minor lesions caused by productive HPV infection.

Improving the performance of lesion-based computer-aided detection schemes of breast masses using a case-based adaptive cueing method

NASA Astrophysics Data System (ADS)

Tan, Maxine; Aghaei, Faranak; Wang, Yunzhi; Qian, Wei; Zheng, Bin

2016-03-01

Current commercialized CAD schemes have high false-positive (FP) detection rates and also have high correlations in positive lesion detection with radiologists. Thus, we recently investigated a new approach to improve the efficacy of applying CAD to assist radiologists in reading and interpreting screening mammograms. Namely, we developed a new global feature based CAD approach/scheme that can cue the warning sign on the cases with high risk of being positive. In this study, we investigate the possibility of fusing global feature or case-based scores with the local or lesion-based CAD scores using an adaptive cueing method. We hypothesize that the information from the global feature extraction (features extracted from the whole breast regions) are different from and can provide supplementary information to the locally-extracted features (computed from the segmented lesion regions only). On a large and diverse full-field digital mammography (FFDM) testing dataset with 785 cases (347 negative and 438 cancer cases with masses only), we ran our lesion-based and case-based CAD schemes "as is" on the whole dataset. To assess the supplementary information provided by the global features, we used an adaptive cueing method to adaptively adjust the original CAD-generated detection scores (Sorg) of a detected suspicious mass region based on the computed case-based score (Scase) of the case associated with this detected region. Using the adaptive cueing method, better sensitivity results were obtained at lower FP rates (<= 1 FP per image). Namely, increases of sensitivities (in the FROC curves) of up to 6.7% and 8.2% were obtained for the ROI and Case-based results, respectively.

False-positive alarms for bacterial screening of platelet concentrates with BacT/ALERT new-generation plastic bottles: a multicenter pilot study.

PubMed

Hundhausen, T; Müller, T H

2005-08-01

The microbial detection system BacT/ALERT (bioMérieux) is widely used to monitor bacterial contamination of platelet concentrates (PCs). Recently, the manufacturer introduced polycarbonate culture bottles and a modified pH-sensitive liquid emulsion sensor as microbial growth indicator. This reconfigured assay was investigated in a routine setting. In each of eight transfusion centers, samples from 500 consecutive PCs were monitored for 1 week. For all PCs with a positive BacT/ALERT signal, retained samples and, if available, original PC containers and concomitant red blood cell concentrates were analyzed independently. Initially BacT/ALERT-positive PCs without bacterial identification in any sample were defined as false-positive. BacT/ALERT-positive PCs with bacteria in the first sample only were called potentially positive. PCs with bacteria in the first sample and the same strain in at least one additional sample were accepted as positive. Five PCs (0.13%) were positive, 9 PCs (0.23%) were potentially positive, and 35 PCs (0.9%) were false-positive. The rate of false-positive BacT/ALERT results varied substantially between centers (<0.2%-3.2%). Tracings from false-positive cultures lacked an exponential increase of the signal during incubation. Most of these false-positives were due to malfunctioning cells in various BacT/ALERT incubation units. Careful assessment of individual tracings of samples with positive signals helps to identify malfunctioning incubation units. Their early shutdown or replacement minimizes the high rate of unrectifiable product rejects attributed to false-positive alarms and avoids unnecessary concern of doctors and patients after conversion to a reconfigured BacT/ALERT assay.

Highly sensitive detection of individual HEAT and ARM repeats with HHpred and COACH.

PubMed

Kippert, Fred; Gerloff, Dietlind L

2009-09-24

HEAT and ARM repeats occur in a large number of eukaryotic proteins. As these repeats are often highly diverged, the prediction of HEAT or ARM domains can be challenging. Except for the most clear-cut cases, identification at the individual repeat level is indispensable, in particular for determining domain boundaries. However, methods using single sequence queries do not have the sensitivity required to deal with more divergent repeats and, when applied to proteins with known structures, in some cases failed to detect a single repeat. Testing algorithms which use multiple sequence alignments as queries, we found two of them, HHpred and COACH, to detect HEAT and ARM repeats with greatly enhanced sensitivity. Calibration against experimentally determined structures suggests the use of three score classes with increasing confidence in the prediction, and prediction thresholds for each method. When we applied a new protocol using both HHpred and COACH to these structures, it detected 82% of HEAT repeats and 90% of ARM repeats, with the minimum for a given protein of 57% for HEAT repeats and 60% for ARM repeats. Application to bona fide HEAT and ARM proteins or domains indicated that similar numbers can be expected for the full complement of HEAT/ARM proteins. A systematic screen of the Protein Data Bank for false positive hits revealed their number to be low, in particular for ARM repeats. Double false positive hits for a given protein were rare for HEAT and not at all observed for ARM repeats. In combination with fold prediction and consistency checking (multiple sequence alignments, secondary structure prediction, and position analysis), repeat prediction with the new HHpred/COACH protocol dramatically improves prediction in the twilight zone of fold prediction methods, as well as the delineation of HEAT/ARM domain boundaries. A protocol is presented for the identification of individual HEAT or ARM repeats which is straightforward to implement. It provides high sensitivity at a low false positive rate and will therefore greatly enhance the accuracy of predictions of HEAT and ARM domains.

Highly Sensitive Detection of Individual HEAT and ARM Repeats with HHpred and COACH

PubMed Central

Kippert, Fred; Gerloff, Dietlind L.

2009-01-01

Background HEAT and ARM repeats occur in a large number of eukaryotic proteins. As these repeats are often highly diverged, the prediction of HEAT or ARM domains can be challenging. Except for the most clear-cut cases, identification at the individual repeat level is indispensable, in particular for determining domain boundaries. However, methods using single sequence queries do not have the sensitivity required to deal with more divergent repeats and, when applied to proteins with known structures, in some cases failed to detect a single repeat. Methodology and Principal Findings Testing algorithms which use multiple sequence alignments as queries, we found two of them, HHpred and COACH, to detect HEAT and ARM repeats with greatly enhanced sensitivity. Calibration against experimentally determined structures suggests the use of three score classes with increasing confidence in the prediction, and prediction thresholds for each method. When we applied a new protocol using both HHpred and COACH to these structures, it detected 82% of HEAT repeats and 90% of ARM repeats, with the minimum for a given protein of 57% for HEAT repeats and 60% for ARM repeats. Application to bona fide HEAT and ARM proteins or domains indicated that similar numbers can be expected for the full complement of HEAT/ARM proteins. A systematic screen of the Protein Data Bank for false positive hits revealed their number to be low, in particular for ARM repeats. Double false positive hits for a given protein were rare for HEAT and not at all observed for ARM repeats. In combination with fold prediction and consistency checking (multiple sequence alignments, secondary structure prediction, and position analysis), repeat prediction with the new HHpred/COACH protocol dramatically improves prediction in the twilight zone of fold prediction methods, as well as the delineation of HEAT/ARM domain boundaries. Significance A protocol is presented for the identification of individual HEAT or ARM repeats which is straightforward to implement. It provides high sensitivity at a low false positive rate and will therefore greatly enhance the accuracy of predictions of HEAT and ARM domains. PMID:19777061

SU-E-T-472: Improvement of IMRT QA Passing Rate by Correcting Angular Dependence of MatriXX

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Q; Watkins, W; Kim, T

2015-06-15

Purpose: Multi-channel planar detector arrays utilized for IMRT-QA, such as the MatriXX, exhibit an incident-beam angular dependent response which can Result in false-positive gamma-based QA results, especially for helical tomotherapy plans which encompass the full range of beam angles. Although MatriXX can use with gantry angle sensor to provide automatically angular correction, this sensor does not work with tomotherapy. The purpose of the study is to reduce IMRT-QA false-positives by correcting for the MatriXX angular dependence. Methods: MatriXX angular dependence was characterized by comparing multiple fixed-angle irradiation measurements with corresponding TPS computed doses. For 81 Tomo-helical IMRT-QA measurements, two differentmore » correction schemes were tested: (1) A Monte-Carlo dose engine was used to compute MatriXX signal based on the angular-response curve. The computed signal was then compared with measurement. (2) Uncorrected computed signal was compared with measurements uniformly scaled to account for the average angular dependence. Three scaling factor (+2%, +2.5%, +3%) were tested. Results: The MatriXX response is 8% less than predicted for a PA beam even when the couch is fully accounted for. Without angular correction, only 67% of the cases pass the >90% points γ<1 (3%, 3mm). After full angular correction, 96% of the cases pass the criteria. Of three scaling factors, +2% gave the highest passing rate (89%), which is still less than the full angular correction method. With a stricter γ(2%,3mm) criteria, the full angular correction method was still able to achieve the 90% passing rate while the scaling method only gives 53% passing rate. Conclusion: Correction for the MatriXX angular dependence reduced the false-positives rate of our IMRT-QA process. It is necessary to correct for the angular dependence to achieve the IMRT passing criteria specified in TG129.« less

Ranking metrics in gene set enrichment analysis: do they matter?

PubMed

Zyla, Joanna; Marczyk, Michal; Weiner, January; Polanska, Joanna

2017-05-12

There exist many methods for describing the complex relation between changes of gene expression in molecular pathways or gene ontologies under different experimental conditions. Among them, Gene Set Enrichment Analysis seems to be one of the most commonly used (over 10,000 citations). An important parameter, which could affect the final result, is the choice of a metric for the ranking of genes. Applying a default ranking metric may lead to poor results. In this work 28 benchmark data sets were used to evaluate the sensitivity and false positive rate of gene set analysis for 16 different ranking metrics including new proposals. Furthermore, the robustness of the chosen methods to sample size was tested. Using k-means clustering algorithm a group of four metrics with the highest performance in terms of overall sensitivity, overall false positive rate and computational load was established i.e. absolute value of Moderated Welch Test statistic, Minimum Significant Difference, absolute value of Signal-To-Noise ratio and Baumgartner-Weiss-Schindler test statistic. In case of false positive rate estimation, all selected ranking metrics were robust with respect to sample size. In case of sensitivity, the absolute value of Moderated Welch Test statistic and absolute value of Signal-To-Noise ratio gave stable results, while Baumgartner-Weiss-Schindler and Minimum Significant Difference showed better results for larger sample size. Finally, the Gene Set Enrichment Analysis method with all tested ranking metrics was parallelised and implemented in MATLAB, and is available at https://github.com/ZAEDPolSl/MrGSEA . Choosing a ranking metric in Gene Set Enrichment Analysis has critical impact on results of pathway enrichment analysis. The absolute value of Moderated Welch Test has the best overall sensitivity and Minimum Significant Difference has the best overall specificity of gene set analysis. When the number of non-normally distributed genes is high, using Baumgartner-Weiss-Schindler test statistic gives better outcomes. Also, it finds more enriched pathways than other tested metrics, which may induce new biological discoveries.

External quality assessment program for detection of glucose-6-phosphate dehydrogenase deficiency in the Guangxi region.

PubMed

Tang, Juan; Zhou, Xiangyang; Liu, Xiaochun; Ning, Leping; Zhou, Weiya; He, Yi

2017-09-01

The aim of this study is to improve the quality of testing for glucose-6-phosphate dehydrogenase (G6PD) deficiency through evaluation and analysis of the laboratory tests for G6PD activity. External quality assessment (EQA) was carried out twice per year with five samples each from 2014 to 2016. Samples were used for quantitative and qualitative assays. Quantitative results were collected, qualitative results were determined with reference values, and information about methods, reagents and instruments from participating laboratories within the required time. Laboratory performance scores, coefficient of variation (CV), and the rates of false negative and positive results were calculated. As a result, a total of 2,834 cases of negative quality control (QC) samples and 2,451 cases of positive QC samples were assessed, where the rates of false negative and false positive results were 1.31% (37/2,834) and 1.34% (33/2,451), respectively. Quantitative results indicated an increasing trend in testing quality, which were consistent with conclusions based on the comparison of EQA full-score and acceptable ratio in six assessments. The 2nd assay in 2016 had the best full-score ratio of 68.9% (135/196) and best acceptable ratio of 84.2% (165/196). There was a decreasing trend in the average CV of six reagents produced in China, and the range of average CV increased to 14.6-23.6% in 2016. The average CV of low level and high level samples was 22.5% and 15.3%, respectively, demonstrating that samples with low G6PD activity have greater interlaboratory CV values. In conclusion, laboratories improved their testing quality and provided better diagnostic service for G6PD deficiency in areas with high incidence after participation in the EQA program in the Guangxi region.

Microscopic diagnosis of dysbacteriosis in stained vaginal smears in clinical practice.

PubMed

Verbruggen, Banut-Sabine M; Boon, Mathilde E; Melkerl, Peter; van Haaften, Maarten; Heintz, A Peter M

2006-10-01

Dysbacteriosis is a microscopical diagnosis. In women with dysbacteriosis, an overgrowth of coccoid bacteria and almost a complete absence of lactobacilli are observed in the (stained) vaginal smear. The aim of this study was to determine the accuracy of this microscopic diagnosis in clinical practice. The analysis concerned 342 consecutive cases in which the microscopy of the stained smears was performed by general practitioners trained in diagnosing dysbacteriosis. These smears were sent to the pathologist for confirmation of the microscopical diagnosis of the clinician. The cytological diagnoses of the pathologist, sometimes performed on restained slides when the quality of the staining was substandard, were considered as the "gold standard." In 92 of the 342 cases, dysbacteriosis was unequivocally established by the pathologist. Sensitivity and specificity of the microscopical diagnoses of the clinicians were 40% and 85%, respectively. There were 37 false-positive and 54 false-negative diagnoses of dysbacteriosis rendered by the clinicians. The most frequent reason for a false-negative diagnosis was an excess of lactobacilli in the smear. This study shows that even in stained smears it is difficult for clinicians to render a correct evaluation of the status of the vaginal flora.

Importance of the autocontrol crossmatch in human renal transplantation.

PubMed

Cross, D E; Greiner, R; Whittier, F C

1976-04-01

The killing of donor cells in the standard lymphocyte crossmatch is considered strong evidence for preformed antibodies in the recipients's serum. Moreover, it is generally accepted that presensitization has occurred if any of the stored sera kill the donor cells. In our hands, if either the current or the stored sera kill the donor cells, it precludes transplantation. In nine cases we discovered that the recipient's sera also killed the recipient's own lymphocytes, a positive autocontrol test, indicating that factors other than conventional preformed cytotoxic antibodies were responsible for the positive standard crossmatch. The nine patients who demonstrated a positive standard crossmatch and a positive autocontrol for those sera received cadaver allografts. None of the kidneys were rejected hyperacutely and all are functioning adequately. We conclude that the autocontrol crossmatch is an important adjunct for uncovering false positive reactions in the standard lymphocyte crossmatch test.

Should fine needle aspiration biopsy be the first pathological investigation in the diagnosis of a bone lesion? An algorithmic approach with review of literature

PubMed Central

Mehrotra, Ravi; Singh, Mamta; Singh, Premala A; Mannan, Rahul; Ojha, Vinod K; Singh, Pradumyn

2007-01-01

Background Fine needle aspiration biopsy (FNAB) is gaining increasing popularity in the diagnosis of musculoskeletal lesions; and in many patients, a definitive diagnosis can be rendered from aspiration smears alone. Its applicability in bone pathology, however, has been controversial due to a high percentage of inadequate smears, difficulty in evaluation of tissue architecture and nonspecific results in the diagnosis of primary bone lesions. In this study, the value of aspiration as the first pathological investigation in the diagnosis of a bone lesion was evaluated. Methods 91 cases of clinically suspected cases of bone lesions were aspirated over a period of two years. Direct or cytospin smears were fixed in 95% alcohol and stained by Hematoxylin and Eosin or air-dried and later fixed in methanol for May Grŭnwald Giemsa staining. Results Of the 91 patients who were subjected to FNAB, 81 were considered satisfactory and 10.9 % (10) were inadequate\\inconclusive for diagnosis. Cyto-histological concordance was obtained in 78.5 % (51/65) patients. Positive and negative predictive values were 87.5% and 97.2 % respectively. Sensitivity as a preliminary diagnostic technique was 93.3%, whereas specificity was 94.5 %. Overall, diagnostic accuracy was 94.2 %. Metastatic lesions were detected with 100% accuracy. Two cases were reported as false positive and one case as false negative. Conclusion Cytology provides valuable information to the clinician to make an informed decision regarding appropriate therapy. We conclude that time-consuming and costly investigations may be reduced by choosing FNAB as the initial pathological diagnostic method for skeletal lesions of unknown origin. The choice of radiological examinations, laboratory tests and surgical biopsies can be determined after the FNAB diagnosis. PMID:17439659

Clinical and molecular profile of newborns with confirmed or suspicious congenital adrenal hyperplasia detected after a public screening program implementation.

PubMed

Kopacek, Cristiane; Prado, Mayara J; da Silva, Claudia M D; de Castro, Simone M; Beltrão, Luciana A; Vargas, Paula R; Grandi, Tarciana; Rossetti, Maria L R; Spritzer, Poli Mara

2018-04-30

To describe the results obtained in a neonatal screening program after its implementation and to assess the clinical and molecular profiles of confirmed and suspicious congenital adrenal hyperplasia cases. A cross-sectional study was conducted. Newborns with suspected disease due to high 17-hydroxyprogesterone levels and adjusted for birth weight were selected. Classical congenital adrenal hyperplasia (salt-wasting and simple virilizing forms) was diagnosed by an increase in 17-hydroxyprogesterone levels as confirmed in the retest, clinical evaluation, and genotype determined by SNaPshot and multiplex ligation-dependent probe amplification. After 24 months, 15 classic congenital adrenal hyperplasia cases were diagnosed in a total of 217,965 newborns, with an estimated incidence of 1:14,531. From 132 patients, seven non-classical and 14 heterozygous patients were screened for CYP21A2 mutations, and 96 patients presented false positives with wild type CYP21A2. On retest, increased 17-hydroxyprogesterone levels were found in classical congenital adrenal hyperplasia patients and showed significant correlation with genotype-related classical genital adrenal hyperplasia. The most frequent mutations were IVS2-13A/C>G followed by gene deletion or rearrangement events in the classical form. In non-classical and heterozygous diseases, p.Val282Leu was the most common mutation. The results underscore the effectiveness of congenital adrenal hyperplasia neonatal screening in the public health system and indicate that the adopted strategy was appropriate. The second sample collection along with genotyping of suspected cases helped to properly diagnose both severe and milder cases and delineate them from false positive patients. Copyright © 2018. Published by Elsevier Editora Ltda.

Sestamibi technetium-99m brain single-photon emission computed tomography to identify recurrent glioma in adults: 201 studies.

PubMed

Le Jeune, Florence Prigent; Dubois, François; Blond, Serge; Steinling, Marc

2006-04-01

In the follow-up of treated gliomas, CT and MRI can often not differentiate radionecrosis from recurrent tumor. The aim of this study was to assess the interest of functional imaging with (99m)Tc-MIBI SPECT in a large series of 201 examinations. MIBI SPECT were performed in 81 patients treated for brain gliomas. A MIBI uptake index was computed as the ratio of counts in the lesion to counts in the controlateral region. SPECT was compared to stereotactic biopsy in 14 cases, or in the others cases to imaging evolution or clinical course at 6 months after the last tomoscintigraphy Two hundred and one tomoscintigraphies were performed. One hundred and two scans were true positive, 82 scans were true negative. Six scans were false positive (corresponding to 3 patients): 2 patients with an inflammatory reaction after radiosurgery, 1 with no explanation up to now. Eleven scans were false negative (5 patients): 1 patient with a deep peri-ventricular lesion, 2 patients with no contrast enhancement on MRI, 2 patients with a temporal tumor. The sensitivity for tumor recurrence was 90%, specificity 91.5% and accuracy 90.5%. We studied separately low and high grade glioma: sensitivity for tumor recurrence was respectively 91% and 89%, specificity 100% and 83% and accuracy 95% and 87%. MIBI SPECT allowed the diagnose of anaplasic degenerence of low grade sometimes earlier than clinical (5 cases) or MRI signs (7 cases). Our results confirm the usefullness of MIBI SPECT in the follow-up of treated gliomas for the differential diagnosis between radiation necrosis and tumor recurrence.

Is there a positive bias in false recognition? Evidence from confabulating amnesia patients.

PubMed

Alkathiri, Nura H; Morris, Robin G; Kopelman, Michael D

2015-10-01

Although there is some evidence for a positive emotional bias in the content of confabulations in brain damaged patients, findings have been inconsistent. The present study used the semantic-associates procedure to induce false recall and false recognition in order to examine whether a positive bias would be found in confabulating amnesic patients, relative to non-confabulating amnesic patients and healthy controls. Lists of positive, negative and neutral words were presented in order to induce false recall or false recognition of non-presented (but semantically associated) words. The latter were termed 'critical intrusions'. Thirteen confabulating amnesic patients, 13 non-confabulating amnesic patients and 13 healthy controls were investigated. Confabulating patients falsely recognised a higher proportion of positive (but unrelated) words, compared with non-confabulating patients and healthy controls. No differences were found for recall memory. Signal detection analysis, however, indicated that the positive bias for false recognition memory might reflect weaker memory in the confabulating amnesic group. This suggested that amnesia patients with weaker memory are more likely to confabulate and the content of these confabulations are more likely to be positive. Copyright © 2015 Elsevier Ltd. All rights reserved.

Study of false positives in 5-ALA induced photodynamic diagnosis of bladder carcinoma

NASA Astrophysics Data System (ADS)

Draga, Ronald O. P.; Grimbergen, Matthijs C. M.; Kok, Esther T.; Jonges, Trudy G. N.; Bosch, J. L. H. R.

2009-02-01

Photodynamic diagnosis (PDD) is a technique that enhances the detection of tumors during cystoscopy using a photosensitizer which accumulates primarily in cancerous cells and will fluoresce when illuminated by violetblue light. A disadvantage of PDD is the relatively low specificity. In this retrospective study we aimed to identify predictors for false positive findings in PDD. Factors such as gender, age, recent transurethral resection of bladder tumors (TURBT), previous intravesical therapy (IVT) and urinary tract infections (UTIs) were examined for association with the false positive rates in a multivariate analysis. Data of 366 procedures and 200 patients were collected. Patients were instilled with 5-aminolevulinic acid (5-ALA) intravesically and 1253 biopsies were taken from tumors and suspicious lesions. Female gender and TURBT are independent predictors of false positives in PDD. However, previous intravesical therapy with Bacille Calmette-Guérin is also an important predictor of false positives. The false positive rate decreases during the first 9-12 weeks after the latest TURBT and the latest intravesical chemotherapy. Although shortly after IVT and TURBT false positives increase, PDD improves the diagnostic sensitivity and results in more adequate treatment strategies in a significant number of patients.

Can computed tomography esophagography reliably diagnose traumatic penetrating upper digestive tract injuries?

PubMed

Conradie, Wilhelmus Jacobus; Gebremariam, Fekade Admassu

2015-01-01

To determine the sensitivity and specificity of computed tomography (CT) esophagography in diagnosing penetrating esophageal and hypopharyngeal injuries in trauma patients and to see if it can be used as the only imaging method in diagnosing these injuries. The confidence of radiologists using only CT esophagography was also measured. A prospective cross-sectional analytic study was done on haemodinamically stable patients requiring multidetector CT after external penetrating neck or chest trauma. Each patient was given oral contrast consisting of 50 ml 50% iohexol solution, within 5 min of commencement of the CT examination and in the supine position. An attempt was made to confirm all CT esophagography findings with at least one secondary method. Images were evaluated separately by two general departmental radiologists who were blinded to the results of the confirmation method. Between December 2012 and November 2014, 102 patients were included, of which 93 (91.2%) were male. Stab wounds were responsible for 85.3% (n=87) of penetrating wounds. Ninety-four patients (92.2%) had CT angiography (CTA) in conjunction with CT esophagography. There were 20 confirmed upper digestive tract injuries; 11 (55.0%) in the hypopharynx and 9 (45.0%) in the esophagus. With the exception of one case, all upper digestive tract injuries were diagnosed using only CT esophagography. No upper digestive tract injuries were correctly identified in 70 and 75 out of 82 true negative cases respectively, suggesting a sensitivity of 95.0% for both radiologists and specificity of 85.4% and 91.5% for CT esophagography. A number of false positive diagnoses were reported when CT esophagography was done in conjunction with CTA, resulting in a positive predictive value of 61.3% and 79.1% for this technique. Reviewers were positive to very confident about the CT esophagography findings in 90.0% and 100% of patients with injuries and 79.0% and 87.0%, respectively, in the no injury group. CT esophagography is reliable in diagnosing penetrating upper digestive tract injuries. In conjunction with CTA, false positive findings may occur. Radiologists were generally positive to very confident about their CT esophagography findings, not needing further imaging in more than 60% of cases. Copyright © 2015 Elsevier Inc. All rights reserved.

Diagnosing the occult contralateral inguinal hernia.

PubMed

Koehler, R H

2002-03-01

The incidence of bilateral inguinal hernias reported for total extra peritoneal (TEP) laparoscopic hernia repair, which reaches 45%, appears to be higher than that seen in studies of transabdominal laparoscopic and open repair. Given the unique ability of diagnostic laparoscopy to diagnose occult contralateral hernias (OCH) accurately, this study looked at how concurrent transabdominal diagnostic laparoscopy (TADL) would influence planned TEP repairs. A prospective study oF 100 consecutive TEP cases was conducted. All patients had diagnostic laparoscopy via a 5-mm 45 degrees scope through an umbilical incision with 15 mmHg of pneumoperitoneum, followed by laparoscopic TEPrepair. A contralateral occult hernia was diagnosed and repaired if a true peritoneal eventration through the inguinal region was observed. Among the 100 patients, preoperative diagnosis suggested 31 bilateral hernias (31%), whereas TADL confirmed 25 bilateral hernias (25%). Of these 25 bilateral hernias, TADL confirmed 16 that had been diagnosed preoperatively (64%), but excluded 15 contralateral hernias that were incorrectly diagnosed (37%). Transabdominal diagnostic laparoscopy found nine OCHs, representing 36% of all bilateral hernias and 13% of the 69 preoperatively determined unilateral hernias. The preoperative physician examination false-negative rate for contralateral hernias was 36%, and the false-positive rate was 37%. In 26 cases (26%), TADL changed the operative approach. In this study, patients believed to have unilateral inguinal hernias had OCHs in 13% of cases when examined by TADL. The actual bilateral hernia incidence was 25%, with a 37% false-positive rate for preoperatively diagnosed bilateral hernias. The high rate of bilateral hernias reported by the TEP approach alone suggests that some OCH findings may be an artifact of the TEP dissection. However, failure to search for an OCH could result in up to 13% of patients subsequently requiring a second repair. Because some surgeons are concerned about unnecessary TEP dissection of the asymptomatic contralateral side, the approach described here may offer a solution to accurate diagnosis of the contralateral inguinal region during planned laparoscopic TEP hernia repair.

[Automated detection of estrus and mastitis in dairy cows].

PubMed

de Mol, R M

2001-02-15

The development and test of detection models for oestrus and mastitis in dairy cows is described in a PhD thesis that was defended in Wageningen on June 5, 2000. These models were based on sensors for milk yield, milk temperature, electrical conductivity of milk, and cow activity and concentrate intake, and on combined processing of the sensor data. The models alert farmers to cows that need attention, because of possible oestrus or mastitis. A first detection model for cows, milked twice a day, was based on time series models for the sensor variables. A time series model describes the dependence between successive observations. The parameters of the time series models were fitted on-line for each cow after each milking by means of a Kalman filter, a mathematical method to estimate the state of a system on-line. The Kalman filter gives the best estimate of the current state of a system based on all preceding observations. This model was tested for 2 years on two experimental farms, and under field conditions on four farms over several years. A second detection model, for cow milked in an automatic milking system (AMS), was based on a generalization of the first model. Two data sets (one small, one large) were used for testing. The results for oestrus detection were good for both models. The results for mastitis detection were varying (in some cases good, in other cases moderate). Fuzzy logic was used to classify mastitis and oestrus alerts with both detection models, to reduce the number of false positive alerts. Fuzzy logic makes approximate reasoning possible, where statements can be partly true or false. Input for the fuzzy logic model were alerts from the detection models and additional information. The number of false positive alerts decreased considerably, while the number of detected cases remained at the same level. These models make automated detection possible in practice.

The health system impact of false positive newborn screening results for medium-chain acyl-CoA dehydrogenase deficiency: a cohort study.

PubMed

Karaceper, Maria D; Chakraborty, Pranesh; Coyle, Doug; Wilson, Kumanan; Kronick, Jonathan B; Hawken, Steven; Davies, Christine; Brownell, Marni; Dodds, Linda; Feigenbaum, Annette; Fell, Deshayne B; Grosse, Scott D; Guttmann, Astrid; Laberge, Anne-Marie; Mhanni, Aizeddin; Miller, Fiona A; Mitchell, John J; Nakhla, Meranda; Prasad, Chitra; Rockman-Greenberg, Cheryl; Sparkes, Rebecca; Wilson, Brenda J; Potter, Beth K

2016-02-03

There is no consensus in the literature regarding the impact of false positive newborn screening results on early health care utilization patterns. We evaluated the impact of false positive newborn screening results for medium-chain acyl-CoA dehydrogenase deficiency (MCADD) in a cohort of Ontario infants. The cohort included all children who received newborn screening in Ontario between April 1, 2006 and March 31, 2010. Newborn screening and diagnostic confirmation results were linked to province-wide health care administrative datasets covering physician visits, emergency department visits, and inpatient hospitalizations, to determine health service utilization from April 1, 2006 through March 31, 2012. Incidence rate ratios (IRRs) were used to compare those with false positive results for MCADD to those with negative newborn screening results, stratified by age at service use. We identified 43 infants with a false positive newborn screening result for MCADD during the study period. These infants experienced significantly higher rates of physician visits (IRR: 1.42) and hospitalizations (IRR: 2.32) in the first year of life relative to a screen negative cohort in adjusted analyses. Differences in health services use were not observed after the first year of life. The higher use of some health services among false positive infants during the first year of life may be explained by a psychosocial impact of false positive results on parental perceptions of infant health, and/or by differences in underlying health status. Understanding the impact of false positive newborn screening results can help to inform newborn screening programs in designing support and education for families. This is particularly important as additional disorders are added to expanded screening panels, yielding important clinical benefits for affected children but also a higher frequency of false positive findings.

Accounting for false-positive acoustic detections of bats using occupancy models

USGS Publications Warehouse

Clement, Matthew J.; Rodhouse, Thomas J.; Ormsbee, Patricia C.; Szewczak, Joseph M.; Nichols, James D.

2014-01-01

4. Synthesis and applications. Our results suggest that false positives sufficient to affect inferences may be common in acoustic surveys for bats. We demonstrate an approach that can estimate occupancy, regardless of the false-positive rate, when acoustic surveys are paired with capture surveys. Applications of this approach include monitoring the spread of White-Nose Syndrome, estimating the impact of climate change and informing conservation listing decisions. We calculate a site-specific probability of occupancy, conditional on survey results, which could inform local permitting decisions, such as for wind energy projects. More generally, the magnitude of false positives suggests that false-positive occupancy models can improve accuracy in research and monitoring of bats and provide wildlife managers with more reliable information.

Validation of a Syndromic Case Definition for Detecting Emergency Department Visits Potentially Related to Marijuana.

PubMed

DeYoung, Kathryn; Chen, Yushiuan; Beum, Robert; Askenazi, Michele; Zimmerman, Cali; Davidson, Arthur J

Reliable methods are needed to monitor the public health impact of changing laws and perceptions about marijuana. Structured and free-text emergency department (ED) visit data offer an opportunity to monitor the impact of these changes in near-real time. Our objectives were to (1) generate and validate a syndromic case definition for ED visits potentially related to marijuana and (2) describe a method for doing so that was less resource intensive than traditional methods. We developed a syndromic case definition for ED visits potentially related to marijuana, applied it to BioSense 2.0 data from 15 hospitals in the Denver, Colorado, metropolitan area for the period September through October 2015, and manually reviewed each case to determine true positives and false positives. We used the number of visits identified by and the positive predictive value (PPV) for each search term and field to refine the definition for the second round of validation on data from February through March 2016. Of 126 646 ED visits during the first period, terms in 524 ED visit records matched ≥1 search term in the initial case definition (PPV, 92.7%). Of 140 932 ED visits during the second period, terms in 698 ED visit records matched ≥1 search term in the revised case definition (PPV, 95.7%). After another revision, the final case definition contained 6 keywords for marijuana or derivatives and 5 diagnosis codes for cannabis use, abuse, dependence, poisoning, and lung disease. Our syndromic case definition and validation method for ED visits potentially related to marijuana could be used by other public health jurisdictions to monitor local trends and for other emerging concerns.

Uncertainty in biological monitoring: a framework for data collection and analysis to account for multiple sources of sampling bias

USGS Publications Warehouse

Ruiz-Gutierrez, Viviana; Hooten, Melvin B.; Campbell Grant, Evan H.

2016-01-01

Biological monitoring programmes are increasingly relying upon large volumes of citizen-science data to improve the scope and spatial coverage of information, challenging the scientific community to develop design and model-based approaches to improve inference.Recent statistical models in ecology have been developed to accommodate false-negative errors, although current work points to false-positive errors as equally important sources of bias. This is of particular concern for the success of any monitoring programme given that rates as small as 3% could lead to the overestimation of the occurrence of rare events by as much as 50%, and even small false-positive rates can severely bias estimates of occurrence dynamics.We present an integrated, computationally efficient Bayesian hierarchical model to correct for false-positive and false-negative errors in detection/non-detection data. Our model combines independent, auxiliary data sources with field observations to improve the estimation of false-positive rates, when a subset of field observations cannot be validated a posteriori or assumed as perfect. We evaluated the performance of the model across a range of occurrence rates, false-positive and false-negative errors, and quantity of auxiliary data.The model performed well under all simulated scenarios, and we were able to identify critical auxiliary data characteristics which resulted in improved inference. We applied our false-positive model to a large-scale, citizen-science monitoring programme for anurans in the north-eastern United States, using auxiliary data from an experiment designed to estimate false-positive error rates. Not correcting for false-positive rates resulted in biased estimates of occupancy in 4 of the 10 anuran species we analysed, leading to an overestimation of the average number of occupied survey routes by as much as 70%.The framework we present for data collection and analysis is able to efficiently provide reliable inference for occurrence patterns using data from a citizen-science monitoring programme. However, our approach is applicable to data generated by any type of research and monitoring programme, independent of skill level or scale, when effort is placed on obtaining auxiliary information on false-positive rates.

Fired Cartridge Case Identification Using Optical Images and the Congruent Matching Cells (CMC) Method

PubMed Central

Tong, Mingsi; Song, John; Chu, Wei; Thompson, Robert M

2014-01-01

The Congruent Matching Cells (CMC) method for ballistics identification was invented at the National Institute of Standards and Technology (NIST). The CMC method is based on the correlation of pairs of small correlation cells instead of the correlation of entire images. Four identification parameters – TCCF, Tθ, Tx and Ty are proposed for identifying correlated cell pairs originating from the same firearm. The correlation conclusion (matching or non-matching) is determined by whether the number of CMC is ≥ 6. This method has been previously validated using a set of 780 pair-wise 3D topography images. However, most ballistic images stored in current local and national databases are in an optical intensity (grayscale) format. As a result, the reliability of applying the CMC method on optical intensity images is an important issue. In this paper, optical intensity images of breech face impressions captured on the same set of 40 cartridge cases are correlated and analyzed for the validation test of CMC method using optical images. This includes correlations of 63 pairs of matching images and 717 pairs of non-matching images under top ring lighting. Tests of the method do not produce any false identification (false positive) or false exclusion (false negative) results, which support the CMC method and the proposed identification criterion, C = 6, for firearm breech face identifications using optical intensity images. PMID:26601045

Fired Cartridge Case Identification Using Optical Images and the Congruent Matching Cells (CMC) Method.

PubMed

Tong, Mingsi; Song, John; Chu, Wei; Thompson, Robert M

2014-01-01

The Congruent Matching Cells (CMC) method for ballistics identification was invented at the National Institute of Standards and Technology (NIST). The CMC method is based on the correlation of pairs of small correlation cells instead of the correlation of entire images. Four identification parameters - T CCF, T θ, T x and T y are proposed for identifying correlated cell pairs originating from the same firearm. The correlation conclusion (matching or non-matching) is determined by whether the number of CMC is ≥ 6. This method has been previously validated using a set of 780 pair-wise 3D topography images. However, most ballistic images stored in current local and national databases are in an optical intensity (grayscale) format. As a result, the reliability of applying the CMC method on optical intensity images is an important issue. In this paper, optical intensity images of breech face impressions captured on the same set of 40 cartridge cases are correlated and analyzed for the validation test of CMC method using optical images. This includes correlations of 63 pairs of matching images and 717 pairs of non-matching images under top ring lighting. Tests of the method do not produce any false identification (false positive) or false exclusion (false negative) results, which support the CMC method and the proposed identification criterion, C = 6, for firearm breech face identifications using optical intensity images.

[Predictive factors of contamination in a blood culture with bacterial growth in an Emergency Department].

PubMed

Hernández-Bou, S; Trenchs Sainz de la Maza, V; Esquivel Ojeda, J N; Gené Giralt, A; Luaces Cubells, C

2015-06-01

The aim of this study is to identify predictive factors of bacterial contamination in positive blood cultures (BC) collected in an emergency department. A prospective, observational and analytical study was conducted on febrile children aged on to 36 months, who had no risk factors of bacterial infection, and had a BC collected in the Emergency Department between November 2011 and October 2013 in which bacterial growth was detected. The potential BC contamination predicting factors analysed were: maximum temperature, time to positivity, initial Gram stain result, white blood cell count, absolute neutrophil count, band count, and C-reactive protein (CRP). Bacteria grew in 169 BC. Thirty (17.8%) were finally considered true positives and 139 (82.2%) false positives. All potential BC contamination predicting factors analysed, except maximum temperature, showed significant differences between true positives and false positives. CRP value, time to positivity, and initial Gram stain result are the best predictors of false positives in BC. The positive predictive values of a CRP value≤30mg/L, BC time to positivity≥16h, and initial Gram stain suggestive of a contaminant in predicting a FP, are 95.1, 96.9 and 97.5%, respectively. When all 3 conditions are applied, their positive predictive value is 100%. Four (8.3%) patients with a false positive BC and discharged to home were revaluated in the Emergency Department. The majority of BC obtained in the Emergency Department that showed positive were finally considered false positives. Initial Gram stain, time to positivity, and CRP results are valuable diagnostic tests in distinguishing between true positives and false positives in BC. The early detection of false positives will allow minimising their negative consequences. Copyright © 2014 Asociación Española de Pediatría. Published by Elsevier España, S.L.U. All rights reserved.

Interpreting the results of the Semmes-Weinstein monofilament test: accounting for false-positive answers in the international consensus on the diabetic foot protocol by a new model.

PubMed

Slater, Robert A; Koren, Shlomit; Ramot, Yoram; Buchs, Andreas; Rapoport, Micha J

2014-01-01

The Semmes-Weinstein monofilament is the most widely used test to diagnose the loss of protective sensation. The commonly used protocol of the International Consensus on the Diabetic Foot includes a 'sham' application that allows for false-positive answers. We sought to study the heretofore unexamined significance of false-positive answers. Forty-five patients with diabetes and a history of pedal ulceration (Group I) and 81 patients with diabetes but no history of ulceration (Group II) were studied. The three original sites of the International Consensus on the Diabetic Foot at the hallux, 1st metatarsal and 5th metatarsal areas were used. At each location, the test was performed three times: 2 actual and 1 "sham" applications. Scores were graded from 0 to 3 based upon correct responses. Determination of loss of protective sensation was performed with and without calculating a false-positive answer as a minus 1 score. False-positive responses were found in a significant percentage of patients with and without history of ulceration. Introducing false-positive results as minus 1 into the test outcome significantly increased the number of patients diagnosed with loss of protective sensation in both groups. False-positive answers can significantly affect Semmes-Weinstein monofilament test results and the diagnosis of LOPS. A model that accounts for false-positive answers is offered. Copyright © 2013 John Wiley & Sons, Ltd.

INFRARED- BASED BLINK DETECTING GLASSES FOR FACIAL PACING: TOWARDS A BIONIC BLINK

PubMed Central

Frigerio, Alice; Hadlock, Tessa A; Murray, Elizabeth H; Heaton, James T

2015-01-01

IMPORTANCE Facial paralysis remains one of the most challenging conditions to effectively manage, often causing life-altering deficits in both function and appearance. Facial rehabilitation via pacing and robotic technology has great yet unmet potential. A critical first step towards reanimating symmetrical facial movement in cases of unilateral paralysis is the detection of healthy movement to use as a trigger for stimulated movement. OBJECTIVE To test a blink detection system that can be attached to standard eyeglasses and used as part of a closed-loop facial pacing system. DESIGN Standard safety glasses were equipped with an infrared (IR) emitter/detector pair oriented horizontally across the palpebral fissure, creating a monitored IR beam that became interrupted when the eyelids closed. SETTING Tertiary care Facial Nerve Center. PARTICIPANTS 24 healthy volunteers. MAIN OUTCOME MEASURE Video-quantified blinking was compared with both IR sensor signal magnitude and rate of change in healthy participants with their gaze in repose, while they shifted gaze from central to far peripheral positions, and during the production of particular facial expressions. RESULTS Blink detection based on signal magnitude achieved 100% sensitivity in forward gaze, but generated false-detections on downward gaze. Calculations of peak rate of signal change (first derivative) typically distinguished blinks from gaze-related lid movements. During forward gaze, 87% of detected blink events were true positives, 11% were false positives, and 2% false negatives. Of the 11% false positives, 6% were associated with partial eyelid closures. During gaze changes, false blink detection occurred 6.3% of the time during lateral eye movements, 10.4% during upward movements, 46.5% during downward movements, and 5.6% for movements from an upward or downward gaze back to the primary gaze. Facial expressions disrupted sensor output if they caused substantial squinting or shifted the glasses. CONCLUSION AND RELEVANCE Our blink detection system provides a reliable, non-invasive indication of eyelid closure using an invisible light beam passing in front of the eye. Future versions will aim to mitigate detection errors by using multiple IR emitter/detector pairs mounted on the glasses, and alternative frame designs may reduce shifting of the sensors relative to the eye during facial movements. PMID:24699708

Journal of Special Operations Medicine. Volume 7, Edition 4, Fall 2007

DTIC Science & Technology

2007-01-01

which demonstrated massive amounts of pericardial fat , but no blood (a false positive FAST). Exploratory laparatomy revealed a catastrophic supra...ARTERIAL GAS EMBOLISM An additional concern in the unconscious diver is barotrauma and arterial gas embolism (AGE). Boyle’s law states that as pressure...ment in 32 cases of air embolism (abs). Proceedings: Joint Meeting on Diving andHyperbaric Medicine, 11-18 August. Amsterdam, The Netherlands, pg. 90. 13

ALK status testing in non-small cell lung carcinoma: correlation between ultrasensitive IHC and FISH.

PubMed

Minca, Eugen C; Portier, Bryce P; Wang, Zhen; Lanigan, Christopher; Farver, Carol F; Feng, Yan; Ma, Patrick C; Arrossi, Valeria A; Pennell, Nathan A; Tubbs, Raymond R

2013-05-01

ALK gene rearrangements in advanced non-small cell lung carcinomas (NSCLC) are an indication for targeted therapy with crizotinib. Fluorescence in situ hybridization (FISH) using a recently approved companion in vitro diagnostic class FISH system commonly assesses ALK status. More accessible IHC is challenged by low expression of ALK-fusion transcripts in NSCLC. We compared ultrasensitive automated IHC with FISH for detecting ALK status on 318 FFPE and 40 matched ThinPrep specimens from 296 patients with advanced NSCLC. IHC was concordant with FFPE-FISH on 229 of 231 dual-informative samples (31 positive and 198 negative) and with ThinPrep-FISH on 34 of 34 samples (5 positive and 29 negative). Two cases with negative IHC and borderline-positive FFPE-FISH (15% and 18%, respectively) were reclassified as concordant based on negative matched ThinPrep-FISH and clinical data consistent with ALK-negative status. Overall, after including ThinPrep-FISH and amending the false-positive FFPE-FISH results, IHC demonstrated 100% sensitivity and specificity (95% CI, 0.86 to 1.00 and 0.97 to 1.00, respectively) for ALK detection on 249 dual-informative NSCLC samples. IHC was informative on significantly more samples than FFPE-FISH, revealing additional ALK-positive cases. The high concordance with FISH warrants IHC's routine use as the initial component of an algorithmic approach to clinical ALK testing in NSCLC, followed by reflex FISH confirmation of IHC-positive cases. Copyright © 2013 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

Reducing false-positive incidental findings with ensemble genotyping and logistic regression based variant filtering methods.

PubMed

Hwang, Kyu-Baek; Lee, In-Hee; Park, Jin-Ho; Hambuch, Tina; Choe, Yongjoon; Kim, MinHyeok; Lee, Kyungjoon; Song, Taemin; Neu, Matthew B; Gupta, Neha; Kohane, Isaac S; Green, Robert C; Kong, Sek Won

2014-08-01

As whole genome sequencing (WGS) uncovers variants associated with rare and common diseases, an immediate challenge is to minimize false-positive findings due to sequencing and variant calling errors. False positives can be reduced by combining results from orthogonal sequencing methods, but costly. Here, we present variant filtering approaches using logistic regression (LR) and ensemble genotyping to minimize false positives without sacrificing sensitivity. We evaluated the methods using paired WGS datasets of an extended family prepared using two sequencing platforms and a validated set of variants in NA12878. Using LR or ensemble genotyping based filtering, false-negative rates were significantly reduced by 1.1- to 17.8-fold at the same levels of false discovery rates (5.4% for heterozygous and 4.5% for homozygous single nucleotide variants (SNVs); 30.0% for heterozygous and 18.7% for homozygous insertions; 25.2% for heterozygous and 16.6% for homozygous deletions) compared to the filtering based on genotype quality scores. Moreover, ensemble genotyping excluded > 98% (105,080 of 107,167) of false positives while retaining > 95% (897 of 937) of true positives in de novo mutation (DNM) discovery in NA12878, and performed better than a consensus method using two sequencing platforms. Our proposed methods were effective in prioritizing phenotype-associated variants, and an ensemble genotyping would be essential to minimize false-positive DNM candidates. © 2014 WILEY PERIODICALS, INC.

Reducing false positive incidental findings with ensemble genotyping and logistic regression-based variant filtering methods

PubMed Central

Hwang, Kyu-Baek; Lee, In-Hee; Park, Jin-Ho; Hambuch, Tina; Choi, Yongjoon; Kim, MinHyeok; Lee, Kyungjoon; Song, Taemin; Neu, Matthew B.; Gupta, Neha; Kohane, Isaac S.; Green, Robert C.; Kong, Sek Won

2014-01-01

As whole genome sequencing (WGS) uncovers variants associated with rare and common diseases, an immediate challenge is to minimize false positive findings due to sequencing and variant calling errors. False positives can be reduced by combining results from orthogonal sequencing methods, but costly. Here we present variant filtering approaches using logistic regression (LR) and ensemble genotyping to minimize false positives without sacrificing sensitivity. We evaluated the methods using paired WGS datasets of an extended family prepared using two sequencing platforms and a validated set of variants in NA12878. Using LR or ensemble genotyping based filtering, false negative rates were significantly reduced by 1.1- to 17.8-fold at the same levels of false discovery rates (5.4% for heterozygous and 4.5% for homozygous SNVs; 30.0% for heterozygous and 18.7% for homozygous insertions; 25.2% for heterozygous and 16.6% for homozygous deletions) compared to the filtering based on genotype quality scores. Moreover, ensemble genotyping excluded > 98% (105,080 of 107,167) of false positives while retaining > 95% (897 of 937) of true positives in de novo mutation (DNM) discovery, and performed better than a consensus method using two sequencing platforms. Our proposed methods were effective in prioritizing phenotype-associated variants, and ensemble genotyping would be essential to minimize false positive DNM candidates. PMID:24829188

Assessing HTS Performance Using BioAssay Ontology: Screening and Analysis of a Bacterial Phospho-N-Acetylmuramoyl-Pentapeptide Translocase Campaign

PubMed Central

Moberg, Andreas; Hansson, Eva; Boyd, Helen

2014-01-01

Abstract With the public availability of biochemical assays and screening data constantly increasing, new applications for data mining and method analysis are evolving in parallel. One example is BioAssay Ontology (BAO) for systematic classification of assays based on screening setup and metadata annotations. In this article we report a high-throughput screening (HTS) against phospho-N-acetylmuramoyl-pentapeptide translocase (MraY), an attractive antibacterial drug target involved in peptidoglycan synthesis. The screen resulted in novel chemistry identification using a fluorescence resonance energy transfer assay. To address a subset of the false positive hits, a frequent hitter analysis was performed using an approach in which MraY hits were compared with hits from similar assays, previously used for HTS. The MraY assay was annotated according to BAO and three internal reference assays, using a similar assay design and detection technology, were identified. Analyzing the assays retrospectively, it was clear that both MraY and the three reference assays all showed a high false positive rate in the primary HTS assays. In the case of MraY, false positives were efficiently identified by applying a method to correct for compound interference at the hit-confirmation stage. Frequent hitter analysis based on the three reference assays with similar assay method identified additional false actives in the primary MraY assay as frequent hitters. This article demonstrates how assays annotated using BAO terms can be used to identify closely related reference assays, and that analysis based on these assays clearly can provide useful data to influence assay design, technology, and screening strategy. PMID:25415593

Clinical value of polymerase chain reaction in the diagnosis of joint tuberculosis by detecting the DNA of Mycobacterium tuberculosis.

PubMed

Sun, Yong-sheng; Lou, Si-quan; Wen, Jian-min; Lv, Wei-xin; Jiao, Chang-geng; Yang, Su-min; Xu, Hai-bin

2011-02-01

To assess the clinical value of polymerase chain reaction (PCR) in the diagnosis and differential diagnosis of joint tuberculosis (TB). PCR was used blindly to detect the DNA of Mycobacterium tuberculosis (M.TB) in five specimens of M.TB, 5 of BCG, and 10 of other bacteria. Then, M. TB in 98 samples from patients with joint TB and 100 samples from patients with non-tubercular joint disorders were detected by PCR, acid-fast staining and culture,. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of PCR were calculated. The χ2 test was used for statistical analysis of the frequency of various factors. At the same time, some problems with PCR were also systematically analyzed. (1) In the "standard samples", both M. TB and BCG showed positive while other bacteria were negative. (2) In 98 cases from patients with joint TB, 81 were positive by PCR, 6 by acid-fast staining, and 17 by culture. In 100 cases from patients with non-tuberculous joint disorders, 9 were positive by PCR, and none by either acid-fast staining or culture. Sensitivity, specificity, accuracy, positive and negative predictive value of PCR were 82.65% (81/98), 91.00% (91/100), 86.87% (172/198), 90.00% (81/90) and 84.26% (91/108), respectively. (3) The positive rates for PCR, acid-fast staining and culture in detection of M. TB were 82.65% (81/98), 6.12% (6/98), and 17.34% (17/98), respectively. There were statistically significant differences between the three methods (P < 0.001). (4) The process of PCR is automatic, and can be completed within 3 to 6 hours, whereas 4 to 8 weeks are required for the conventional culture of M. TB. PCR is a sensitive, specific, rapid, simple and minimally invasive method for detection of M. TB in samples from joint TB, and can play an important role in early and rapid diagnosis and differential diagnosis of joint TB. But it also has some limitations, such as false positivity and false negativity. © 2011 Tianjin Hospital and Blackwell Publishing Asia Pty Ltd.

A false positive newborn screening result due to a complex allele carrying two frequent CF-causing variants.

PubMed

Bergougnoux, Anne; Boureau-Wirth, Amandine; Rouzier, Cécile; Altieri, Jean-Pierre; Verneau, Fanny; Larrieu, Lise; Koenig, Michel; Claustres, Mireille; Raynal, Caroline

2016-05-01

The detection of two frequent CFTR disease-causing variations in the context of a newborn screening program (NBS) usually leads to the diagnosis of cystic fibrosis (CF) and a relevant genetic counseling in the family. In the present study, CF-causing variants p.Phe508del (F508del) and c.3140-26A>G (3272-26A>G) were identified on a neonate with positive ImmunoReactive Trypsinogen test by the Elucigene™ CF30 kit. The CF diagnosis initially suggested, despite three inconclusive Sweat Chloride Tests (SCT), was finally ruled out after the familial segregation study combined with a negative SCT. Haplotype studies, based on the comparison of 80 p.Phe508del haplotypes, suggested a probable de novo occurrence of c.3140-26A>G on the p.Phe508del ancestral allele in this family. This false positive case emphasizes the importance of SCT in the NBS strategy. Moreover, it raises the need for familial segregation studies in CF and in overall molecular diagnosis strategy of autosomal recessive diseases. Copyright © 2016 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

A prospective study: Is handheld micropower impulse radar technology (Pneumoscan) a promising method to detect pneumothorax?

PubMed

Hocagil, Hilal; Hocagil, Abdullah Cüneyt; Karacabey, Sinan; Akkaya, Tuğba; Şimşek, Gözde; Sanrı, Erkman

2015-09-01

This study aimed to discuss the effectiveness of Pneumoscan working with micropower impulse radar (MIR) technology in diagnosing pneumothorax (PTX) in the emergency department. Patients with suspicion of PTX and indication for thorax tomography (CT) were included into the study. Findings of the Thorax CT were compared with the results of Pneumoscan. Chi-square and Fisher's exact tests were used in categorical variables. One hundred and fifteen patients were included into the study group; twelve patients presented with PTX diagnosed by CT, 10 of which were detected by Pneumoscan. Thirty-six true negative results, sixty-seven false positive results, and two false negative results were obtained, which resulted in an overall sensitivity of 83.3%, specificity of 35.0% for Pneumoscan. There was no statistically significant difference between the effectiveness of Pneumoscan and CT on the detection of PTX (p=0.33). There was no difference between the size of PTX diagnosed by CT and PTX diagnosed by Pneumoscan (p=0.47). There was no statistically significant difference between Pneumoscan and CT on detecting the localisation of the PTX (p=1.00). For the 10 cases diagnosed by Pneumoscan, mean chest wall thickness was determined as 50.3 mm while mean chest wall thickness for two false negatives diagnosed by Pneumoscan was 56.5 mm. However, no statistically significant difference was found between the chest wall thickness and the effectiveness of Pneumoscan on the detection of the PTX (p=0.77). Among sixty-seven false positives diagnosed by Pneumoscan, 46.3% had additional medical signs such as bronchiectasis, pulmonary consolidation, pulmonary edema or pulmonary tumor when they had a reading with CT. The relationship between having additional medical signs at the reading with CT and the effectiveness of Pneumoscan on the detection of the PTX was investigated and no significant difference was found (p=0.472). Using Pneumoscan to detect PTX is controversial since the device has a high false positive ratio. Wherein, false positive diagnosis can cause unjustifiable chest tube insertion. In addition, the device failed to show the size of the PTX, and therefore, it did not aid in determining the treatment and prognosis on contrary to traditional diagnostic methods. The findings could not demonstrate that the device was efficient in emergency care. Further studies and increasing experience may change this outcome in upcoming years.

Detection of feline herpes virus 1 via polymerase chain reaction and immunohistochemistry in cats with ulcerative facial dermatitis, eosinophilic granuloma complex reaction patterns and mosquito bite hypersensitivity.

PubMed

Persico, Paola; Roccabianca, Paola; Corona, Antonio; Vercelli, Antonella; Cornegliani, Luisa

2011-12-01

Ulcerative dermatitis caused by feline herpes virus 1 (FHV-1) is an uncommon disease characterized by cutaneous ulcers secondary to epidermal, adnexal and dermal necrosis. Differential diagnoses for FHV-1 lesions include, but are not limited to, mosquito bite hypersensitivity and eosinophilic granuloma complex. Histopathological diagnosis of FHV-1 dermatitis is based on the detection of the intranuclear inclusion bodies. In cases where intranuclear inclusions are missing but clinical and histological findings are compatible with FHV-1 dermatitis, immunohistochemistry (IHC) and PCRs have been used. In this retrospective study, we evaluated the presence of FHV-1 by IHC and PCR in skin biopsies and compared the results of the two tests. Sixty-four skin biopsy specimens from cats with compatible lesions were reviewed and tested via PCR and IHC for evidence of FHV-1. Polymerase chain reaction was positive in 12 of 64 biopsies; PCR and IHC were positive only in two of 64 biopsies, and these cases were considered true positive cases. The higher number of PCR-positive cases was possibly attributed to amplification of viral DNA from a live attenuated vaccination, but a previous FHV-1 infection with subsequent amplification of latently inserted FHV-1 could not be excluded. If clinical signs and histopathology suggest FHV-1 infection in the absence of typical inclusion bodies, IHC is the preferred diagnostic test; PCR may be useful for initial screening, but due to false positives is not sufficient for a definitive diagnosis. © 2011 The Authors. Veterinary Dermatology. © 2011 ESVD and ACVD.

Adaptive error detection for HDR/PDR brachytherapy: Guidance for decision making during real-time in vivo point dosimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kertzscher, Gustavo, E-mail: guke@dtu.dk; Andersen, Claus E., E-mail: clan@dtu.dk; Tanderup, Kari, E-mail: karitand@rm.dk

Purpose: This study presents an adaptive error detection algorithm (AEDA) for real-timein vivo point dosimetry during high dose rate (HDR) or pulsed dose rate (PDR) brachytherapy (BT) where the error identification, in contrast to existing approaches, does not depend on an a priori reconstruction of the dosimeter position. Instead, the treatment is judged based on dose rate comparisons between measurements and calculations of the most viable dosimeter position provided by the AEDA in a data driven approach. As a result, the AEDA compensates for false error cases related to systematic effects of the dosimeter position reconstruction. Given its nearly exclusivemore » dependence on stable dosimeter positioning, the AEDA allows for a substantially simplified and time efficient real-time in vivo BT dosimetry implementation. Methods: In the event of a measured potential treatment error, the AEDA proposes the most viable dosimeter position out of alternatives to the original reconstruction by means of a data driven matching procedure between dose rate distributions. If measured dose rates do not differ significantly from the most viable alternative, the initial error indication may be attributed to a mispositioned or misreconstructed dosimeter (false error). However, if the error declaration persists, no viable dosimeter position can be found to explain the error, hence the discrepancy is more likely to originate from a misplaced or misreconstructed source applicator or from erroneously connected source guide tubes (true error). Results: The AEDA applied on twoin vivo dosimetry implementations for pulsed dose rate BT demonstrated that the AEDA correctly described effects responsible for initial error indications. The AEDA was able to correctly identify the major part of all permutations of simulated guide tube swap errors and simulated shifts of individual needles from the original reconstruction. Unidentified errors corresponded to scenarios where the dosimeter position was sufficiently symmetric with respect to error and no-error source position constellations. The AEDA was able to correctly identify all false errors represented by mispositioned dosimeters contrary to an error detection algorithm relying on the original reconstruction. Conclusions: The study demonstrates that the AEDA error identification during HDR/PDR BT relies on a stable dosimeter position rather than on an accurate dosimeter reconstruction, and the AEDA’s capacity to distinguish between true and false error scenarios. The study further shows that the AEDA can offer guidance in decision making in the event of potential errors detected with real-timein vivo point dosimetry.« less

The problem of false positives and false negatives in violent video game experiments.

PubMed

Ferguson, Christopher J

The problem of false positives and negatives has received considerable attention in behavioral research in recent years. The current paper uses video game violence research as an example of how such issues may develop in a field. Despite decades of research, evidence on whether violent video games (VVGs) contribute to aggression in players has remained mixed. Concerns have been raised in recent years that experiments regarding VVGs may suffer from both "false positives" and "false negatives." The current paper examines this issue in three sets of video game experiments, two sets of video game experiments on aggression and prosocial behaviors identified in meta-analysis, and a third group of recent null studies. Results indicated that studies of VVGs and aggression appear to be particularly prone to false positive results. Studies of VVGs and prosocial behavior, by contrast are heterogeneous and did not demonstrate any indication of false positive results. However, their heterogeneous nature made it difficult to base solid conclusions on them. By contrast, evidence for false negatives in null studies was limited, and little evidence emerged that null studies lacked power in comparison those highlighted in past meta-analyses as evidence for effects. These results are considered in light of issues related to false positives and negatives in behavioral science more broadly. Copyright © 2017 Elsevier Ltd. All rights reserved.

Accounting for False Positive HIV Tests: Is Visceral Leishmaniasis Responsible?

PubMed Central

Shanks, Leslie; Ritmeijer, Koert; Piriou, Erwan; Siddiqui, M. Ruby; Kliescikova, Jarmila; Pearce, Neil; Ariti, Cono; Muluneh, Libsework; Masiga, Johnson; Abebe, Almaz

2015-01-01

Background Co-infection with HIV and visceral leishmaniasis is an important consideration in treatment of either disease in endemic areas. Diagnosis of HIV in resource-limited settings relies on rapid diagnostic tests used together in an algorithm. A limitation of the HIV diagnostic algorithm is that it is vulnerable to falsely positive reactions due to cross reactivity. It has been postulated that visceral leishmaniasis (VL) infection can increase this risk of false positive HIV results. This cross sectional study compared the risk of false positive HIV results in VL patients with non-VL individuals. Methodology/Principal Findings Participants were recruited from 2 sites in Ethiopia. The Ethiopian algorithm of a tiebreaker using 3 rapid diagnostic tests (RDTs) was used to test for HIV. The gold standard test was the Western Blot, with indeterminate results resolved by PCR testing. Every RDT screen positive individual was included for testing with the gold standard along with 10% of all negatives. The final analysis included 89 VL and 405 non-VL patients. HIV prevalence was found to be 12.8% (47/ 367) in the VL group compared to 7.9% (200/2526) in the non-VL group. The RDT algorithm in the VL group yielded 47 positives, 4 false positives, and 38 negatives. The same algorithm for those without VL had 200 positives, 14 false positives, and 191 negatives. Specificity and positive predictive value for the group with VL was less than the non-VL group; however, the difference was not found to be significant (p = 0.52 and p = 0.76, respectively). Conclusion The test algorithm yielded a high number of HIV false positive results. However, we were unable to demonstrate a significant difference between groups with and without VL disease. This suggests that the presence of endemic visceral leishmaniasis alone cannot account for the high number of false positive HIV results in our study. PMID:26161864

Accounting for False Positive HIV Tests: Is Visceral Leishmaniasis Responsible?

PubMed

Shanks, Leslie; Ritmeijer, Koert; Piriou, Erwan; Siddiqui, M Ruby; Kliescikova, Jarmila; Pearce, Neil; Ariti, Cono; Muluneh, Libsework; Masiga, Johnson; Abebe, Almaz

2015-01-01

Co-infection with HIV and visceral leishmaniasis is an important consideration in treatment of either disease in endemic areas. Diagnosis of HIV in resource-limited settings relies on rapid diagnostic tests used together in an algorithm. A limitation of the HIV diagnostic algorithm is that it is vulnerable to falsely positive reactions due to cross reactivity. It has been postulated that visceral leishmaniasis (VL) infection can increase this risk of false positive HIV results. This cross sectional study compared the risk of false positive HIV results in VL patients with non-VL individuals. Participants were recruited from 2 sites in Ethiopia. The Ethiopian algorithm of a tiebreaker using 3 rapid diagnostic tests (RDTs) was used to test for HIV. The gold standard test was the Western Blot, with indeterminate results resolved by PCR testing. Every RDT screen positive individual was included for testing with the gold standard along with 10% of all negatives. The final analysis included 89 VL and 405 non-VL patients. HIV prevalence was found to be 12.8% (47/ 367) in the VL group compared to 7.9% (200/2526) in the non-VL group. The RDT algorithm in the VL group yielded 47 positives, 4 false positives, and 38 negatives. The same algorithm for those without VL had 200 positives, 14 false positives, and 191 negatives. Specificity and positive predictive value for the group with VL was less than the non-VL group; however, the difference was not found to be significant (p = 0.52 and p = 0.76, respectively). The test algorithm yielded a high number of HIV false positive results. However, we were unable to demonstrate a significant difference between groups with and without VL disease. This suggests that the presence of endemic visceral leishmaniasis alone cannot account for the high number of false positive HIV results in our study.

Relevance of cutoff on a 4th generation ELISA performance in the false positive rate during HIV diagnostic in a low HIV prevalence setting.

PubMed

Chacón, Lucía; Mateos, María Luisa; Holguín, África

2017-07-01

Despite the high specificity of fourth-generation enzyme immunoassays (4th-gen-EIA) for screening during HIV diagnosis, their positive predictive value is low in populations with low HIV prevalence. Thus, screening should be optimized to reduce false positive results. The influence of sample cutoff (S/CO) values by a 4th-gen-EIA with the false positive rate during the routine HIV diagnosis in a low HIV prevalence population was evaluated. A total of 30,201 sera were tested for HIV diagnosis using Abbott Architect ® HIV-Ag/Ab-Combo 4th-gen-EIA at a hospital in Spain during 17 months. Architect S/CO values were recorded, comparing the HIV-1 positive results following Architect interpretation (S/CO≥1) with the final HIV-1 diagnosis by confirmatory tests (line immunoassay, LIA and/or nucleic acid test, NAT). ROC curve was also performed. Among the 30,201 HIV performed tests, 256 (0.85%) were positive according to Architect interpretation (S/CO≥1) but only 229 (0.76%) were definitively HIV-1 positive after LIA and/or NAT. Thus, 27 (10.5%) of 256 samples with S/CO≥1 by Architect were false positive diagnose. The false positive rate decreased when the S/CO ratio increased. All 19 samples with S/CO ≤10 were false positives and all 220 with S/CO>50 true HIV-positives. The optimal S/CO cutoff value provided by ROC curves was 32.7. No false negative results were found. We show that very low S/CO values during HIV-1 screening using Architect can result HIV negative after confirmation by LIA and NAT. The false positive rate is reduced when S/CO increases. Copyright © 2017 Elsevier B.V. All rights reserved.

Which Factors Contribute to False-Positive, False-Negative, and Invalid Results in Fetal Fibronectin Testing in Women with Symptoms of Preterm Labor?

PubMed

Bruijn, Merel M C; Hermans, Frederik J R; Vis, Jolande Y; Wilms, Femke F; Oudijk, Martijn A; Kwee, Anneke; Porath, Martina M; Oei, Guid; Scheepers, Hubertina C J; Spaanderman, Marc E A; Bloemenkamp, Kitty W M; Haak, Monique C; Bolte, Antoinette C; Vandenbussche, Frank P H A; Woiski, Mallory D; Bax, Caroline J; Cornette, Jérôme M J; Duvekot, Johannes J; Bijvank, Bas W A N I J; van Eyck, Jim; Franssen, Maureen T M; Sollie, Krystyna M; van der Post, Joris A M; Bossuyt, Patrick M M; Kok, Marjolein; Mol, Ben W J; van Baaren, Gert-Jan

2017-02-01

Objective  We assessed the influence of external factors on false-positive, false-negative, and invalid fibronectin results in the prediction of spontaneous delivery within 7 days. Methods  We studied symptomatic women between 24 and 34 weeks' gestational age. We performed uni- and multivariable logistic regression to estimate the effect of external factors (vaginal soap, digital examination, transvaginal sonography, sexual intercourse, vaginal bleeding) on the risk of false-positive, false-negative, and invalid results, using spontaneous delivery within 7 days as the outcome. Results  Out of 708 women, 237 (33%) had a false-positive result; none of the factors showed a significant association. Vaginal bleeding increased the proportion of positive fetal fibronectin (fFN) results, but was significantly associated with a lower risk of false-positive test results (odds ratio [OR], 0.22; 95% confidence intervals [CI], 0.12-0.39). Ten women (1%) had a false-negative result. None of the investigated factors was significantly associated with a significantly higher risk of false-negative results. Twenty-one tests (3%) were invalid; only vaginal bleeding showed a significant association (OR, 4.5; 95% CI, 1.7-12). Conclusion  The effect of external factors on the performance of qualitative fFN testing is limited, with vaginal bleeding as the only factor that reduces its validity. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Functional impairment matters in the screening and diagnosis of gaming disorder

PubMed Central

Billieux, Joël; King, Daniel L.; Higuchi, Susumu; Achab, Sophia; Bowden-Jones, Henrietta; Hao, Wei; Long, Jiang; Lee, Hae Kook; Potenza, Marc N.; Saunders, John B.; Poznyak, Vladimir

2017-01-01

This commentary responds to Aarseth et al.’s (in press) criticisms that the ICD-11 Gaming Disorder proposal would result in “moral panics around the harm of video gaming” and “the treatment of abundant false-positive cases.” The ICD-11 Gaming Disorder avoids potential “overpathologizing” with its explicit reference to functional impairment caused by gaming and therefore improves upon a number of flawed previous approaches to identifying cases with suspected gaming-related harms. We contend that moral panics are more likely to occur and be exacerbated by misinformation and lack of understanding, rather than proceed from having a clear diagnostic system. PMID:28816514

Functional impairment matters in the screening and diagnosis of gaming disorder.

PubMed

Billieux, Joël; King, Daniel L; Higuchi, Susumu; Achab, Sophia; Bowden-Jones, Henrietta; Hao, Wei; Long, Jiang; Lee, Hae Kook; Potenza, Marc N; Saunders, John B; Poznyak, Vladimir

2017-09-01

This commentary responds to Aarseth et al.'s (in press) criticisms that the ICD-11 Gaming Disorder proposal would result in "moral panics around the harm of video gaming" and "the treatment of abundant false-positive cases." The ICD-11 Gaming Disorder avoids potential "overpathologizing" with its explicit reference to functional impairment caused by gaming and therefore improves upon a number of flawed previous approaches to identifying cases with suspected gaming-related harms. We contend that moral panics are more likely to occur and be exacerbated by misinformation and lack of understanding, rather than proceed from having a clear diagnostic system.

Development of an improved CAD scheme for automated detection of lung nodules in digital chest images.

PubMed

Xu, X W; Doi, K; Kobayashi, T; MacMahon, H; Giger, M L

1997-09-01

Lung cancer is the leading cause of cancer deaths in men and women in the United States, with a 5-year survival rate of only about 13%. However, this survival rate can be improved to 47% if the disease is diagnosed and treated at an early stage. In this study, we developed an improved computer-aided diagnosis (CAD) scheme for the automated detection of lung nodules in digital chest images to assist radiologists, who could miss up to 30% of the actually positive cases in their daily practice. Two hundred PA chest radiographs, 100 normals and 100 abnormals, were used as the database for our study. The presence of nodules in the 100 abnormal cases was confirmed by two experienced radiologists on the basis of CT scans or radiographic follow-up. In our CAD scheme, nodule candidates were selected initially by multiple gray-level thresholding of the difference image (which corresponds to the subtraction of a signal-enhanced image and a signal-suppressed image) and then classified into six groups. A large number of false positives were eliminated by adaptive rule-based tests and an artificial neural network (ANN). The CAD scheme achieved, on average, a sensitivity of 70% with 1.7 false positives per chest image, a performance which was substantially better as compared with other studies. The CPU time for the processing of one chest image was about 20 seconds on an IBM RISC/6000 Powerstation 590. We believe that the CAD scheme with the current performance is ready for initial clinical evaluation.

Consensus-based identification of factors related to false-positives in ultrasound scanning of synovitis and tenosynovitis.

PubMed

Ikeda, Kei; Narita, Akihiro; Ogasawara, Michihiro; Ohno, Shigeru; Kawahito, Yutaka; Kawakami, Atsushi; Ito, Hiromu; Matsushita, Isao; Suzuki, Takeshi; Misaki, Kenta; Ogura, Takehisa; Kamishima, Tamotsu; Seto, Yohei; Nakahara, Ryuichi; Kaneko, Atsushi; Nakamura, Takayuki; Henmi, Mihoko; Fukae, Jun; Nishida, Keiichiro; Sumida, Takayuki; Koike, Takao

2016-01-01

We aimed to identify causes of false-positives in ultrasound scanning of synovial/tenosynovial/bursal inflammation and provide corresponding imaging examples. We first performed systematic literature review to identify previously reported causes of false-positives. We next determined causes of false-positives and corresponding example images for educational material through Delphi exercises and discussion by 15 experts who were an instructor and/or a lecturer in the 2013 advanced course for musculoskeletal ultrasound organized by Japan College of Rheumatology Committee for the Standardization of Musculoskeletal Ultrasonography. Systematic literature review identified 11 articles relevant to sonographic false-positives of synovial/tenosynovial inflammation. Based on these studies, 21 candidate causes of false-positives were identified in the consensus meeting. Of these items, 11 achieved a predefined consensus (≥ 80%) in Delphi exercise and were classified as follows: (I) Gray-scale assessment [(A) non-specific synovial findings and (B) normal anatomical structures which can mimic synovial lesions due to either their low echogenicity or anisotropy]; (II) Doppler assessment [(A) Intra-articular normal vessels and (B) reverberation)]. Twenty-four corresponding examples with 49 still and 23 video images also achieved consensus. Our study provides a set of representative images that can help sonographers to understand false-positives in ultrasound scanning of synovitis and tenosynovitis.

Skin irritation, false positives and the local lymph node assay: a guideline issue?

PubMed

Basketter, David A; Kimber, Ian

2011-10-01

Since the formal validation and regulatory acceptance of the local lymph node assay (LLNA) there have been commentaries suggesting that the irritant properties of substances can give rise to false positives. As toxicology aspires to progress rapidly towards the age of in vitro alternatives, it is of increasing importance that issues relating to assay selectivity and performance are understood fully, and that true false positive responses are distinguished clearly from those that are simply unpalatable. In the present review, we have focused on whether skin irritation per se is actually a direct cause of true false positive results in the LLNA. The body of published work has been examined critically and considered in relation to our current understanding of the mechanisms of skin irritation and skin sensitisation. From these analyses it is very clear that, of itself, skin irritation is not a cause of false positive results. The corollary is, therefore, that limiting test concentrations in the LLNA for the purpose of avoiding skin irritation may lead, unintentionally, to false negatives. Where a substance is a true false positive in the LLNA, the classic example being sodium lauryl sulphate, explanations for that positivity will have to reach beyond the seductive, but incorrect, recourse to its skin irritation potential. Copyright © 2011 Elsevier Inc. All rights reserved.

Hypertension is strongly associated with false-positive bicycle exercise stress echocardiography testing results.

PubMed

Keller, Karsten; Stelzer, Kathrin; Munzel, Thomas; Ostad, Mir Abolfazl

2016-12-01

Exercise echocardiography is a reliable routine test in patients with known or suspected coronary artery disease. However, in ∼15% of all patients, stress echocardiography leads to false-positive stress echocardiography results. We aimed to investigate the impact of hypertension on stress echocardiographic results. We performed a retrospective study of patients with suspected or known stable coronary artery disease who underwent a bicycle exercise stress echocardiography. Patients with false-positive stress results were compared with those with appropriate results. 126 patients with suspected or known coronary artery disease were included in this retrospective study. 23 patients showed false-positive stress echocardiography results. Beside comparable age, gender distribution and coronary artery status, hypertension was more prevalent in patients with false-positive stress results (95.7% vs. 67.0%, p = 0.0410). Exercise peak load revealed a borderline-significance with lower loads in patients with false-positive results (100.0 (IQR 75.0/137.5) vs. 125.0 (100.0/150.0) W, p = 0.0601). Patients with false-positive stress results showed higher systolic (2.05 ± 0.69 vs. 1.67 ± 0.39 mmHg/W, p = 0.0193) and diastolic (1.03 ± 0.38 vs. 0.80 ± 0.28 mmHg/W, p = 0.0165) peak blood pressure (BP) per wattage. In a multivariate logistic regression test, hypertension (OR 17.6 [CI 95% 1.9-162.2], p = 0.0115), and systolic (OR 4.12 [1.56-10.89], p = 0.00430) and diastolic (OR 13.74 [2.46-76.83], p = 0.00285) peak BP per wattage, were associated with false-positive exercise results. ROC analysis for systolic and diastolic peak BP levels per wattage showed optimal cut-off values of 1.935mmHg/W and 0.823mmHg/W, indicating false-positive exercise echocardiographic results with AUCs of 0.660 and 0.664, respectively. Hypertension is a risk factor for false-positive stress exercise echocardiographic results in patients with known or suspected coronary artery disease. Presence of hypertension was associated with 17.6-fold elevated risk of false-positive results.

Optimal Length of Cultivation Time for Isolation of Propionibacterium acnes in Suspected Bone and Joint Infections Is More than 7 Days.

PubMed

Bossard, Daniel A; Ledergerber, Bruno; Zingg, Patrick O; Gerber, Christian; Zinkernagel, Annelies S; Zbinden, Reinhard; Achermann, Yvonne

2016-12-01

Diagnosis of Propionibacterium acnes bone and joint infection is challenging due to the long cultivation time of up to 14 days. We retrospectively studied whether reducing the cultivation time to 7 days allows accurate diagnosis without losing sensitivity. We identified patients with at least one positive P. acnes sample between 2005 and 2015 and grouped them into "infection" and "no infection." An infection was defined when at least two samples from the same case were positive. Clinical and microbiological data, including time to positivity for different cultivation methods, were recorded. We found 70 cases of proven P. acnes infection with a significant faster median time to positivity of 6 days (range, 2 to 11 days) compared to 9 days in 47 cases with P. acnes identified as a contamination (P < 0.0001). In 15 of 70 (21.4%) patients with an infection, tissue samples were positive after day 7 and in 6 patients (8.6%) after day 10 when a blind subculture of the thioglycolate broth was performed. The highest sensitivity was detected for thioglycolate broth (66.3%) and the best positive predictive values for anaerobic agar plates (96.5%). A prolonged transportation time from the operating theater to the microbiological laboratory did not influence time to positivity of P. acnes growth. By reducing the cultivation time to 7 days, false-negative diagnoses would increase by 21.4%; thus, we recommend that biopsy specimens from bone and joint infections be cultivated to detect P. acnes for 10 days with a blind subculture at the end. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

False Recognition in Behavioral Variant Frontotemporal Dementia and Alzheimer's Disease-Disinhibition or Amnesia?

PubMed

Flanagan, Emma C; Wong, Stephanie; Dutt, Aparna; Tu, Sicong; Bertoux, Maxime; Irish, Muireann; Piguet, Olivier; Rao, Sulakshana; Hodges, John R; Ghosh, Amitabha; Hornberger, Michael

2016-01-01

Episodic memory recall processes in Alzheimer's disease (AD) and behavioral variant frontotemporal dementia (bvFTD) can be similarly impaired, whereas recognition performance is more variable. A potential reason for this variability could be false-positive errors made on recognition trials and whether these errors are due to amnesia per se or a general over-endorsement of recognition items regardless of memory. The current study addressed this issue by analysing recognition performance on the Rey Auditory Verbal Learning Test (RAVLT) in 39 bvFTD, 77 AD and 61 control participants from two centers (India, Australia), as well as disinhibition assessed using the Hayling test. Whereas both AD and bvFTD patients were comparably impaired on delayed recall, bvFTD patients showed intact recognition performance in terms of the number of correct hits. However, both patient groups endorsed significantly more false-positives than controls, and bvFTD and AD patients scored equally poorly on a sensitivity index (correct hits-false-positives). Furthermore, measures of disinhibition were significantly associated with false positives in both groups, with a stronger relationship with false-positives in bvFTD. Voxel-based morphometry analyses revealed similar neural correlates of false positive endorsement across bvFTD and AD, with both patient groups showing involvement of prefrontal and Papez circuitry regions, such as medial temporal and thalamic regions, and a DTI analysis detected an emerging but non-significant trend between false positives and decreased fornix integrity in bvFTD only. These findings suggest that false-positive errors on recognition tests relate to similar mechanisms in bvFTD and AD, reflecting deficits in episodic memory processes and disinhibition. These findings highlight that current memory tests are not sufficient to accurately distinguish between bvFTD and AD patients.

[False positive results or what's the probability that a significant P-value indicates a true effect?

PubMed

Cucherat, Michel; Laporte, Silvy

2017-09-01

The use of statistical test is central in the clinical trial. At the statistical level, obtaining a P<0.05 allows to claim the effectiveness of the new studied treatment. However, given its underlying mathematical logic the concept of "P value" is often misinterpreted. It is often assimilated, mistakenly, to the likelihood that treatment is ineffective. Actually the "P value" gives an indirect information about the plausibility of the existence of treatment effect. With "P<0.05", the probability that the treatment is effective may vary depending on other statistical parameters which are the alpha level of risk, the power of the study and especially the a priori probability of the existence of treatment effect. A "P<0.05" does not always produce the same degree of certainty. Thus there exist situations where the risk of a result "P<0.05" is in reality a false positive is very high. This is the case if the power is low, if there is an inflation of the alpha risk or if the result is exploratory or chance discoveries. This possibility is important to take into consideration when interpreting the results of clinical trials in order to avoid pushing ahead significant results in appearance, but which are likely to be actually false positive results. Copyright © 2017 Société française de pharmacologie et de thérapeutique. Published by Elsevier Masson SAS. All rights reserved.

DNA sequencing of maternal plasma reliably identifies trisomy 18 and trisomy 13 as well as Down syndrome: an international collaborative study

PubMed Central

Palomaki, Glenn E.; Deciu, Cosmin; Kloza, Edward M.; Lambert-Messerlian, Geralyn M.; Haddow, James E.; Neveux, Louis M.; Ehrich, Mathias; van den Boom, Dirk; Bombard, Allan T.; Grody, Wayne W.; Nelson, Stanley F.; Canick, Jacob A.

2012-01-01

Purpose: To determine whether maternal plasma cell–free DNA sequencing can effectively identify trisomy 18 and 13. Methods: Sixty-two pregnancies with trisomy 18 and 12 with trisomy 13 were selected from a cohort of 4,664 pregnancies along with matched euploid controls (including 212 additional Down syndrome and matched controls already reported), and their samples tested using a laboratory-developed, next-generation sequencing test. Interpretation of the results for chromosome 18 and 13 included adjustment for CG content bias. Results: Among the 99.1% of samples interpreted (1,971/1,988), observed trisomy 18 and 13 detection rates were 100% (59/59) and 91.7% (11/12) at false-positive rates of 0.28% and 0.97%, respectively. Among the 17 samples without an interpretation, three were trisomy 18. If z-score cutoffs for trisomy 18 and 13 were raised slightly, the overall false-positive rates for the three aneuploidies could be as low as 0.1% (2/1,688) at an overall detection rate of 98.9% (280/283) for common aneuploidies. An independent academic laboratory confirmed performance in a subset. Conclusion: Among high-risk pregnancies, sequencing circulating cell–free DNA detects nearly all cases of Down syndrome, trisomy 18, and trisomy 13, at a low false-positive rate. This can potentially reduce invasive diagnostic procedures and related fetal losses by 95%. Evidence supports clinical testing for these aneuploidies. PMID:22281937

Simultaneous Genotype Calling and Haplotype Phasing Improves Genotype Accuracy and Reduces False-Positive Associations for Genome-wide Association Studies

PubMed Central

Browning, Brian L.; Yu, Zhaoxia

2009-01-01

We present a novel method for simultaneous genotype calling and haplotype-phase inference. Our method employs the computationally efficient BEAGLE haplotype-frequency model, which can be applied to large-scale studies with millions of markers and thousands of samples. We compare genotype calls made with our method to genotype calls made with the BIRDSEED, CHIAMO, GenCall, and ILLUMINUS genotype-calling methods, using genotype data from the Illumina 550K and Affymetrix 500K arrays. We show that our method has higher genotype-call accuracy and yields fewer uncalled genotypes than competing methods. We perform single-marker analysis of data from the Wellcome Trust Case Control Consortium bipolar disorder and type 2 diabetes studies. For bipolar disorder, the genotype calls in the original study yield 25 markers with apparent false-positive association with bipolar disorder at a p < 10−7 significance level, whereas genotype calls made with our method yield no associated markers at this significance threshold. Conversely, for markers with replicated association with type 2 diabetes, there is good concordance between genotype calls used in the original study and calls made by our method. Results from single-marker and haplotypic analysis of our method's genotype calls for the bipolar disorder study indicate that our method is highly effective at eliminating genotyping artifacts that cause false-positive associations in genome-wide association studies. Our new genotype-calling methods are implemented in the BEAGLE and BEAGLECALL software packages. PMID:19931040

Comment on Hall et al. (2017), "How to Choose Between Measures of Tinnitus Loudness for Clinical Research? A Report on the Reliability and Validity of an Investigator-Administered Test and a Patient-Reported Measure Using Baseline Data Collected in a Phase IIa Drug Trial".

PubMed

Sabour, Siamak

2018-03-08

The purpose of this letter, in response to Hall, Mehta, and Fackrell (2017), is to provide important knowledge about methodology and statistical issues in assessing the reliability and validity of an audiologist-administered tinnitus loudness matching test and a patient-reported tinnitus loudness rating. The author uses reference textbooks and published articles regarding scientific assessment of the validity and reliability of a clinical test to discuss the statistical test and the methodological approach in assessing validity and reliability in clinical research. Depending on the type of the variable (qualitative or quantitative), well-known statistical tests can be applied to assess reliability and validity. The qualitative variables of sensitivity, specificity, positive predictive value, negative predictive value, false positive and false negative rates, likelihood ratio positive and likelihood ratio negative, as well as odds ratio (i.e., ratio of true to false results), are the most appropriate estimates to evaluate validity of a test compared to a gold standard. In the case of quantitative variables, depending on distribution of the variable, Pearson r or Spearman rho can be applied. Diagnostic accuracy (validity) and diagnostic precision (reliability or agreement) are two completely different methodological issues. Depending on the type of the variable (qualitative or quantitative), well-known statistical tests can be applied to assess validity.

Analysis of binary responses with outcome-specific misclassification probability in genome-wide association studies.

PubMed

Rekaya, Romdhane; Smith, Shannon; Hay, El Hamidi; Farhat, Nourhene; Aggrey, Samuel E

2016-01-01

Errors in the binary status of some response traits are frequent in human, animal, and plant applications. These error rates tend to differ between cases and controls because diagnostic and screening tests have different sensitivity and specificity. This increases the inaccuracies of classifying individuals into correct groups, giving rise to both false-positive and false-negative cases. The analysis of these noisy binary responses due to misclassification will undoubtedly reduce the statistical power of genome-wide association studies (GWAS). A threshold model that accommodates varying diagnostic errors between cases and controls was investigated. A simulation study was carried out where several binary data sets (case-control) were generated with varying effects for the most influential single nucleotide polymorphisms (SNPs) and different diagnostic error rate for cases and controls. Each simulated data set consisted of 2000 individuals. Ignoring misclassification resulted in biased estimates of true influential SNP effects and inflated estimates for true noninfluential markers. A substantial reduction in bias and increase in accuracy ranging from 12% to 32% was observed when the misclassification procedure was invoked. In fact, the majority of influential SNPs that were not identified using the noisy data were captured using the proposed method. Additionally, truly misclassified binary records were identified with high probability using the proposed method. The superiority of the proposed method was maintained across different simulation parameters (misclassification rates and odds ratios) attesting to its robustness.

Posterior mediastinal ganglioneuroma with peripheral replacement by white and brown adipocytes resulting in diagnostic fallacy from a false-positive 18F-2-fluoro-2-deoxyglucose-positron emission tomography finding: a case report

PubMed Central

2014-01-01

Introduction Ganglioneuroma is a rare tumor in the posterior mediastinum; fat-containing ganglioneuromas are rarely reported. The present case report documents a brown fat-containing, posterior mediastinal ganglioneuroma, which has not been reported previously. Radiological examination, in particular 18F-2-fluoro-2-deoxyglucose-positron emission tomography, suggested that the tumor had low-grade malignant potential. This led to uncertainty at preoperative diagnosis. Case presentation An asymptomatic 66-year-old Japanese woman with no significant past medical history was referred for the evaluation of a posterior mediastinal mass. Although its size had not changed in the past 5 years, a malignant lipomatous tumor could not be excluded due to the presence of intratumoral fat and increased 18F-2-fluoro-2-deoxyglucose uptake observed by positron emission tomography imaging. A computed tomography-guided core-needle biopsy revealed a mixture of mature adipocytes, spindle-shaped cells, and fibrotic stroma. Definite diagnosis was not possible, and surgical resection was performed. Three years after the surgery, she remains disease-free. Conclusions Histological diagnosis of the surgically resected mass confirmed ganglioneuroma with substantial amounts of white and brown adipose tissues in peripheral areas. The existence of both ganglion cells and brown fat tissue intensified the accumulation of 18F-2-fluoro-2-deoxyglucose, resulting in a false-positive result by positron emission tomography. Considering this, ganglioneuroma should not be excluded either clinically or pathologically in fat-containing, posterior mediastinal tumors. PMID:25319096

Age-specific application of neutrophil-to-lymphocyte ratio in meningitis: a nationwide study.

PubMed

Mentis, A-F A; Kyprianou, M A; Tzanakaki, G

2017-09-01

Cerebrospinal fluid (CSF) neutrophil counts and neutrophil-to-lymphocyte ratio (NLR) are useful in distinguishing bacterial and viral meningitis. Given that meningitis is clinically heterogeneous with regard to age, here we investigated the validity of the CSF NLR and neutrophil assay according to age group. Data from the nationwide referral of >4,000 meningitis cases to the Hellenic Meningitis Reference Laboratory between 2006 and 2013 were examined. CSF NLR and neutrophil counts were stratified according to age, and assay performance was determined using previous cut-off values of 2 and 287 cells/μl for CSF NLR and neutrophils respectively. The distribution of bacterial versus viral meningitis was heterogenous across age groups, with a low proportion of bacterial meningitis in patients aged 5-14. CSF neutrophil count and NLR were significantly more discriminatory for bacterial meningitis in patients aged over 14 years than those aged 0-14. The odds ratio (OR), sensitivity, specificity and positive predictive value (PPV) were significantly higher in older patients for both biomarkers. When combined, the false-positive and false-negative detection of bacterial meningitis was 3.9 and 8.5% respectively, and the OR of 262.2 was 2.5-fold greater than expected from a multiplicative effect alone in patients aged >14 years. Care is required when applying diagnostic tests for meningitis in different age groups because of patient heterogeneity. This is the first description of the age distribution of meningitis cases in Greece, and knowledge of the age-related distribution of neutrophils and NLR in meningitis cases could help towards developing age-specific meningitis diagnostic assays.

Accuracy of a Plasmodium falciparum specific histidine-rich protein 2 rapid diagnostic test in the context of the presence of non-malaria fevers, prior anti-malarial use and seasonal malaria transmission.

PubMed

Kiemde, Francois; Bonko, Massa Dit Achille; Tahita, Marc Christian; Lompo, Palpouguini; Rouamba, Toussaint; Tinto, Halidou; van Hensbroek, Michael Boele; Mens, Petra F; Schallig, Henk D F H

2017-07-20

It remains challenging to distinguish malaria from other fever causing infections, as a positive rapid diagnostic test does not always signify a true active malaria infection. This study was designed to determine the influence of other causes of fever, prior anti-malarial treatment, and a possible seasonality of the performance of a PfHRP2 RDT for the diagnosis of malaria in children under-5 years of age living in a malaria endemic area. A prospective etiology study was conducted in 2015 among febrile children under 5 years of age in Burkina Faso. In order to assess the influence of other febrile illnesses, prior treatment and seasonality on the performance of a PfHRP2 RDT in diagnosing malaria, the RDT results were compared with the gold standard (expert microscopic diagnosis of Plasmodium falciparum) and test results were analysed by assuming that prior anti-malarial use and bacterial/viral infection status would have been known prior to testing. To assess bacterial and viral infection status blood, urine and stool samples were analysed. In total 683 blood samples were analysed with microscopy and RDT-PfHRP2. Plasmodium falciparum malaria was diagnosed in 49.8% (340/683) by microscopy compared to 69.5% (475/683) by RDT-PfHRP2. The RDT-PfHRP2 reported 29.7% (141/475) false positive results and 1.8% (6/340) false negative cases. The RDT-PfHRP2 had a high sensitivity (98.2%) and negative predictive value (97.1%), but a low specificity (58.9%) and positive predictive value (70.3%). Almost 50% of the alternative cause of fever were diagnosed by laboratory testing in the RDT false positive malaria group. The use of a malaria RDT-PfHRP2 in a malaria endemic area may cause misdiagnosis of the actual cause of fever due to false positive test results. The development of a practical diagnostic tool to screen for other causes of fever in malaria endemic areas is required to save lives.

Multislice CT Angiography in Renal Artery Stent Evaluation: Prospective Comparison with Intra-Arterial Digital Subtraction Angiography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raza, Syed A.; Chughtai, Aamer R.; Wahba, Mona

2004-01-15

Purpose: To assess the role of multislice computed tomography angiography (MCTA) in the evaluation of renal artery stents, using intra-arterial digital subtraction angiography (DSA) as the gold standard. Methods: Twenty consecutive patients (15 men, 5 women) with 23 renal artery stents prospectively underwent both MCTA and DSA. Axial images, multiplanar reconstructions and maximum intensity projection images were used for diagnosis. The MCTA and DSA images were each interpreted without reference to the result of the other investigation. Results:The three cases of restenosis on DSA were detected correctly by MCTA; in 19 cases where MCTA showed a fully patent stent, themore » DSA was also negative. Sensitivity and negative predictive value (NPV) of MCTA were therefore 100%. In four cases, MCTA showed apparently minimal disease which was not shown on DSA. These cases are taken as false positive giving a specificity of 80% and a positive predictive value of 43%. Conclusion: The high sensitivity and NPV suggest MCTA may be useful as a noninvasive screen for renal artery stentrestenosis. MCTA detected mild disease in a few patients which was not confirmed on angiography.« less

Diurnal rhythm and concordance between objective and subjective hot flashes: the Hilo Women's Health Study.

PubMed

Sievert, Lynnette L; Reza, Angela; Mills, Phoebe; Morrison, Lynn; Rahberg, Nichole; Goodloe, Amber; Sutherland, Michael; Brown, Daniel E

2010-01-01

The aims of this study were to test for a diurnal pattern in hot flashes in a multiethnic population living in a hot, humid environment and to examine the rates of concordance between objective and subjective measures of hot flashes using ambulatory and laboratory measures. Study participants aged 45 to 55 years were recruited from the general population of Hilo, HI. Women wore a Biolog hot flash monitor (UFI, Morro Bay, CA), kept a diary for 24 hours, and also participated in 3-hour laboratory measures (n = 199). Diurnal patterns were assessed using polynomial regression. For each woman, objectively recorded hot flashes that matched subjective experience were treated as true-positive readings. Subjective hot flashes were considered the standard for computing false-positive and false-negative readings. True-positive, false-positive, and false-negative readings were compared across ethnic groups by chi analyses. Frequencies of sternal, nuchal, and subjective hot flashes peaked at 1500 +/- 1 hours with no difference by ethnicity. Laboratory results supported the pattern seen in ambulatory monitoring. Sternal and nuchal monitoring showed the same frequency of true-positive measures, but nonsternal electrodes picked up more false-positive readings. Laboratory monitoring showed very low frequencies of false negatives. There were no ethnic differences in the frequency of true-positive or false-positive measures. Women of European descent were more likely to report hot flashes that were not objectively demonstrated (false-negative measures). The diurnal pattern and peak in hot flash occurrence in the hot humid environment of Hilo were similar to results from more temperate environments. Lack of variation in sternal versus nonsternal measures and in true-positive measures across ethnicities suggests no appreciable effect of population variation in sweating patterns.

Diurnal rhythm and concordance between objective and subjective hot flashes: The Hilo Women’s Health Study

PubMed Central

Sievert, Lynnette L.; Reza, Angela; Mills, Phoebe; Morrison, Lynn; Rahberg, Nichole; Goodloe, Amber; Sutherland, Michael; Brown, Daniel E.

2010-01-01

Objective To test for a diurnal pattern in hot flashes in a multi-ethnic population living in a hot, humid environment. To examine rates of concordance between objective and subjective measures of hot flashes using ambulatory and laboratory measures. Methods Study participants aged 45–55 were recruited from the general population of Hilo, Hawaii. Women wore a Biolog hot flash monitor, kept a diary for 24-hours, and also participated in 3-hour laboratory measures (n=199). Diurnal patterns were assessed using polynomial regression. For each woman, objectively recorded hot flashes that matched subjective experience were treated as true positive readings. Subjective hot flashes were considered the standard for computing false positive and false negative readings. True positive, false positive, and false negative readings were compared across ethnic groups by chi-square analyses. Results Frequencies of sternal, nuchal and subjective hot flashes peaked at 15:00 ± 1 hour with no difference by ethnicity. Laboratory results supported the pattern seen in ambulatory monitoring. Sternal and nuchal monitoring showed the same frequency of true positive measures, but non-sternal electrodes picked up more false positive readings. Laboratory monitoring showed very low frequencies of false negatives. There were no ethnic differences in the frequency of true positive or false positive measures. Women of European descent were more likely to report hot flashes that were not objectively demonstrated (false negative measures). Conclusions The diurnal pattern and peak in hot flash occurrence in the hot humid environment of Hilo was similar to results from more temperate environments. Lack of variation in sternal vs. non-sternal measures, and in true positive measures across ethnicities suggests no appreciable effect of population variation in sweating patterns. PMID:20220538

Forensic child sexual abuse evaluations: assessing subjectivity and bias in professional judgements.

PubMed

Everson, Mark D; Sandoval, Jose Miguel

2011-04-01

Evaluators examining the same evidence often arrive at substantially different conclusions in forensic assessments of child sexual abuse (CSA). This study attempts to identify and quantify subjective factors that contribute to such disagreements so that interventions can be devised to improve the reliability of case decisions. Participants included 1106 professionals in the field of child maltreatment representing a range of professional positions or job titles and years of experience. Each completed the Child Forensic Attitude Scale (CFAS), a 28-item survey assessing 3 forensic attitudes believed to influence professional judgments about CSA allegations: emphasis-on-sensitivity (i.e., a focus on minimizing false negatives or errors of undercalling abuse); emphasis-on-specificity (i.e., a focus on minimizing false positives or errors of overcalling abuse); and skepticism toward child and adolescent reports of CSA. A subset of 605 professionals also participated in 1 of 3 diverse decision exercises to assess the influence of the 3 forensic attitudes on ratings of case credibility. Exploratory factor analysis identified 4 factors or attitude subscales that corresponded closely with the original CFAS scales: 2 subscales for emphasis-on-sensitivity and 1 each for emphasis-on-specificity and skepticism. Attitude subscale scores differed significantly by sample source (in-state trainings vs. national conferences), gender, years of experience, and professional position, with Child Protective Service workers unexpectedly more concerned about overcalling abuse and more skeptical of child disclosures than other professionals-a pattern of scores associated with an increased probability of disbelieving CSA allegations. The 3 decision exercises offered validation of the attitude subscales as predictors of professional ratings of case credibility, with adjusted R(2)s for the three exercises ranging from .06 to .24, suggesting highly variable effect sizes. Evaluator disagreements about CSA allegations can be explained, in part, by individual differences in 3 attitudes related to forensic decision-making: emphasis-on-sensitivity, emphasis-on-specificity, and skepticism toward child reports of abuse. These attitudes operate as predispositions or biases toward viewing CSA allegations as likely true or likely false. Several strategies for curbing the influence of subjective factors are highlighted including self-awareness of personal biases and team approaches to assessment. Copyright © 2011 Elsevier Ltd. All rights reserved.

False positive circumsporozoite protein ELISA: a challenge for the estimation of the entomological inoculation rate of malaria and for vector incrimination

PubMed Central

2011-01-01

Background The entomological inoculation rate (EIR) is an important indicator in estimating malaria transmission and the impact of vector control. To assess the EIR, the enzyme-linked immunosorbent assay (ELISA) to detect the circumsporozoite protein (CSP) is increasingly used. However, several studies have reported false positive results in this ELISA. The false positive results could lead to an overestimation of the EIR. The aim of present study was to estimate the level of false positivity among different anopheline species in Cambodia and Vietnam and to check for the presence of other parasites that might interact with the anti-CSP monoclonal antibodies. Methods Mosquitoes collected in Cambodia and Vietnam were identified and tested for the presence of sporozoites in head and thorax by using CSP-ELISA. ELISA positive samples were confirmed by a Plasmodium specific PCR. False positive mosquitoes were checked by PCR for the presence of parasites belonging to the Haemosporidia, Trypanosomatidae, Piroplasmida, and Haemogregarines. The heat-stability and the presence of the cross-reacting antigen in the abdomen of the mosquitoes were also checked. Results Specimens (N = 16,160) of seven anopheline species were tested by CSP-ELISA for Plasmodium falciparum and Plasmodium vivax (Pv210 and Pv247). Two new vector species were identified for the region: Anopheles pampanai (P. vivax) and Anopheles barbirostris (Plasmodium malariae). In 88% (155/176) of the mosquitoes found positive with the P. falciparum CSP-ELISA, the presence of Plasmodium sporozoites could not be confirmed by PCR. This percentage was much lower (28% or 5/18) for P. vivax CSP-ELISAs. False positive CSP-ELISA results were associated with zoophilic mosquito species. None of the targeted parasites could be detected in these CSP-ELISA false positive mosquitoes. The ELISA reacting antigen of P. falciparum was heat-stable in CSP-ELISA true positive specimens, but not in the false positives. The heat-unstable cross-reacting antigen is mainly present in head and thorax and almost absent in the abdomens (4 out of 147) of the false positive specimens. Conclusion The CSP-ELISA can considerably overestimate the EIR, particularly for P. falciparum and for zoophilic species. The heat-unstable cross-reacting antigen in false positives remains unknown. Therefore it is highly recommended to confirm all positive CSP-ELISA results, either by re-analysing the heated ELISA lysate (100°C, 10 min), or by performing Plasmodium specific PCR followed if possible by sequencing of the amplicons for Plasmodium species determination. PMID:21767376

77 FR 48045 - Supplemental Nutrition Assistance Program: Disqualified Recipient Reporting and Computer Matching...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-13

... false positive match rate of 10 percent. Making the match mandatory for the States who did not perform... number of prisoners from 1995 to 2013 and assumed a 10 percent false positive match rate. Finally, we... matches are false positives. We estimate that mandatory matches at certification will identify an...

Propionibacterium acnes infection in shoulder arthroscopy patients with postoperative pain.

PubMed

Horneff, John G; Hsu, Jason E; Voleti, Pramod B; O'Donnell, Judith; Huffman, G Russell

2015-06-01

Recent studies have identified Propionibacterium acnes as the causal organism in an increasing number of postoperative shoulder infections. Most reports have found a high rate of P acnes infection after open surgery, particularly shoulder arthroplasty. However, there are limited data regarding P acnes infections after shoulder arthroscopy. We prospectively collected data on all shoulder arthroscopies performed by the senior author from January 1, 2009, until April 1, 2013. Cultures were taken in all revision shoulder arthroscopy cases performed for pain, stiffness, or weakness. In addition, 2 cultures were taken from each of a cohort of 32 primary shoulder arthroscopy cases without concern for infection to determine the false-positive rate. A total of 1,591 shoulder arthroscopies were performed during this period, 68 (4.3%) of which were revision procedures performed for pain, stiffness, or weakness. A total of 20 revision arthroscopies (29.4%) had positive culture findings, and 16 (23.5%) were positive for P acnes. In the control group, 1 patient (3.2%) had P acnes growth. The rate of P acnes infection in patients undergoing revision shoulder arthroscopy is higher than previously published and should be considered in cases characterized by refractory postoperative pain and stiffness. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Combined use of fatty acid ethyl esters and ethyl glucuronide in hair for diagnosis of alcohol abuse: interpretation and advantages.

PubMed

Pragst, F; Rothe, M; Moench, B; Hastedt, M; Herre, S; Simmert, D

2010-03-20

In this study the combined use of fatty acid ethyl esters (FAEE) and ethyl glucuronide (EtG) for diagnoses of chronically excessive alcohol abuse is investigated at 174 hair samples from driving ability examination, workplace testing and child custody cases for family courts and evaluated with respect to the basics of interpretation. Using the cut-off values of 0.50 ng/mg for FAEE and 25 pg/mg for EtG, both markers were in agreement in 75% of the cases with 103 negative and 28 positive results and there were 30 cases with FAEE positive and EtG negative and 13 cases with FAEE negative and EtG positive. As the theoretical basis of interpretation, the pharmacokinetics of FAEE and EtG is reviewed for all steps between drinking of ethanol to incorporation in hair with particular attention to relationships between alcohol dose and concentrations in hair. It is shown that the concentrations of both markers are essentially determined by the area under the ethanol concentration in blood vs. time curve AUC(EtOH), despite large inter-individual variations. It is demonstrated by calculation of AUC(EtOH) on monthly basis for moderate, risky and heavy drinking that AUC(EtOH) increases very strongly in the range between 60 and 120 g ethanol per day. This specific feature which is caused by the zero-order elimination of ethanol is a favorable prerequisite for a high discrimination power of the hair testing for alcohol abuse. From the consideration of the different profiles of FAEE and EtG along the hair and in agreement with the literature survey, a standardized hair segment 0-3 cm is proposed with cut-off values of 0.5 ng/mg for FAEE and 30 pg/mg for EtG. This improves also the agreement between FAEE and EtG results in the cases of the present study. A scheme for combined interpretation of FAEE and EtG is proposed which uses the levels of abstinence and the double of the cut-off values as criteria in addition to the cut-off's. Considering the large variations in the relationship between ethanol dose and FAEE and EtG concentrations in hair, the combined use of both parameters strongly increases the accuracy of the diagnosis by mutual confirmation and identification of false positive or false negative results due to biological variations or analytical errors. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.

Can imaging criteria distinguish enchondroma from grade 1 chondrosarcoma?

PubMed

Crim, Julia; Schmidt, Robert; Layfield, Lester; Hanrahan, Christopher; Manaster, Betty Jean

2015-11-01

To minimize systematic bias and optimize agreement on imaging criteria in order to better define the accuracy of imaging criteria in the diagnosis of grade 1 chondrosarcoma. Study was IRB-approved and HIPAA compliant; informed consent was waived. Records were reviewed and disclosed 53 cases (38 women, 15 men ages 21-76) which were diagnosed as enchondroma or grade 1 chondrosarcoma and had available radiographs, contrast-enhanced MRI, and definitive diagnosis by histology or 5-year follow-up. 2 MSK radiologists read the studies independently after a session where they agreed on criteria for malignancy. Interobserver variability was determined as raw variability and with the kappa statistic. Accuracy was determined compared to final diagnosis. Reliability of imaging features of chondrosarcoma was determined using regression analysis. The correct diagnosis of enchondroma was made on radiographs in 43 (67.2%) of readings, and on MRI in 37/64 (57.8%). The correct diagnosis of chondrosarcoma was made on radiographs in 5/24 (20.8%) of readings, and on MRI in 14/24 (57.8%). A diagnosis of borderline lesion was made in 19/64 (29.7%) of enchondromas on radiographs and 18/64 (28.1%) on MRI. The false positive rate of radiographs for chondrosarcoma was 2/64 (3.1%) and the false positive rate of MRI was 9/64 (14.1%). There was substantial interobserver variability. Cortical thickening and bone expansion were rare but specific signs of chondrosarcoma. Both radiographs and MRI have limitations in the evaluation of low-grade cartilage lesions. MRI has an increased rate of both true-positive and false-positive diagnosis compared to radiographs. Differences in the findings of this study compared to previous literature may reflect the influence of systematic biases. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Azithromycin treatment failure for Chlamydia trachomatis among heterosexual men with nongonococcal urethritis

PubMed Central

Kissinger, Patricia; White, Scott; Manhart, Lisa E.; Schwebke, Jane; Taylor, Stephanie N; Mena, Leandro; Khosropour, Christine M; Wilcox, Larissa; Schmidt, Norine; Martin, David H

2016-01-01

Background Three recent prospective studies have suggested that the 1 g dose of azithromycin for Chlamydia trachomatis (Ct) was less effective than expected, reporting a wide range of treatment failure rates (5.8%–22.6%). Reasons for the disparate results could be attributed to geographic or methodological differences. The purpose of this study was to re-examine the studies and attempt to harmonize methodologies to reduce misclassification as a result of false positives from early test-of-cure (TOC) or reinfection as a result of sexual exposure rather than treatment failure. Methods Men who had sex with women, who received 1 g azithromycin under directly observed therapy (DOT) for presumptive treatment of nongonococcal urethritis (NGU) with confirmed Ct were included. Baseline screening was performed on urethral swabs or urine and TOC screening was performed on urine using nucleic acid amplification tests (NAAT). Post-treatment vaginal sexual exposure was elicited at TOC. Data from the three studies was obtained and re-analyzed. Rates of Ct re-test positive were examined for all cases and a sensitivity analysis was conducted to either reclassify potential false positives/reinfections as negative or remove them from the analysis. Results The crude treatment failure rate was 12.8% (31/242). The rate when potential false positives/reinfections were reclassified as negative was 6.2% (15/242) or when these were excluded from analysis was 10.9% (15/138). Conclusion In these samples of men who have sex with women with Ct-related NGU, azithromycin treatment failure was between 6.2% and 12.8%. This range of failure is lower than previously published but higher than the desired World Health Organization’s target chlamydia treatment failure rate of < 5%. PMID:27631353

Azithromycin Treatment Failure for Chlamydia trachomatis Among Heterosexual Men With Nongonococcal Urethritis.

PubMed

Kissinger, Patricia J; White, Scott; Manhart, Lisa E; Schwebke, Jane; Taylor, Stephanie N; Mena, Leandro; Khosropour, Christine M; Wilcox, Larissa; Schmidt, Norine; Martin, David H

2016-10-01

Three recent prospective studies have suggested that the 1-g dose of azithromycin for Chlamydia trachomatis (Ct) was less effective than expected, reporting a wide range of treatment failure rates (5.8%-22.6%). Reasons for the disparate results could be attributed to geographic or methodological differences. The purpose of this study was to reexamine the studies and attempt to harmonize methodologies to reduce misclassification as a result of false positives from early test-of-cure (TOC) or reinfection as a result of sexual exposure rather than treatment failure. Men who had sex with women, who received 1-g azithromycin under directly observed therapy for presumptive treatment of nongonococcal urethritis with confirmed Ct were included. Baseline screening was performed on urethral swabs or urine, and TOC screening was performed on urine using nucleic acid amplification tests. Posttreatment vaginal sexual exposure was elicited at TOC. Data from the 3 studies were obtained and reanalyzed. Rates of Ct retest positive were examined for all cases, and a sensitivity analysis was conducted to either reclassify potential false positives/reinfections as negative or remove them from the analysis. The crude treatment failure rate was 12.8% (31/242). The rate when potential false positives/reinfections were reclassified as negative was 6.2% (15/242) or when these were excluded from analysis was 10.9% (15/138). In these samples of men who have sex with women with Ct-related nongonococcal urethritis, azithromycin treatment failure was between 6.2% and 12.8%. This range of failure is lower than previously published but higher than the desired World Health Organization's target chlamydia treatment failure rate of < 5%.

Validation of SmartRank: A likelihood ratio software for searching national DNA databases with complex DNA profiles.

PubMed

Benschop, Corina C G; van de Merwe, Linda; de Jong, Jeroen; Vanvooren, Vanessa; Kempenaers, Morgane; Kees van der Beek, C P; Barni, Filippo; Reyes, Eusebio López; Moulin, Léa; Pene, Laurent; Haned, Hinda; Sijen, Titia

2017-07-01

Searching a national DNA database with complex and incomplete profiles usually yields very large numbers of possible matches that can present many candidate suspects to be further investigated by the forensic scientist and/or police. Current practice in most forensic laboratories consists of ordering these 'hits' based on the number of matching alleles with the searched profile. Thus, candidate profiles that share the same number of matching alleles are not differentiated and due to the lack of other ranking criteria for the candidate list it may be difficult to discern a true match from the false positives or notice that all candidates are in fact false positives. SmartRank was developed to put forward only relevant candidates and rank them accordingly. The SmartRank software computes a likelihood ratio (LR) for the searched profile and each profile in the DNA database and ranks database entries above a defined LR threshold according to the calculated LR. In this study, we examined for mixed DNA profiles of variable complexity whether the true donors are retrieved, what the number of false positives above an LR threshold is and the ranking position of the true donors. Using 343 mixed DNA profiles over 750 SmartRank searches were performed. In addition, the performance of SmartRank and CODIS were compared regarding DNA database searches and SmartRank was found complementary to CODIS. We also describe the applicable domain of SmartRank and provide guidelines. The SmartRank software is open-source and freely available. Using the best practice guidelines, SmartRank enables obtaining investigative leads in criminal cases lacking a suspect. Copyright © 2017 Elsevier B.V. All rights reserved.

Detection of Occult Invasion in Melanoma In Situ.

PubMed

Bax, Michael J; Johnson, Timothy M; Harms, Paul W; Schwartz, Jennifer L; Zhao, Lili; Fullen, Douglas R; Chan, May P

2016-11-01

It is unclear why some patients with in situ melanoma develop metastases. Few reports demonstrate occult invasion with immunohistochemistry staining, which were discordant with reports interpreting such staining as false-positive. To investigate the occurrence of occult invasive disease within in situ melanoma by using methods to circumvent potential limitations in prior study designs. Unequivocal in situ melanoma without associated nevi or regression was identified using a consecutive sample of 33 cases plus 1 index case in an academic medical center. After cutting deeper into the most representative tissue block, 3 sequential slides were stained with hematoxylin-eosin (H-E), melanoma antigen (melan-A), and again with H-E. Melan-A-stained slides showing definitive invasion were double-stained with Sry-related HMg-Box gene 10 (SOX10) to confirm the melanocytic nature of the cells of interest. The study evaluated the possibilities of occult invasion detected by immunohistochemistry, sectioning deeper into the tissue block, or both. Slides were independently scored by 3 dermatopathologists with interrater reliability assessed. The study was conducted from January 1, 2012, to July 31, 2014. Assessment of the occurrence of occult invasion, diagnosis of invasion by immunohistochemistry alone vs cutting deeper into the tissue block, and occurrence of false-positive results using immunohistochemistry alone. Occult invasive melanoma was detected in 11 of 33 consecutive cases (33%) of previously diagnosed unequivocal in situ melanoma. Six of 11 melanomas (55%) were diagnosable only by immunohistochemistry. The remaining 5 tumors (45%) were diagnosable by both melan-A and H-E staining, likely as a result of simply cutting deeper into the tissue block. Four cases (12%) showed a few melan-A-positive cells in the dermis, which was insufficient for a diagnosis of invasive melanoma and most consistent on a cytomorphologic basis with occult nevi. Although rare, in situ melanoma may metastasize. Occult microinvasion was demonstrated in up to one-third of the specimens in the present study, which provides a plausible explanation for this adverse event. Thus, history and physical examination including regional lymph nodes, education, and surveillance recommendations should be based on a very low, but not zero, risk of metastasis.

Cardiovascular outcomes of a positive nuclear stress test but negative coronary angiography in a multiethnic male predominant cohort.

PubMed

Addison, Daniel; Singh, Vinita; Okyere-Asante, K; Okafor, Henry

2014-01-01

Patients presenting with chest pain and evidence of functional ischemia by myocardial perfusion imaging (MPI), but lacking commensurate angiographic disease pose a diagnostic and therapeutic dilemma. They are often dismissed as having 'false-positive MPI'. Moreover, a majority of the available long-term outcome data for it has been derived from homogenous female populations. In this study, we sought to evaluate the long-term outcomes of this presentation in a multiethnic male-predominant cohort. We retrospectively identified 47 patients who presented to our institution between 2002 and 2005 with chest pain and evidence of ischemia on MPI, but with no significant angiographic disease on subsequent cardiac catheterization (cases). The occurrence of adverse cardiovascular outcomes (chest pain, congestive heart failure, acute myocardial infarction and stroke) post-index coronary angiogram was tracked. Similar data was collected for 37 patients who also presented with chest pain, but normal MPI over the same period (controls). Overall average follow-up was over 22 months. Fifty-three percent (26/47) of the cases had one or more of the adverse outcomes as compared with 22% (8/37) of controls (P < 0.01). Of these, 13 (50.0%) and 3 (37.5%) were males, respectively. Ischemia on MPI is predictive of long-term adverse cardiovascular outcomes despite normal ('false-negative') coronary angiography. This appears to be gender-neutral.

Empirical evaluation demonstrated importance of validating biomarkers for early detection of cancer in screening settings to limit the number of false-positive findings.

PubMed

Chen, Hongda; Knebel, Phillip; Brenner, Hermann

2016-07-01

Search for biomarkers for early detection of cancer is a very active area of research, but most studies are done in clinical rather than screening settings. We aimed to empirically evaluate the role of study setting for early detection marker identification and validation. A panel of 92 candidate cancer protein markers was measured in 35 clinically identified colorectal cancer patients and 35 colorectal cancer patients identified at screening colonoscopy. For each case group, we selected 38 controls without colorectal neoplasms at screening colonoscopy. Single-, two- and three-marker combinations discriminating cases and controls were identified in each setting and subsequently validated in the alternative setting. In all scenarios, a higher number of predictive biomarkers were initially detected in the clinical setting, but a substantially lower proportion of identified biomarkers could subsequently be confirmed in the screening setting. Confirmation rates were 50.0%, 84.5%, and 74.2% for one-, two-, and three-marker algorithms identified in the screening setting and were 42.9%, 18.6%, and 25.7% for algorithms identified in the clinical setting. Validation of early detection markers of cancer in a true screening setting is important to limit the number of false-positive findings. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Evaluation of information-theoretic similarity measures for content-based retrieval and detection of masses in mammograms.

PubMed

Tourassi, Georgia D; Harrawood, Brian; Singh, Swatee; Lo, Joseph Y; Floyd, Carey E

2007-01-01

The purpose of this study was to evaluate image similarity measures employed in an information-theoretic computer-assisted detection (IT-CAD) scheme. The scheme was developed for content-based retrieval and detection of masses in screening mammograms. The study is aimed toward an interactive clinical paradigm where physicians query the proposed IT-CAD scheme on mammographic locations that are either visually suspicious or indicated as suspicious by other cuing CAD systems. The IT-CAD scheme provides an evidence-based, second opinion for query mammographic locations using a knowledge database of mass and normal cases. In this study, eight entropy-based similarity measures were compared with respect to retrieval precision and detection accuracy using a database of 1820 mammographic regions of interest. The IT-CAD scheme was then validated on a separate database for false positive reduction of progressively more challenging visual cues generated by an existing, in-house mass detection system. The study showed that the image similarity measures fall into one of two categories; one category is better suited to the retrieval of semantically similar cases while the second is more effective with knowledge-based decisions regarding the presence of a true mass in the query location. In addition, the IT-CAD scheme yielded a substantial reduction in false-positive detections while maintaining high detection rate for malignant masses.

Test set readings predict clinical performance to a limited extent: preliminary findings

NASA Astrophysics Data System (ADS)

Soh, BaoLin P.; Lee, Warwick M.; Kench, Peter L.; Reed, Warren M.; McEntee, Mark F.; Brennan, Patrick C.

2013-03-01

Aim: To investigate the level of agreement between test sets and actual clinical reading Background: The performance of screen readers in detecting breast cancer is being assessed in some countries by using mammographic test sets. However, previous studies have provided little evidence that performance assessed by test sets strongly correlate to performance in clinical reading. Methods: Five clinicians from BreastScreen New South Wales participated in this study. Each clinician was asked to read 200 de-identified mammographic examinations gathered from their own case history within the BreastScreen NSW Digital Imaging Library. All test sets were designed with specific proportions of true positive, true negative, false positive and false negative examinations from the previous actual clinical reads of each reader. A prior mammogram examination for comparison (when available) was also provided for each case. Results: Preliminary analyses have shown that there is a moderate level of agreement (Kappa 0.42-0.56, p < 0.001) between laboratory test sets and actual clinical reading. In addition, a mean increase of 38% in sensitivity in the laboratory test sets as compared to their actual clinical readings was demonstrated. Specificity is similar between the laboratory test sets and actual clinical reading. Conclusion: This study demonstrated a moderate level of agreement between actual clinical reading and test set reading, which suggests that test sets have a role in reflecting clinical performance.

The value of the first trimester ultrasound in the era of cell free DNA screening.

PubMed

Rao, Rashmi R; Valderramos, Stephanie G; Silverman, Neil S; Han, Christina S; Platt, Lawrence D

2016-12-01

To describe the clinically relevant findings detected by the first trimester ultrasound (FTU) and to determine the additional value of the FTU compared to cell free DNA (cfDNA) alone. Retrospective cohort study of patients undergoing a FTU at a maternal-fetal medicine referral practice. Fetal, gynecologic, and placental findings detected by ultrasound were analyzed with available cfDNA and diagnostic testing results. A subgroup analysis of positive ultrasound findings and cfDNA results was performed to assess the additional benefit of ultrasound evaluation in FT prenatal screening. There were 1906 FTU between 1 October 2013 and 1 October 2014. CfDNA results were available for 959 (50%) patients. FTU detected: 42 fetal (2.2%), 286 gynecologic (15.0%), and 317 placental (16.6%) findings. CfDNA results were discordant with invasive testing results in 8/61 cases (13%) and with ultrasound findings in 18/42 (42%) cases. There were six false positive and two false negative cfDNA results confirmed by diagnostic testing. Subgroup analysis revealed that cfDNA as the sole method of prenatal screening in the FT would miss 95% of the fetal findings detected with ultrasound. The comprehensive FTU provides valuable clinical information about fetal and maternal anatomy that cannot be detected with cfDNA alone. © 2016 John Wiley & Sons, Ltd. © 2016 John Wiley & Sons, Ltd.

Development of an Expert System as a Diagnostic Support of Cervical Cancer in Atypical Glandular Cells, Based on Fuzzy Logics and Image Interpretation

PubMed Central

Domínguez Hernández, Karem R.; Aguilar Lasserre, Alberto A.; Posada Gómez, Rubén; Palet Guzmán, José A.; González Sánchez, Blanca E.

2013-01-01

Cervical cancer is the second largest cause of death among women worldwide. Nowadays, this disease is preventable and curable at low cost and low risk when an accurate diagnosis is done in due time, since it is the neoplasm with the highest prevention potential. This work describes the development of an expert system able to provide a diagnosis to cervical neoplasia (CN) precursor injuries through the integration of fuzzy logics and image interpretation techniques. The key contribution of this research focuses on atypical cases, specifically on atypical glandular cells (AGC). The expert system consists of 3 phases: (1) risk diagnosis which consists of the interpretation of a patient's clinical background and the risks for contracting CN according to specialists; (2) cytology images detection which consists of image interpretation (IM) and the Bethesda system for cytology interpretation, and (3) determination of cancer precursor injuries which consists of in retrieving the information from the prior phases and integrating the expert system by means of a fuzzy logics (FL) model. During the validation stage of the system, 21 already diagnosed cases were tested with a positive correlation in which 100% effectiveness was obtained. The main contribution of this work relies on the reduction of false positives and false negatives by providing a more accurate diagnosis for CN. PMID:23690881

Point-of-Care Ultrasound: Sonographic Posterior Fat Pad Sign: A Case Report and Brief Literature Review.

PubMed

Okumura, Yoshito; Maldonado, Nestor; Lennon, Kyle; McCarty, Bryan; Underwood, Philipp; Nelson, Mathew

2017-07-01

Diagnosis of elbow fracture can sometimes be difficult with plain radiography due to overlapping bones, growth plates, and maturing bones in the pediatric population. The radiographic posterior fat pad (PFP) sign is one of the frequently referenced indirect signs of an occult elbow fracture. This sign can be falsely negative if the sign is subtle, and can be falsely positive when the position of the elbow is not flexed at 90 degrees. We discuss a case in which sonographic PFP sign helped to diagnose an elbow fracture. A 57-year-old female presented to the emergency department (ED) after a fall on an outstretched hand. The point-of-care ultrasound (POCUS) was completed identifying an elevated PFP and an anechoic joint fluid collection with innumerous floating hyperechogenic spicules visualized in the olecranon fossa. Diagnosis of a radial head fracture was later confirmed by plain radiograph. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: The increase in use and availability of POCUS in the ED makes this a very practical application. Our ability to rapidly perform the ultrasound of the elbow may allow us a more rapid diagnosis of pathology, as well as provide a way to further triage our patients. With time, it may even allow us to avoid routine use of plain radiography. Copyright © 2017 Elsevier Inc. All rights reserved.

Evaluation of information-theoretic similarity measures for content-based retrieval and detection of masses in mammograms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tourassi, Georgia D.; Harrawood, Brian; Singh, Swatee

The purpose of this study was to evaluate image similarity measures employed in an information-theoretic computer-assisted detection (IT-CAD) scheme. The scheme was developed for content-based retrieval and detection of masses in screening mammograms. The study is aimed toward an interactive clinical paradigm where physicians query the proposed IT-CAD scheme on mammographic locations that are either visually suspicious or indicated as suspicious by other cuing CAD systems. The IT-CAD scheme provides an evidence-based, second opinion for query mammographic locations using a knowledge database of mass and normal cases. In this study, eight entropy-based similarity measures were compared with respect to retrievalmore » precision and detection accuracy using a database of 1820 mammographic regions of interest. The IT-CAD scheme was then validated on a separate database for false positive reduction of progressively more challenging visual cues generated by an existing, in-house mass detection system. The study showed that the image similarity measures fall into one of two categories; one category is better suited to the retrieval of semantically similar cases while the second is more effective with knowledge-based decisions regarding the presence of a true mass in the query location. In addition, the IT-CAD scheme yielded a substantial reduction in false-positive detections while maintaining high detection rate for malignant masses.« less

Bladder cancer diagnosis with CT urography: test characteristics and reasons for false-positive and false-negative results.

PubMed

Trinh, Tony W; Glazer, Daniel I; Sadow, Cheryl A; Sahni, V Anik; Geller, Nina L; Silverman, Stuart G

2018-03-01

To determine test characteristics of CT urography for detecting bladder cancer in patients with hematuria and those undergoing surveillance, and to analyze reasons for false-positive and false-negative results. A HIPAA-compliant, IRB-approved retrospective review of reports from 1623 CT urograms between 10/2010 and 12/31/2013 was performed. 710 examinations for hematuria or bladder cancer history were compared to cystoscopy performed within 6 months. Reference standard was surgical pathology or 1-year minimum clinical follow-up. False-positive and false-negative examinations were reviewed to determine reasons for errors. Ninety-five bladder cancers were detected. CT urography accuracy: was 91.5% (650/710), sensitivity 86.3% (82/95), specificity 92.4% (568/615), positive predictive value 63.6% (82/129), and negative predictive value was 97.8% (568/581). Of 43 false positives, the majority of interpretation errors were due to benign prostatic hyperplasia (n = 12), trabeculated bladder (n = 9), and treatment changes (n = 8). Other causes include blood clots, mistaken normal anatomy, infectious/inflammatory changes, or had no cystoscopic correlate. Of 13 false negatives, 11 were due to technique, one to a large urinary residual, one to artifact. There were no errors in perception. CT urography is an accurate test for diagnosing bladder cancer; however, in protocols relying predominantly on excretory phase images, overall sensitivity remains insufficient to obviate cystoscopy. Awareness of bladder cancer mimics may reduce false-positive results. Improvements in CTU technique may reduce false-negative results.

Methods for threshold determination in multiplexed assays

DOEpatents

Tammero, Lance F. Bentley; Dzenitis, John M; Hindson, Benjamin J

2014-06-24

Methods for determination of threshold values of signatures comprised in an assay are described. Each signature enables detection of a target. The methods determine a probability density function of negative samples and a corresponding false positive rate curve. A false positive criterion is established and a threshold for that signature is determined as a point at which the false positive rate curve intersects the false positive criterion. A method for quantitative analysis and interpretation of assay results together with a method for determination of a desired limit of detection of a signature in an assay are also described.

Canine serum thyroglobulin autoantibodies in health, hypothyroidism and non-thyroidal illness.

PubMed

Dixon, R M; Mooney, C T

1999-06-01

Thyroglobulin autoantibody (TGAA) was measured in serum from dogs with hypothyroidism (n = 42), non-thyroidal illness (NTI) (n = 77) and clinically healthy dogs (n = 70) using a commercially available enzyme immunoassay kit. Precision studies were consistent with good intra-assay and inter-assay repeatability. TGAA positive results occurred in 15 of the 42 (36 per cent) hypothyroid and four healthy dogs of the remaining 147 animals resulting in a lower incidence of false positive results than obtained with previous TGAA assays. The presence of TGAA was not influenced by age, sex, neutering or pedigree status. Of the four apparently healthy TGAA -positive dogs, two had additional clinicopathological evidence of hypothyroidism. TGAA was positive in 43 per cent of hypothyroid dogs with unexpectedly normal serum c TSH concentrations and was particularly useful in the classification of these cases. Copyright 1999 W.B. Saunders Company Ltd.

Shear-wave elastography in the diagnosis of solid breast masses: what leads to false-negative or false-positive results?

PubMed

Yoon, Jung Hyun; Jung, Hae Kyoung; Lee, Jong Tae; Ko, Kyung Hee

2013-09-01

To investigate the factors that have an effect on false-positive or false-negative shear-wave elastography (SWE) results in solid breast masses. From June to December 2012, 222 breast lesions of 199 consecutive women (mean age: 45.3 ± 10.1 years; range, 21 to 88 years) who had been scheduled for biopsy or surgical excision were included. Greyscale ultrasound and SWE were performed in all women before biopsy. Final ultrasound assessments and SWE parameters (pattern classification and maximum elasticity) were recorded and compared with histopathology results. Patient and lesion factors in the 'true' and 'false' groups were compared. Of the 222 masses, 175 (78.8 %) were benign, and 47 (21.2 %) were malignant. False-positive rates of benign masses were significantly higher than false-negative rates of malignancy in SWE patterns, 36.6 % to 6.4 % (P < 0.001). Among both benign and malignant masses, factors showing significance among false SWE features were lesion size, breast thickness and lesion depth (all P < 0.05). All 47 malignant breast masses had SWE images of good quality. False SWE features were more significantly seen in benign masses. Lesion size, breast thickness and lesion depth have significance in producing false results, and this needs consideration in SWE image acquisition. • Shear-wave elastography (SWE) is widely used during breast imaging • At SWE, false-positive rates were significantly higher than false-negative rates • Larger size, breast thickness, depth and fair quality influences false-positive SWE features • Smaller size, larger breast thickness and depth influences false-negative SWE features.

Limitations of three-dimensional power Doppler angiography in preoperative evaluation of ovarian tumors.

PubMed

Silvestre, Liliane; Martins, Wellington P; Candido-Dos-Reis, Francisco J

2015-07-29

This study describes the accuracy of three-dimensional power Doppler (3D-PD) angiography as secondary method for differential diagnosis of ovarian tumors. Seventy-five women scheduled for surgical removal of adnexal masses were assessed by transvaginal ultrasound. Ovarian tumors were classified by IOTA simple rules and two three-dimensional blocks were recorded. In a second step analyses, a 4 cm(3) spherical sample was obtained from the highest vascularized solid area of each stored block. Vascularization index (VI), flow index (FI) and vascularization-flow index (VFI) were calculated. The repeatability was assessed by concordance correlation coefficient (CCC) and limits of agreement (LoA), and diagnostic accuracy by area under ROC curve. IOTA simple rules classified 26 cases as benign, nine as inconclusive and 40 as malignant. There were eight false positive and no false negative. Among the masses classified as inconclusive or malignant by IOTA simple rules, the CCCs were 0.91 for VI, 0.70 for FI, and 0.86 for VFI. The areas under ROC curve were 0.82 for VI, 0.67 for FI and 0.81 for VFI. 3D-PD angiography presented considerable intraobserver variability and low accuracy for identifying false positive results of IOTA simple rules.

False negative pericardial Focused Assessment with Sonography for Trauma examination following cardiac rupture from blunt thoracic trauma: a case report.

PubMed

Baker, Laura; Almadani, Ammar; Ball, Chad G

2015-07-15

The Focused Assessment with Sonography for Trauma examination is an invaluable tool in the initial assessment of any injured patient. Although highly sensitive and accurate for identifying hemoperitoneum, occasional false negative results do occur in select scenarios. We present a previously unreported case of survival following blunt cardiac rupture with associated negative pericardial window due to a concurrent pericardial wall laceration. A healthy 46-year-old white woman presented to our level 1 trauma center with hemodynamic instability following a motor vehicle collision. Although her abdominal Focused Assessment with Sonography for Trauma windows were positive for fluid, her pericardial window was negative. After immediate transfer to the operating room in the setting of persistent instability, a subsequent thoracotomy identified a blunt cardiac rupture that was draining into the ipsilateral pleural space via an adjacent tear in the pericardium. The cardiac injury was controlled with digital pressure, resuscitation completed, and then repaired using standard cardiorrhaphy techniques. Following repair of her injuries (left ventricle, left atrial appendage, and liver), her postoperative course was uneventful. Evaluation of the pericardial space using Focused Assessment with Sonography for Trauma is an important component in the initial assessment of the severely injured patient. Even in cases of blunt mechanisms however, clinicians must be wary of occasional false negative pericardial ultrasound evaluations secondary to a concomitant pericardial laceration and subsequent decompression of hemorrhage from the cardiac rupture into the ipsilateral pleural space.

Accuracy of lung cancer ICD-9-CM codes in Umbria, Napoli 3 Sud and Friuli Venezia Giulia administrative healthcare databases: a diagnostic accuracy study

PubMed Central

Montedori, Alessandro; Bidoli, Ettore; Serraino, Diego; Fusco, Mario; Giovannini, Gianni; Casucci, Paola; Franchini, David; Granata, Annalisa; Ciullo, Valerio; Vitale, Maria Francesca; Gobbato, Michele; Chiari, Rita; Cozzolino, Francesco; Orso, Massimiliano; Orlandi, Walter

2018-01-01

Objectives To assess the accuracy of International Classification of Diseases 9th Revision–Clinical Modification (ICD-9-CM) codes in identifying subjects with lung cancer. Design A cross-sectional diagnostic accuracy study comparing ICD-9-CM 162.x code (index test) in primary position with medical chart (reference standard). Case ascertainment was based on the presence of a primary nodular lesion in the lung and cytological or histological documentation of cancer from a primary or metastatic site. Setting Three operative units: administrative databases from Umbria Region (890 000 residents), ASL Napoli 3 Sud (NA) (1 170 000 residents) and Friuli Venezia Giulia (FVG) Region (1 227 000 residents). Participants Incident subjects with lung cancer (n=386) diagnosed in primary position between 2012 and 2014 and a population of non-cases (n=280). Outcome measures Sensitivity, specificity and positive predictive value (PPV) for 162.x code. Results 130 cases and 94 non-cases were randomly selected from each database and the corresponding medical charts were reviewed. Most of the diagnoses for lung cancer were performed in medical departments. True positive rates were high for all the three units. Sensitivity was 99% (95% CI 95% to 100%) for Umbria, 97% (95% CI 91% to 100%) for NA, and 99% (95% CI 95% to 100%) for FVG. The false positive rates were 24%, 37% and 23% for Umbria, NA and FVG, respectively. PPVs were 79% (73% to 83%)%) for Umbria, 58% (53% to 63%)%) for NA and 79% (73% to 84%)%) for FVG. Conclusions Case ascertainment for lung cancer based on imaging or endoscopy associated with histological examination yielded an excellent sensitivity in all the three administrative databases. PPV was moderate for Umbria and FVG but lower for NA. PMID:29773701

Solid pulmonary nodule risk assessment and decision analysis: comparison of four prediction models in 285 cases.

PubMed

Perandini, Simone; Soardi, Gian Alberto; Motton, Massimiliano; Rossi, Arianna; Signorini, Manuel; Montemezzi, Stefania

2016-09-01

The aim of this study was to compare classification results from four major risk prediction models in a wide population of incidentally detected solitary pulmonary nodules (SPNs) which were selected to crossmatch inclusion criteria for the selected models. A total of 285 solitary pulmonary nodules with a definitive diagnosis were evaluated by means of four major risk assessment models developed from non-screening populations, namely the Mayo, Gurney, PKUPH and BIMC models. Accuracy was evaluated by receiver operating characteristic (ROC) area under the curve (AUC) analysis. Each model's fitness to provide reliable help in decision analysis was primarily assessed by adopting a surgical threshold of 65 % and an observation threshold of 5 % as suggested by ACCP guidelines. ROC AUC values, false positives, false negatives and indeterminate nodules were respectively 0.775, 3, 8, 227 (Mayo); 0.794, 41, 6, 125 (Gurney); 0.889, 42, 0, 144 (PKUPH); 0.898, 16, 0, 118 (BIMC). Resultant data suggests that the BIMC model may be of greater help than Mayo, Gurney and PKUPH models in preoperative SPN characterization when using ACCP risk thresholds because of overall better accuracy and smaller numbers of indeterminate nodules and false positive results. • The BIMC and PKUPH models offer better characterization than older prediction models • Both the PKUPH and BIMC models completely avoided false negative results • The Mayo model suffers from a large number of indeterminate results.

Effects of depressive disorder on false memory for emotional information.

PubMed

Yeh, Zai-Ting; Hua, Mau-Sun

2009-01-01

This study explored with a false memory paradigm whether (1) depressed patients revealed more false memories and (2) whether more negative false than positive false recognition existed in subjects with depressive disorders. Thirty-two patients suffering from a major depressive episode (DSM-IV criteria), and 30 age- and education-matched normal control subjects participated in this study. After the presentation of a list of positive, negative, and neutral association items in the learning phase, subjects were asked to give a yes/no response in the recognition phase. They were also asked to rate 81 recognition items with emotional valence scores. The results revealed more negative false memories in the clinical depression group than in the normal control group; however, we did not find more negative false memories than positive ones in patients. When compared with the normal group, a more conservative response criterion for positive items was evident in patient groups. It was also found that when compared with the normal group, the subjects in the depression group perceived the positive items as less positive. On the basis of present results, it is suggested that depressed subjects judged the emotional information with criteria different from normal individuals, and patients' emotional memory intensity is attenuated by their mood.

Commercial radioimmunoassay for beta subunit of human chorionic gonadotropin: falsely positive determinations due to elevated serum luteinizing hormone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fowler, J.E. Jr.; Platoff, G.E.; Kubrock, C.A.

1982-01-01

Among 17 men who had received seemingly curative treatment for unilateral non-seminomatous germ cell tumors for the testis and who had consistently normal serum human chorionic gonadotropin (HCG) levels at a reference laboratory, 7 (41%) had at least one falsely positive commercial serum HCG determination. To investigate the cause of these falsely positive determinations the authors measured the cross reactivity of luteinizing hormone (LH) and follicle stimulating hormone (FSH) standards in the commercial HCG assay, and studied the relationships between commercial HCG levels and serum LH levels, serum FSH levels and gonadal status in men with and without normal gonadalmore » function. The falsely positive HCG determinations appeared to be due to elevated serum LH levels and cross reactivity of LH in the commercial HCG assay because: 1) there was substantial cross reactivity of the LH standards in the commercial assay, 2) the serum LH was elevated in four of six men with solitary testes, 3) there was a striking correlation between elevated serum LH levels and falsely elevated commercial HCG levels in ten men with solitary or absent testes, and 4) there were no falsely positive HCG determinations in 13 normal men but there were falsely positive HCG determinations in seven of ten anorchid men.« less

[Perforation of hollow organs in the abdominal contusion: diagnostic features and prognostic factors of death].

PubMed

Nicolau, A E; Merlan, V; Dinescu, G; Crăciun, M; Kitkani, A; Beuran, M

2012-01-01

Blunt hollow viscus perforations (HVP) due to abdominal contusions (AC), although rare, are difficult to diagnose early and are associated with a high mortality. Our paper analyses retrospectively data from patients operated for HVP between January 2005 and January 2009, the efficiency of different diagnostic tools, mortality and prognostic factors for death. There were 62 patients operated for HVP, 14 of which had isolated abdominal contusion and 48 were poly trauma patients. There were 9 women and 53 men, the mean age was 41.5 years (SD: +17,9), the mean ISS was 32.94 (SD: +15,94), 23 patients had associated solid viscus injuries (SVI). Clinical examination was irelevant for 16 of the 62 patients, abdominal Xray was false negative for 30 out of 35 patients and abdominal ultrasound was false negative for 16 out of 60 patients. Abdominal CT was initially false negative for 7 out of 38 patients: for 4 of them the abdominal CT was repeated and was positive for HVP, for 3 patients a diagnostic laparoscopy was performed. Direct signs for HVP on abdominal CT were present for 3 out of 38 patients. Diagnostic laparoscopy was performed for 7 patients with suspicion for HVP, and was positive for 6 of them and false negative for a patient with a duodenal perforation. Single organ perforations were present in 55 cases, multi organ perforations were present in 7 cases. There were 15 deaths (15.2%), most of them caused by haemodynamic instability (3 out of 6 patients) and associated lesions: SOL for 9 out of 23 cases, pelvic fracture (PF) for 6 out of 14 patients, craniocerebral trauma (CCT) for 12 out of 33 patients.Multivariate analysis showed that the prognostic factors for death were ISS value (p = 0,023) and associated CCT (odds ratio = 4,95; p = 0,017). The following factors were not confirmed as prognostic factors for death: age, haemodynamic instability, associated SVI, thoracic trauma (TT), pelvic fractures (PF), limbs fractures (LF) and admission-operation interval under 6 hours. Hollow viscus perforations due to abdominal contusions have a high mortality, early diagnosis is difficult, repeated abdominal CT and the selective use of diagnostic laparoscopy for haemodynamic stable patients with ambiguous clinical examination and diagnostic imaging are salutary. Prognostic factors for death were the ISS value and associated craniocerebral trauma.

Fluoroscopy-Guided Sacroiliac Joint Injection: Description of a Modified Technique.

PubMed

Kasliwal, Prasad Jaychand; Kasliwal, Sapana

2016-02-01

Sacroiliac joint (SIJ) pathology is a common etiologic cause for 10 - 27% of cases of mechanical low back pain (LBP) below the L5 level. In the absence of definite clinical or radiologic diagnostic criteria, controlled blocks of the SIJ have become the choice assessment method for making the diagnosis of SIJ pain. The SI joint is most often characterized as a large, auricular-shaped, diarthrodial synovial joint. In reality, its synovial characteristic is limited only to the distal third and anterior third. In SIJ interventions, the lateral view has been underutilized. In our technique, we used the lateral view to create a three-dimensional view of the SIJ to aid in gauging the accurateness of the contrast spread and to obtain a precise block. After obtaining appropriate fluoroscopic images, a curved tip spinal needle was directed into the inferior aspect of the SIJ using a posterior approach. As the needle contacts firm tissues on the posterior aspect of the joint, position of the needle tip is checked using lateral fluoroscopy. In the lateral view, the needle tip position is manipulated to keep it in the anterior third of the SIJ and contrast is injected. Our criteria for accurate SIJ block, in posteroanterior (PA) view, is the injection of the contrast medium should outline the joint space and the contrast medium should be seen to travel cephalad along the joint line. In the lateral view, the contrast medium most densely outlines the parameter of the joint. We have utilized this method with good effect in approximately 30 cases over one year. Out of 30 cases, needle position and contrast spread was satisfactory in 28 and 27 cases, respectively. So satisfactory needle placement and contrast spread was in 93% and 87% cases. Pain relief of 80% or more after intra-articular injection of local anesthetic was seen in 50% (15 of 30) patients; pain relief of 50 - 79% was witnessed in 30% (9 of 30) patients. Thus, pain decreased 50% or more in 80% (24 of 30) of the joints. Out of 24 joints where we got satisfactory needle position and contrast spread, 23 joints got more than 50% relief. Thus, if needle position and contrast spread is satisfactory as per the criteria, pain relief of 50% or more was in 96% (23 of 24) of joints. There are few possible limitations with this study like difficulty to go up to the anterior third of the SIJ, it may be more painful as a narrow joint line has to be travelled in depth, sciatic numbness due to drug leak, or injuring the pelvic structure. Advantages of this method are that depth and level of the needle tip for a SIJ block is described for the more precise block. This will reduce false positive and false negative results, i.e., sensitivity and specificity of SIJ blocks and results for diagnostic blocks become more reliable. It will also reduce the chances of a case getting abandoned due to inappropriate contrast spread obscuring the fluoroscopic landmarks. As we know the depth of the needle, the chances of injuring pelvic structures become less and safety improves.

Non-invasive prenatal testing for fetal chromosomal abnormalities by low-coverage whole-genome sequencing of maternal plasma DNA: review of 1982 consecutive cases in a single center.

PubMed

Lau, T K; Cheung, S W; Lo, P S S; Pursley, A N; Chan, M K; Jiang, F; Zhang, H; Wang, W; Jong, L F J; Yuen, O K C; Chan, H Y C; Chan, W S K; Choy, K W

2014-03-01

To review the performance of non-invasive prenatal testing (NIPT) by low-coverage whole-genome sequencing of maternal plasma DNA at a single center. The NIPT result and pregnancy outcome of 1982 consecutive cases were reviewed. NIPT was based on low coverage (0.1×) whole-genome sequencing of maternal plasma DNA. All subjects were contacted for pregnancy and fetal outcome. Of the 1982 NIPT tests, a repeat blood sample was required in 23 (1.16%). In one case, a conclusive report could not be issued, probably because of an abnormal vanished twin fetus. NIPT was positive for common trisomies in 29 cases (23 were trisomy 21, four were trisomy 18 and two were trisomy 13); all were confirmed by prenatal karyotyping (specificity=100%). In addition, 11 cases were positive for sex-chromosomal abnormalities (SCA), and nine cases were positive for other aneuploidies or deletion/duplication. Fourteen of these 20 subjects agreed to undergo further investigations, and the abnormality was found to be of fetal origin in seven, confined placental mosaicism (CPM) in four, of maternal origin in two and not confirmed in one. Overall, 85.7% of the NIPT-suspected SCA were of fetal origin, and 66.7% of the other abnormalities were caused by CPM. Two of the six cases suspected or confirmed to have CPM were complicated by early-onset growth restriction requiring delivery before 34 weeks. Fetal outcome of the NIPT-negative cases was ascertained in 1645 (85.15%). Three chromosomal abnormalities were not detected by NIPT, including one case each of a balanced translocation, unbalanced translocation and triploidy. There were no known false negatives involving the common trisomies (sensitivity=100%). Low-coverage whole-genome sequencing of maternal plasma DNA was highly accurate in detecting common trisomies. It also enabled the detection of other aneuploidies and structural chromosomal abnormalities with high positive predictive value. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.

Measuring implicit attitudes: A positive framing bias flaw in the Implicit Relational Assessment Procedure (IRAP).

PubMed

O'Shea, Brian; Watson, Derrick G; Brown, Gordon D A

2016-02-01

How can implicit attitudes best be measured? The Implicit Relational Assessment Procedure (IRAP), unlike the Implicit Association Test (IAT), claims to measure absolute, not just relative, implicit attitudes. In the IRAP, participants make congruent (Fat Person-Active: false; Fat Person-Unhealthy: true) or incongruent (Fat Person-Active: true; Fat Person-Unhealthy: false) responses in different blocks of trials. IRAP experiments have reported positive or neutral implicit attitudes (e.g., neutral attitudes toward fat people) in cases in which negative attitudes are normally found on explicit or other implicit measures. It was hypothesized that these results might reflect a positive framing bias (PFB) that occurs when participants complete the IRAP. Implicit attitudes toward categories with varying prior associations (nonwords, social systems, flowers and insects, thin and fat people) were measured. Three conditions (standard, positive framing, and negative framing) were used to measure whether framing influenced estimates of implicit attitudes. It was found that IRAP scores were influenced by how the task was framed to the participants, that the framing effect was modulated by the strength of prior stimulus associations, and that a default PFB led to an overestimation of positive implicit attitudes when measured by the IRAP. Overall, the findings question the validity of the IRAP as a tool for the measurement of absolute implicit attitudes. A new tool (Simple Implicit Procedure:SIP) for measuring absolute, not just relative, implicit attitudes is proposed. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

The efficacy and cost of alternative strategies for systematic screening for type 2 diabetes in the U.S. population 45-74 years of age.

PubMed

Johnson, Susan L; Tabaei, Bahman P; Herman, William H

2005-02-01

To simulate the outcomes of alternative strategies for screening the U.S. population 45-74 years of age for type 2 diabetes. We simulated screening with random plasma glucose (RPG) and cut points of 100, 130, and 160 mg/dl and a multivariate equation including RPG and other variables. Over 15 years, we simulated screening at intervals of 1, 3, and 5 years. All positive screening tests were followed by a diagnostic fasting plasma glucose or an oral glucose tolerance test. Outcomes include the numbers of false-negative, true-positive, and false-positive screening tests and the direct and indirect costs. At year 15, screening every 3 years with an RPG cut point of 100 mg/dl left 0.2 million false negatives, an RPG of 130 mg/dl or the equation left 1.3 million false negatives, and an RPG of 160 mg/dl left 2.8 million false negatives. Over 15 years, the absolute difference between the most sensitive and most specific screening strategy was 4.5 million true positives and 476 million false-positives. Strategies using RPG cut points of 130 mg/dl or the multivariate equation every 3 years identified 17.3 million true positives; however, the equation identified fewer false-positives. The total cost of the most sensitive screening strategy was $42.7 billion and that of the most specific strategy was $6.9 billion. Screening for type 2 diabetes every 3 years with an RPG cut point of 130 mg/dl or the multivariate equation provides good yield and minimizes false-positive screening tests and costs.

Breast cancer detection risk in screening mammography after a false-positive result.

PubMed

Castells, X; Román, M; Romero, A; Blanch, J; Zubizarreta, R; Ascunce, N; Salas, D; Burón, A; Sala, M

2013-02-01

False-positives are a major concern in breast cancer screening. However, false-positives have been little evaluated as a prognostic factor for cancer detection. Our aim was to evaluate the association of false-positive results with the cancer detection risk in subsequent screening participations over a 17-year period. This is a retrospective cohort study of 762,506 women aged 45-69 years, with at least two screening participations, who underwent 2,594,146 screening mammograms from 1990 to 2006. Multilevel discrete-time hazard models were used to estimate the adjusted odds ratios (OR) of breast cancer detection in subsequent screening participations in women with false-positive results. False-positives involving a fine-needle aspiration cytology or a biopsy had a higher cancer detection risk than those involving additional imaging procedures alone (OR = 2.69; 95%CI: 2.28-3.16 and OR = 1.81; 95%CI: 1.70-1.94, respectively). The risk of cancer detection increased substantially if women with cytology or biopsy had a familial history of breast cancer (OR = 4.64; 95%CI: 3.23-6.66). Other factors associated with an increased cancer detection risk were age 65-69 years (OR = 1.84; 95%CI: 1.67-2.03), non-attendance at the previous screening invitation (OR = 1.26; 95%CI: 1.11-1.43), and having undergone a previous benign biopsy outside the screening program (OR = 1.24; 95%CI: 1.13-1.35). Women with a false-positive test have an increased risk of cancer detection in subsequent screening participations, especially those with a false-positive result involving cytology or biopsy. Understanding the factors behind this association could provide valuable information to increase the effectiveness of breast cancer screening. Copyright © 2012 Elsevier Ltd. All rights reserved.

Psychological distress in U.S. women who have experienced false-positive mammograms.

PubMed

Jatoi, Ismail; Zhu, Kangmin; Shah, Mona; Lawrence, William

2006-11-01

In the United States, approximately 10.7% of all screening mammograms lead to a false-positive result, but the overall impact of false-positives on psychological well-being is poorly understood. Data were analyzed from the 2000 U.S. National Health Interview Survey (NHIS), the most recent national survey that included a cancer control module. Study subjects were 9,755 women who ever had a mammogram, of which 1,450 had experienced a false-positive result. Psychological distress was assessed using the validated K6 questionnaire and logistic regression was used to discern any association with previous false-positive mammograms. In a multivariate analysis, women who had indicated a previous false-positive mammogram were more likely to report feeling sad (OR = 1.18, 95% CI, 1.03-1.35), restless (OR = 1.23, 95% CI, 1.08-1.40), worthless (OR = 1.27, 95% CI, 1.04-1.54), and finding that everything was an effort (OR = 1.27, 95% CI, 1.10-1.47). These women were also more likely to have seen a mental health professional in the 12 months preceding the survey (OR = 1.28, 95% CI, 1.03-1.58) and had a higher composite score on all items of the K6 scale (P < 0.0001), a reflection of increased psychological distress. Analyses by age and race revealed that, among women who had experienced false-positives, younger women were more likely to feel that everything was an effort, and blacks were more likely to feel restless. In a random sampling of the U.S. population, women who had previously experienced false-positive mammograms were more likely to report symptoms of anxiety and depression.

False Positive Probabilities for all Kepler Objects of Interest: 1284 Newly Validated Planets and 428 Likely False Positives

NASA Astrophysics Data System (ADS)

Morton, Timothy D.; Bryson, Stephen T.; Coughlin, Jeffrey L.; Rowe, Jason F.; Ravichandran, Ganesh; Petigura, Erik A.; Haas, Michael R.; Batalha, Natalie M.

2016-05-01

We present astrophysical false positive probability calculations for every Kepler Object of Interest (KOI)—the first large-scale demonstration of a fully automated transiting planet validation procedure. Out of 7056 KOIs, we determine that 1935 have probabilities <1% of being astrophysical false positives, and thus may be considered validated planets. Of these, 1284 have not yet been validated or confirmed by other methods. In addition, we identify 428 KOIs that are likely to be false positives, but have not yet been identified as such, though some of these may be a result of unidentified transit timing variations. A side product of these calculations is full stellar property posterior samplings for every host star, modeled as single, binary, and triple systems. These calculations use vespa, a publicly available Python package that is able to be easily applied to any transiting exoplanet candidate.

Lupus erythematosus cell preparation, antinuclear factor and antideoxyribonucleic acid antibody incongruity in systemic lupus erythematosus.

PubMed

Chee, Y C

1983-01-01

'Total antinuclear antibody' (ANF) is detected by the fluorescent antinuclear antibody technique which is a screening test, positive in 99% of systemic lupus erythematosus (SLE) sera. The LE factor (positive in 75% of SLE sera), like the anti-DNA antibody, is an antinuclear antibody but directed against DNA-histone. ANF-negative SLE is a clinical entity with absence of these antibodies. A false negative ANF, in the presence of high titre anti-DNA antibody and/or LE cells, is illustrated in two cases of SLE. Postulated mechanisms for this phenomenon are interference in ANF detection by rheumatoid factor, and the prozone effect on the immunofluorescent tests.

How to limit false positives in environmental DNA and metabarcoding?

PubMed

Ficetola, Gentile Francesco; Taberlet, Pierre; Coissac, Eric

2016-05-01

Environmental DNA (eDNA) and metabarcoding are boosting our ability to acquire data on species distribution in a variety of ecosystems. Nevertheless, as most of sampling approaches, eDNA is not perfect. It can fail to detect species that are actually present, and even false positives are possible: a species may be apparently detected in areas where it is actually absent. Controlling false positives remains a main challenge for eDNA analyses: in this issue of Molecular Ecology Resources, Lahoz-Monfort et al. () test the performance of multiple statistical modelling approaches to estimate the rate of detection and false positives from eDNA data. Here, we discuss the importance of controlling for false detection from early steps of eDNA analyses (laboratory, bioinformatics), to improve the quality of results and allow an efficient use of the site occupancy-detection modelling (SODM) framework for limiting false presences in eDNA analysis. © 2016 John Wiley & Sons Ltd.

[Benefit of clinical and laboratory parameters for the diagnosis of endometritis in dairy cows].

PubMed

Hässig, M; Steinmann, B; Wittenbrink, M M

2010-09-01

The goal of this work was to answer the question of whether or not there are significant differences between cows with abnormal vaginal discharge and cows with the diagnosis of puerperal or chronic endometritis, using blood and urine parameters. In addition, cows with and without vaginal discharge were examined for significant bacteriological differences in uterine mucous samples. The question of false positive and false negatives from the diagnosis of endometritis was also investigated. A total of 35 matched-pairs (+/-vaginal discharge) from 27 stables was examined 21 to 63 days post partum. The examination consisted of a rectal and vaginal exam, urine and blood samples as well as vaginal swab from the corpus uteri using a Folmer-Nielsen-Catheter. Based on the history vaginal discharge occurred more frequently in dystocia and retentio secundinarium. Cows with a history of distocia and retentio secundinarium showed significantly more vaginal discharge. Gammaglutamyltransferase (GGT; p=0.01) and cholesterine (p=0.04) were different in cows with endometritis. The bacteriology results showed a statistically significant difference (p<0.01) only for Escherichia coli and Arcanobacterium pyogenes. The Folmer-Nielsen smears/endometritis showed a significant difference between the two groups (p<0.01). In a multivariate analysis with final step-back procedure regarding endometritis Gammaglutamyltransferase (GGT) and Betahydroxybutteracid (BHB) were significant different (p=0.02). The hypothesis vaginal discharge alike endometritis showed that 34 % of the clinical suspicious cases were recorded as false negatives. In the non-suspicious cases 20 % were diagnosed as false negative.

Consensus review of discordant findings maximizes cancer detection rate in double-reader screening mammography: Irish National Breast Screening Program experience.

PubMed

Shaw, Colette M; Flanagan, Fidema L; Fenlon, Helen M; McNicholas, Michelle M

2009-02-01

To assesses consensus review of discordant screening mammography findings in terms of its sensitivity, safety, and effect on overall performance in the first 6 years of operation of the Irish National Breast Screening Program (NBSP). Women who participated in the Irish NBSP gave written informed consent for use of their data for auditing purposes. Local ethics committee approval was obtained. The study population consisted of women who participated in the Irish NBSP and underwent initial screening mammography at one of the two screening centers serving the eastern part of Ireland between 2000 and 2005. Independent double reading of mammograms was performed. When the readers disagreed regarding referral, the case was reviewed by a consensus panel. Of the 128 569 screenings performed, 1335 (1%) were discussed by consensus. Of the 1335 cases discussed by consensus, 606 (45.39%) were recalled for further assessment. This resulted in an overall recall rate of 4.41%. In those recalled to assessment, 71 cases of malignant disease were diagnosed (ductal carcinoma in situ, n = 24; invasive cancer, n = 47). The remaining 729 patients were returned to biennial screening. Of these 729 patients, seven had false-negative findings that were identified in the subsequent screening round. Use of the highest reader recall method, in which a patient is recalled if her findings are deemed abnormal by either reader, could potentially increase the cancer detection rate by 0.6 per 1000 women screened but would increase the recall rate by 12.69% and the number of false-positive findings by 15.37%. The consensus panel identified 71 (7.33%) of 968 cancers diagnosed. Consensus review substantially reduced the number of cases recalled and was associated with a low false-negative rate.

An ontology-driven, case-based clinical decision support model for removable partial denture design

NASA Astrophysics Data System (ADS)

Chen, Qingxiao; Wu, Ji; Li, Shusen; Lyu, Peijun; Wang, Yong; Li, Miao

2016-06-01

We present the initial work toward developing a clinical decision support model for specific design of removable partial dentures (RPDs) in dentistry. We developed an ontological paradigm to represent knowledge of a patient’s oral conditions and denture component parts. During the case-based reasoning process, a cosine similarity algorithm was applied to calculate similarity values between input patients and standard ontology cases. A group of designs from the most similar cases were output as the final results. To evaluate this model, the output designs of RPDs for 104 randomly selected patients were compared with those selected by professionals. An area under the curve of the receiver operating characteristic (AUC-ROC) was created by plotting true-positive rates against the false-positive rate at various threshold settings. The precision at position 5 of the retrieved cases was 0.67 and at the top of the curve it was 0.96, both of which are very high. The mean average of precision (MAP) was 0.61 and the normalized discounted cumulative gain (NDCG) was 0.74 both of which confirmed the efficient performance of our model. All the metrics demonstrated the efficiency of our model. This methodology merits further research development to match clinical applications for designing RPDs. This paper is organized as follows. After the introduction and description of the basis for the paper, the evaluation and results are presented in Section 2. Section 3 provides a discussion of the methodology and results. Section 4 describes the details of the ontology, similarity algorithm, and application.

An ontology-driven, case-based clinical decision support model for removable partial denture design.

PubMed

Chen, Qingxiao; Wu, Ji; Li, Shusen; Lyu, Peijun; Wang, Yong; Li, Miao

2016-06-14

We present the initial work toward developing a clinical decision support model for specific design of removable partial dentures (RPDs) in dentistry. We developed an ontological paradigm to represent knowledge of a patient's oral conditions and denture component parts. During the case-based reasoning process, a cosine similarity algorithm was applied to calculate similarity values between input patients and standard ontology cases. A group of designs from the most similar cases were output as the final results. To evaluate this model, the output designs of RPDs for 104 randomly selected patients were compared with those selected by professionals. An area under the curve of the receiver operating characteristic (AUC-ROC) was created by plotting true-positive rates against the false-positive rate at various threshold settings. The precision at position 5 of the retrieved cases was 0.67 and at the top of the curve it was 0.96, both of which are very high. The mean average of precision (MAP) was 0.61 and the normalized discounted cumulative gain (NDCG) was 0.74 both of which confirmed the efficient performance of our model. All the metrics demonstrated the efficiency of our model. This methodology merits further research development to match clinical applications for designing RPDs. This paper is organized as follows. After the introduction and description of the basis for the paper, the evaluation and results are presented in Section 2. Section 3 provides a discussion of the methodology and results. Section 4 describes the details of the ontology, similarity algorithm, and application.

Evaluation of MTANNs for eliminating false-positive with different computer aided pulmonary nodules detection software.

PubMed

Shi, Zhenghao; Ma, Jiejue; Feng, Yaning; He, Lifeng; Suzuki, Kenji

2015-11-01

MTANN (Massive Training Artificial Neural Network) is a promising tool, which applied to eliminate false-positive for thoracic CT in recent years. In order to evaluate whether this method is feasible to eliminate false-positive of different CAD schemes, especially, when it is applied to commercial CAD software, this paper evaluate the performance of the method for eliminating false-positives produced by three different versions of commercial CAD software for lung nodules detection in chest radiographs. Experimental results demonstrate that the approach is useful in reducing FPs for different computer aided lung nodules detection software in chest radiographs.

[Value of the cytologic diagnosis of adenopathies by aspiration biopsy. Cytohistologic comparison of 1756 cases].

PubMed

Zajdela, A; Ennuyer, A; Bataini, P; Poncet, P

1976-01-01

The value of the cytologic diagnosis by aspiration needle biopsy is analysed in a series of 1756 adenopathies, verified by histological examination (1311 malignant nodes and 445 inflammatory or normal lymph nodes). The result is that a large number of lymph node tumours, either primary or secondary, are identified by the cytologic examination (from 77% to 91% of the cases according to the explored zone). Furthermore the virtually non existent percentage of false positive results (3% of the cases) proves the great accuracy of this method in the diagnosis of malignancy. In contrast, the diagnosis of benign nature must never be stated without biopsy (2% to 4% of the cases are erroneous by negative according to the explored zone). Indeed, even if benign cells are obtained, nothing allows to eliminate a malignant tumour or a limited inflammatory zone, not reached by the needle.

Computerized mass detection in whole breast ultrasound images: reduction of false positives using bilateral subtraction technique

NASA Astrophysics Data System (ADS)

Ikedo, Yuji; Fukuoka, Daisuke; Hara, Takeshi; Fujita, Hiroshi; Takada, Etsuo; Endo, Tokiko; Morita, Takako

2007-03-01

The comparison of left and right mammograms is a common technique used by radiologists for the detection and diagnosis of masses. In mammography, computer-aided detection (CAD) schemes using bilateral subtraction technique have been reported. However, in breast ultrasonography, there are no reports on CAD schemes using comparison of left and right breasts. In this study, we propose a scheme of false positive reduction based on bilateral subtraction technique in whole breast ultrasound images. Mass candidate regions are detected by using the information of edge directions. Bilateral breast images are registered with reference to the nipple positions and skin lines. A false positive region is detected based on a comparison of the average gray values of a mass candidate region and a region with the same position and same size as the candidate region in the contralateral breast. In evaluating the effectiveness of the false positive reduction method, three normal and three abnormal bilateral pairs of whole breast images were employed. These abnormal breasts included six masses larger than 5 mm in diameter. The sensitivity was 83% (5/6) with 13.8 (165/12) false positives per breast before applying the proposed reduction method. By applying the method, false positives were reduced to 4.5 (54/12) per breast without removing a true positive region. This preliminary study indicates that the bilateral subtraction technique is effective for improving the performance of a CAD scheme in whole breast ultrasound images.

Evaluation of fecal elastase and serum cholecystokinin in dogs with a false positive fecal elastase test.

PubMed

Steiner, J M; Rehfeld, J F; Pantchev, N

2010-01-01

An assay for the measurement of pancreatic elastase in dog feces has been introduced. The goal of this study was to evaluate the rate of false-positive fecal-elastase test results in dogs with suspected exocrine pancreatic insufficiency (EPI) and to assess serum cholecystokinin (CCK) concentrations in dogs with a false positive fecal elastase test result. Twenty-six fecal and serum samples from dogs suspected of EPI, for which samples had been submitted to a commercial laboratory (Vet Med Labor) for analysis. Prospective study. Serum trypsin-like immunoreactivity (TLI) was measured in 26 dogs with a decreased fecal elastase concentration of <10 microg/g feces. Serum CCK concentrations were measured in 21 of these dogs. Of 26 dogs with a decreased fecal elastase concentration, 6 (23%) had serum TLI concentrations within or above the reference range. Serum CCK concentrations were significantly higher in dogs with a true positive fecal elastase test result (median: 1.1 pmol/L; range: 0.1-3.3 pmol/L) than in those with a false positive fecal elastase test result (median: 0.1 pmol/L; range: 0.1-0.9 pmol/L; P value = .0163). The rate of false positive fecal elastase test results was high in this group of dogs, suggesting that diagnosis of EPI must be confirmed by other means. The decreased CCK concentration in dogs with a false positive fecal elastase test result could suggest that false positive results are because of decreased stimulation of exocrine pancreatic function caused by other conditions.

Code-based Diagnostic Algorithms for Idiopathic Pulmonary Fibrosis. Case Validation and Improvement.

PubMed

Ley, Brett; Urbania, Thomas; Husson, Gail; Vittinghoff, Eric; Brush, David R; Eisner, Mark D; Iribarren, Carlos; Collard, Harold R

2017-06-01

Population-based studies of idiopathic pulmonary fibrosis (IPF) in the United States have been limited by reliance on diagnostic code-based algorithms that lack clinical validation. To validate a well-accepted International Classification of Diseases, Ninth Revision, code-based algorithm for IPF using patient-level information and to develop a modified algorithm for IPF with enhanced predictive value. The traditional IPF algorithm was used to identify potential cases of IPF in the Kaiser Permanente Northern California adult population from 2000 to 2014. Incidence and prevalence were determined overall and by age, sex, and race/ethnicity. A validation subset of cases (n = 150) underwent expert medical record and chest computed tomography review. A modified IPF algorithm was then derived and validated to optimize positive predictive value. From 2000 to 2014, the traditional IPF algorithm identified 2,608 cases among 5,389,627 at-risk adults in the Kaiser Permanente Northern California population. Annual incidence was 6.8/100,000 person-years (95% confidence interval [CI], 6.1-7.7) and was higher in patients with older age, male sex, and white race. The positive predictive value of the IPF algorithm was only 42.2% (95% CI, 30.6 to 54.6%); sensitivity was 55.6% (95% CI, 21.2 to 86.3%). The corrected incidence was estimated at 5.6/100,000 person-years (95% CI, 2.6-10.3). A modified IPF algorithm had improved positive predictive value but reduced sensitivity compared with the traditional algorithm. A well-accepted International Classification of Diseases, Ninth Revision, code-based IPF algorithm performs poorly, falsely classifying many non-IPF cases as IPF and missing a substantial proportion of IPF cases. A modification of the IPF algorithm may be useful for future population-based studies of IPF.

Sonographic Elastography of Mastitis.

PubMed

Sousaris, Nicholas; Barr, Richard G

2016-08-01

Sonographic elastography has been shown to be a useful imaging modality in characterizing breast lesions as benign or malignant. However, in preliminary research, mastitis has given false-positive findings on both strain and shear wave elastography. In this article, we review the findings in mastitis with and without abscess formation on both strain and shear wave elastography. The elastographic findings in all cases were suggestive of a malignancy according to published thresholds. In cases of mastitis with abscess formation, there is a characteristic appearance, with a central very soft area (abscess cavity) and a very stiff outer rim (edema and inflammation). This appearance should raise the suspicion of mastitis with abscess formation, since these findings are rare in breast cancers.

Diagnosis of pyogenic pelvic inflammatory diseases by 99mTc-HMPAO leucocyte scintigraphy.

PubMed

Rachinsky, I; Boguslavsky, L; Goldstein, D; Golan, H; Pak, I; Katz, M; Lantsberg, S

2000-12-01

Pelvic inflammatory disease (PID) is one of the major health problems of women of child-bearing age. Among the most serious complications of PID is the formation of a tubo-ovarian abscess (TOA). Early diagnosis of this condition may prevent serious surgical complications such as peritonitis and sepsis, which may be fatal. The purpose of this study was to investigate the efficacy of technetium-99m hexamethylpropylene amine oxime (HMPAO) leucocyte scintigraphy in the diagnosis of TOA. Twenty women with high clinical suspicion of TOA underwent 99mTc-HMPAO leucocyte scintigraphy. The labelling of leucocytes with 99mTc-HMPAO was performed according to a standard protocol. Scans were obtained at 1, 3 and 24 h following the injection of the labelled leucocytes. In eight cases the early and/or late scan was positive, in 11 cases it was negative, and in one case of ovarian cyst torsion, confirmed by laparoscopy, it showed slight uptake in the capsule of the cyst (false-positive). The sensitivity of 99mTc-HMPAO leucocyte scintigraphy was 100%, specificity 91.6%, positive predictive value 89%, negative predictive value 100% and overall accuracy 95%. It is concluded that leucocyte scintigraphy is a non-invasive, safe, physiological and accurate procedure for the diagnosis of TOA. The 24-h scan is crucial, since in some cases the abscess was not clearly visualized on the early scan. Leucocyte scintigraphy may reduce the need for CT, diagnostic laparoscopy and unnecessary invasive surgical procedures.

Variation in false-positive rates of mammography reading among 1067 radiologists: a population-based assessment.

PubMed

Tan, Alai; Freeman, Daniel H; Goodwin, James S; Freeman, Jean L

2006-12-01

The accuracy of mammography reading varies among radiologists. We conducted a population-based assessment on radiologist variation in false- positive rates of screening mammography and its associated radiologist characteristics. About 27,394 screening mammograms interpreted by 1067 radiologists were identified from a 5% non-cancer sample of Medicare claims during 1998-1999. The data were linked to the American Medical Association Masterfile to obtain radiologist characteristics. Multilevel logistic regression models were used to examine the radiologist variation in false-positive rates of screening mammography and the associated radiologist characteristics. Radiologists varied substantially in the false-positive rates of screening mammography (ranging from 1.5 to 24.1%, adjusting for patient characteristics). A longer time period since graduation is associated with lower false-positive rates (odds ratio [OR] for every 10 years increase: 0.87, 95% Confidence Interval [CI], 0.81-0.94) and female radiologists had higher false-positive rates than male radiologists (OR = 1.25, 95% CI, 1.05-1.49), adjusting for patient and other radiologist characteristics. The unmeasured factors contributed to about 90% of the between-radiologist variance. Radiologists varied greatly in accuracy of mammography reading. Female and more recently trained radiologists had higher false-positive rates. The variation among radiologists was largely due to unmeasured factors, especially unmeasured radiologist factors. If our results are confirmed in further studies, they suggest that system-level interventions would be required to reduce variation in mammography interpretation.

Allegations of children's involvement in ritual sexual abuse: clinical experience of 20 cases.

PubMed

Weir, I K; Wheatcroft, M S

1995-04-01

Twenty cases were evaluated in which allegations had been made of children being involved in ritual sexual abuse (RSA). A selection of case histories are presented together with a summary of the salient points in the other cases. Using a standard format developed for assessing the validity of allegations in sexual abuse cases, it was concluded that false allegations of ritual sexual abuse occurred in three-quarters of the cases and true allegations only in one-quarter. This high rate of false allegations is unlike the author's clinical experience in other cases of child sexual abuse where the rate of false allegations is much lower and similar to other published series. Reasons for the high rate of false allegations are discussed.

Quality of malaria diagnosis and molecular confirmation of Plasmodium ovale curtisi in a rural area of the southeastern region of Ethiopia.

PubMed

Díaz, Pedro Berzosa; Lozano, Patricia Mula; Rincón, Jose Manuel Ramos; García, Luz; Reyes, Francisco; Llanes, Agustín Benito

2015-09-18

Approximately 50 million people (60 %) live in malaria risk areas in Ethiopia, at altitudes below 2000 m. According to official data, 60-70 % of malaria cases are due to Plasmodium falciparum, and 40-30 % by Plasmodium vivax. The species Plasmodium ovale was detected in 2013 in the northwest of the country, being the first report of the presence of this species in Ethiopia since the 60 s. The aim of this study was to assess the diagnosis by microscopy and PCR, and demonstrate the presence of other Plasmodium species in the country. The survey was conducted in Bulbula, situated in the Rift Valley (West Arsi Province, Oromia Region). From December 2010 to October 2011, 3060 samples were collected from patients with symptoms of malaria; the diagnosis of malaria was done by microscopy and confirmation by PCR. 736 samples were positive for malaria by microscopy. After removing the 260 samples (109 positives and 151 negatives) for which it was not possible to do PCR, there were a total of 2800 samples, 1209 are used for its confirmation by PCR and quality control (627 are positives and 582 negatives by microscopy). From the 627 positive samples, 604 were confirmed as positive by PCR, 23 false positives were detected, and the group of 582 negative samples, 184 were positive by PCR (false negatives), which added to the previous positive samples is a total of 788, positive samples for some species of Plasmodium sp. 13.3 % more positives were detected with the PCR than the microscopy. Importantly, 23 samples were detected by PCR as P. ovale, after the sequencing of these samples was determined as P. ovale curtisi. The PCR detected more positive samples than the microscopy; in addition, P. ovale and P. ovale/P. vivax were detected that had not been detected by microscopy, which can affect in the infection control.

False-positive findings in Cochrane meta-analyses with and without application of trial sequential analysis: an empirical review.

PubMed

Imberger, Georgina; Thorlund, Kristian; Gluud, Christian; Wetterslev, Jørn

2016-08-12

Many published meta-analyses are underpowered. We explored the role of trial sequential analysis (TSA) in assessing the reliability of conclusions in underpowered meta-analyses. We screened The Cochrane Database of Systematic Reviews and selected 100 meta-analyses with a binary outcome, a negative result and sufficient power. We defined a negative result as one where the 95% CI for the effect included 1.00, a positive result as one where the 95% CI did not include 1.00, and sufficient power as the required information size for 80% power, 5% type 1 error, relative risk reduction of 10% or number needed to treat of 100, and control event proportion and heterogeneity taken from the included studies. We re-conducted the meta-analyses, using conventional cumulative techniques, to measure how many false positives would have occurred if these meta-analyses had been updated after each new trial. For each false positive, we performed TSA, using three different approaches. We screened 4736 systematic reviews to find 100 meta-analyses that fulfilled our inclusion criteria. Using conventional cumulative meta-analysis, false positives were present in seven of the meta-analyses (7%, 95% CI 3% to 14%), occurring more than once in three. The total number of false positives was 14 and TSA prevented 13 of these (93%, 95% CI 68% to 98%). In a post hoc analysis, we found that Cochrane meta-analyses that are negative are 1.67 times more likely to be updated (95% CI 0.92 to 2.68) than those that are positive. We found false positives in 7% (95% CI 3% to 14%) of the included meta-analyses. Owing to limitations of external validity and to the decreased likelihood of updating positive meta-analyses, the true proportion of false positives in meta-analysis is probably higher. TSA prevented 93% of the false positives (95% CI 68% to 98%). Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Working memory affects false memory production for emotional events.

PubMed

Mirandola, Chiara; Toffalini, Enrico; Ciriello, Alfonso; Cornoldi, Cesare

2017-01-01

Whereas a link between working memory (WM) and memory distortions has been demonstrated, its influence on emotional false memories is unclear. In two experiments, a verbal WM task and a false memory paradigm for negative, positive or neutral events were employed. In Experiment 1, we investigated individual differences in verbal WM and found that the interaction between valence and WM predicted false recognition, with negative and positive material protecting high WM individuals against false remembering; the beneficial effect of negative material disappeared in low WM participants. In Experiment 2, we lowered the WM capacity of half of the participants with a double task request, which led to an overall increase in false memories; furthermore, consistent with Experiment 1, the increase in negative false memories was larger than that of neutral or positive ones. It is concluded that WM plays a critical role in determining false memory production, specifically influencing the processing of negative material.

Clinical laboratory verification of thyroglobulin concentrations in the presence of autoantibodies to thyroglobulin: comparison of EIA, radioimmunoassay and LC MS/MS measurements in an Urban Hospital.

PubMed

Wheeler, Sarah E; Liu, Li; Blair, Harry C; Sivak, Richard; Longo, Nancy; Tischler, Jeffery; Mulvey, Kathryn; Palmer, Octavia M Peck

2017-12-08

Thyroglobulin (Tg) measurements assess recurrence in post-thyroidectomy thyroid cancer patients. Tg measurements by enzyme immunoassays (EIA) can be falsely elevated by interference from Tg autoantibodies (TgAb). Radioimmunoassay (RIA) is less susceptible to TgAb interference and has been the standard-of-care test for TgAb positive patients. Recently developed liquid chromatography tandem mass spectrometry (LC-MS/MS) methods may eliminate TgAb interference. We assessed the performance of Tg measurements by EIA, RIA and LC-MS/MS to evaluate TgAb interference differences. We measured TgAb and Tg in 50 plasma samples from 40 patients in whom Tg measurement was part of their routine follow-up and 10 healthy volunteers. Discrepancy between EIA and both LC-MS/MS and RIA was observed at low Tg concentrations (≤ 7.55 ng/mL) in TgAb positive specimens (LC-MS/MS = 1.9 * EIA - 0.03, r = 0.68). RIA and LC-MS/MS Tg measurements in TgAb positive specimens with low Tg concentrations had improved correlation but demonstrated bias (LC MS/MS = 0.6 * RIA - 1.4, r = 0.90). Disagreement between methods may be attributed to LC-MS/MS reported Tg concentrations as undetectable compared to RIA. It seems likely that most discrepant cases are falsely elevated in RIA due to TgAb interference, however, some cases appear below the detection limit of LC-MS/MS; implementation of LC-MS/MS by clinicians will require lower detection limits.

Congenital syphilis: still a serious, under-diagnosed threat for children in resource-poor countries.

PubMed

Krüger, Carsten; Malleyeck, Isaack

2010-05-01

With 700,000 to 1.5 million new cases annually, congenital syphilis remains a major infectious cause of morbidity and mortality in neonates, infants and children in resource-poor countries. We therefore analyzed the extent of congenital syphilis in the pediatric patient population at our rural hospital in Tanzania. For this retrospective analysis, from January 1, 1998 to August 31, 2000, all cases of congenital syphilis were collected from the medical records of the neonatal and pediatric department at Haydom Lutheran Hospital in rural northern Tanzania. Age, sex, weight, clinical signs and symptoms, venereal disease research laboratory (VDRL) results of mother and/or child, hemoglobin concentration, treatment, and outcome were recorded and analyzed. Fourteen neonates and infants were included. The earlier the diagnosis, the more it rested on maternal data because the presentation of neonatal congenital syphilis resembled neonatal sepsis. Syphilitic skin lesions were only seen in the post-neonatal age group. VDRL results were positive in 11 of the 14 mothers, and in 4 of the infants. Anemia was common in older infants. No patient showed signs of central nervous system involvement. Two patients died, and the remaining were cured after standard treatment with procaine penicillin. Highlighting the variable picture of congenital syphilis, this report demonstrates how difficult it is to make a correct diagnosis by solely history and clinical presentation in a resource-poor setting. Hence false-positive and false-negative diagnoses are common, and clinicians have to maintain a high index of suspicion in diagnosing congenital syphilis. Therefore, an important approach to control and finally eliminate congenital syphilis as a major public health problem will be universal on-site syphilis screening of all pregnant women at their first antenatal visit and immediate treatment for those who test positive.

Evaluation of serological tests for detecting tick-borne encephalitis virus (TBEV) antibodies in animals.

PubMed

Klaus, Christine; Beer, Martin; Saier, Regine; Schubert, Harald; Bischoff, Sabine; Süss, Jochen

2011-01-01

Tick-borne encephalitis (TBE) in animals is not well understood yet. TBE virus (TBEV) serology in several host species could be valuable for epidemiological analyses in the field as well as for the detection of clinical cases. However, performance and suitability of the available test systems are not well assessed. Therefore, we evaluated two commercial TBEV-ELISA kits in a pilot study and compared them for their suitability in veterinary applications. For this purpose, we tested 163 field collected goat sera and evaluated the results by serum neutralization test (SNT) as "gold standard". Twenty-eight SNT positive sera (17.2%) were detected. The best suited ELISA kit was used for determination of a species-specific cutoff for horses, cattle, sheep, goats, pigs, mice, dogs, rabbits and monkeys with defined sera from animals without known or with improbable contact to TBEV. The level of non-specific ELISA results does not only differ between animal species but may also be influenced by the age of the tested animals. The number of sera which tested false positive by ELISA was higher in older than in young sheep. In order to obtain defined polyclonal sera as references, two dogs, cattle, goats, sheep, rabbits and pigs each, as well as one horse and 90 mice were immunized four times with a commercially available TBEV vaccine. In conclusion, our results demonstrated that commercial TBEV-ELISA kits are suitable for application in veterinary medicine for both, verification of clinical TBE cases and epidemiological screening. However, positive ELISA results should be verified by SNT. Only a very low number of false negative ELISA-results were found.

Diagnosis of adults Xp11.2 translocation renal cell carcinoma by immunohistochemistry and FISH assays: clinicopathological data from ethnic Chinese population

PubMed Central

Qu, Yuanyuan; Gu, Chengyuan; Wang, Hongkai; Chang, Kun; Yang, Xiaoqun; Zhou, Xiaoyan; Dai, Bo; Zhu, Yao; Shi, Guohai; Zhang, Hailiang; Ye, Dingwei

2016-01-01

This study aimed to assess the utility of transcription factor E3 (TFE3) break-apart fluorescence in situ hybridization (FISH) assay in diagnosis of Xp11.2 translocation renal cell carcinoma (Xp11.2 RCC) and to compare the clinicopathological features between adult Xp11.2 RCC and non-Xp11.2 RCC. 76 pathologically suspected Xp11.2 RCCs were recruited from our institution. Both TFE3 immunohistochemistry (IHC) and TFE3 FISH assay were performed for the entire cohort. The progression-free survival (PFS) and overall survival (OS) curves were estimated using the Kaplan-Meier method. FISH analysis confirmed 30 Xp11.2 RCCs, including 28 cases with positive TFE3 immunostaining and 2 cases with negative immunostaining. The false-positive and false-negative rates were 6.7% (2/30) and 4.3% (2/46), respectively, for TFE3 IHC compared with FISH assay. Xp11.2 RCC was significantly associated with higher pathological stage and Fuhrman nuclear grade compared with non-Xp11.2 RCC (P < 0.05). The median PFS and OS for TFE3 FISH-positive group were 13.0 months (95% CI, 8.4–17.6 months) and 50.0 months (95% CI, 27.6–72.4 months), respectively, while the median PFS and OS had not been reached for TFE3 FISH-negative group. In conclusion, TFE3 break-apart FISH assay is a highly useful and standard diagnostic method for Xp11.2 RCC. Adult Xp11.2 RCC is clinically aggressive and often presents at advanced stage with poor prognosis. PMID:26880493

Diagnosis of adults Xp11.2 translocation renal cell carcinoma by immunohistochemistry and FISH assays: clinicopathological data from ethnic Chinese population.

PubMed

Qu, Yuanyuan; Gu, Chengyuan; Wang, Hongkai; Chang, Kun; Yang, Xiaoqun; Zhou, Xiaoyan; Dai, Bo; Zhu, Yao; Shi, Guohai; Zhang, Hailiang; Ye, Dingwei

2016-02-16

This study aimed to assess the utility of transcription factor E3 (TFE3) break-apart fluorescence in situ hybridization (FISH) assay in diagnosis of Xp11.2 translocation renal cell carcinoma (Xp11.2 RCC) and to compare the clinicopathological features between adult Xp11.2 RCC and non-Xp11.2 RCC. 76 pathologically suspected Xp11.2 RCCs were recruited from our institution. Both TFE3 immunohistochemistry (IHC) and TFE3 FISH assay were performed for the entire cohort. The progression-free survival (PFS) and overall survival (OS) curves were estimated using the Kaplan-Meier method. FISH analysis confirmed 30 Xp11.2 RCCs, including 28 cases with positive TFE3 immunostaining and 2 cases with negative immunostaining. The false-positive and false-negative rates were 6.7% (2/30) and 4.3% (2/46), respectively, for TFE3 IHC compared with FISH assay. Xp11.2 RCC was significantly associated with higher pathological stage and Fuhrman nuclear grade compared with non-Xp11.2 RCC (P < 0.05). The median PFS and OS for TFE3 FISH-positive group were 13.0 months (95% CI, 8.4-17.6 months) and 50.0 months (95% CI, 27.6-72.4 months), respectively, while the median PFS and OS had not been reached for TFE3 FISH-negative group. In conclusion, TFE3 break-apart FISH assay is a highly useful and standard diagnostic method for Xp11.2 RCC. Adult Xp11.2 RCC is clinically aggressive and often presents at advanced stage with poor prognosis.

Outcomes and reliability of the flow coupler in postoperative monitoring of head and neck free flaps.

PubMed

Fujiwara, Rance J T; Dibble, Jacqueline M; Larson, Scott V; Pierce, Matthew L; Mehra, Saral

2018-04-01

To assess the accuracy and reliability of the flow coupler relative to the implantable arterial Doppler probe in postoperative monitoring of head and neck free flaps. Retrospective single-institution study, April 2015 to March 2017. Both the venous flow coupler and arterial Doppler were employed in 120 consecutive head and neck free flap cases. When Doppler signal loss occurred, flaps were evaluated by physical exam to determine whether signal loss was a true positive necessitating operating room takeback. Sensitivity, specificity, and false positive rate (FPR) were recorded for each device. Logistic regression was conducted to identify user trends over time. Eleven of 120 patients (9.2%) required takeback, 10 from venous thrombosis and one from arterial thrombosis. Permanent signal loss (PSL) occurred in the flow coupler in all takebacks; PSL occurred in the arterial Doppler only in the case of arterial thrombosis. Salvage rate was 9/11 (81.8%). For the flow coupler, sensitivity was 100%, specificity 86.4%, and FPR 13.6%. For the arterial probe, sensitivity was 9.1%, specificity 97.1%, and FPR 2.9%. A 4.1% decrease in false positives with each additional flow coupler use was observed. Monitoring the vein via flow coupler has high sensitivity in identifying vascular compromise compared to the arterial probe, especially for venous thrombosis. There is moderate FPR; this decreases with increased usage and, when supplemented with physical examination, does not result in unnecessary takebacks. The flow coupler can be a valuable tool in postoperative monitoring of head and neck free flaps. 4. Laryngoscope, 128:812-817, 2018. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

Evaluation of positive and false-positive results in syphilis screening of blood donors in Rio de Janeiro, Brazil.

PubMed

Sandes, V S; Silva, S G C; Motta, I J F; Velarde, L G C; de Castilho, S R

2017-06-01

We propose to analyse the positive and false-positive results of treponemal and nontreponemal tests in blood donors from Brazil and to evaluate possible factors associated with the results of treponemal tests. Treponemal tests have been used widely for syphilis screening in blood banks. The introduction of these tests in donor screening has caused an impact and a loss of donors who need to be assessed. This was a retrospective cross-sectional study of syphilis screening and confirmatory test results of blood donors that were obtained before and after adopting a chemiluminescent immunoassay (CLIA). A comparative analysis was performed using a second sample drawn from positive donors. The possible factors associated with CLIA-positive or CLIA-false-positive results were investigated in a subgroup. Statistical tests were used to compare the proportions and adjusted estimates of association. The reactivity rate increased from 1·01% (N = 28 158) to 2·66% (N = 25 577) after introducing the new test. Among Venereal Disease Research Laboratory (VDRL)- and CLIA-confirmed results, the false-positive rates were 40·5% (N = 180) and 37·4% (N = 359), respectively (P = 0·5266). Older donors (OR = 1·04; P = 0·0010) and donors with lower education levels (OR = 6·59; P = 0·0029) were associated with a higher risk of positivity for syphilis. CLIA represents an improvement in blood bank serological screening. However, its use in a healthy population appears to result in high rates of false positives. Identifying which characteristics can predict false positives, however, remains a challenge. © 2017 British Blood Transfusion Society.

A FALSE POSITIVE FOR OCEAN GLINT ON EXOPLANETS: THE LATITUDE-ALBEDO EFFECT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cowan, Nicolas B.; Abbot, Dorian S.; Voigt, Aiko

2012-06-10

Identifying liquid water on the surface of planets is a high priority, as this traditionally defines habitability. One proposed signature of oceans is specular reflection ('glint'), which increases the apparent albedo of a planet at crescent phases. We post-process a global climate model of an Earth-like planet to simulate reflected light curves. Significantly, we obtain glint-like phase variations even though we do not include specular reflection in our model. This false positive is the product of two generic properties: (1) for modest obliquities, a planet's poles receive less orbit-averaged stellar flux than its equator, so the poles are more likelymore » to be covered in highly reflective snow and ice; and (2) we show that reflected light from a modest-obliquity planet at crescent phases probes higher latitudes than at gibbous phases, therefore a planet's apparent albedo will naturally increase at crescent phase. We suggest that this 'latitude-albedo effect' will operate even for large obliquities: in that case the equator receives less orbit-averaged flux than the poles, and the equator is preferentially sampled at crescent phase. Using rotational and orbital color variations to map the surfaces of directly imaged planets and estimate their obliquity will therefore be a necessary pre-condition for properly interpreting their reflected phase variations. The latitude-albedo effect is a particularly convincing glint false positive for zero-obliquity planets, and such worlds are not amenable to latitudinal mapping. This effect severely limits the utility of specular reflection for detecting oceans on exoplanets.« less

Breast mass detection in tomosynthesis projection images using information-theoretic similarity measures

NASA Astrophysics Data System (ADS)

Singh, Swatee; Tourassi, Georgia D.; Lo, Joseph Y.

2007-03-01

The purpose of this project is to study Computer Aided Detection (CADe) of breast masses for digital tomosynthesis. It is believed that tomosynthesis will show improvement over conventional mammography in detection and characterization of breast masses by removing overlapping dense fibroglandular tissue. This study used the 60 human subject cases collected as part of on-going clinical trials at Duke University. Raw projections images were used to identify suspicious regions in the algorithm's high-sensitivity, low-specificity stage using a Difference of Gaussian (DoG) filter. The filtered images were thresholded to yield initial CADe hits that were then shifted and added to yield a 3D distribution of suspicious regions. These were further summed in the depth direction to yield a flattened probability map of suspicious hits for ease of scoring. To reduce false positives, we developed an algorithm based on information theory where similarity metrics were calculated using knowledge databases consisting of tomosynthesis regions of interest (ROIs) obtained from projection images. We evaluated 5 similarity metrics to test the false positive reduction performance of our algorithm, specifically joint entropy, mutual information, Jensen difference divergence, symmetric Kullback-Liebler divergence, and conditional entropy. The best performance was achieved using the joint entropy similarity metric, resulting in ROC A z of 0.87 +/- 0.01. As a whole, the CADe system can detect breast masses in this data set with 79% sensitivity and 6.8 false positives per scan. In comparison, the original radiologists performed with only 65% sensitivity when using mammography alone, and 91% sensitivity when using tomosynthesis alone.

Real-time hypoglycemia detection from continuous glucose monitoring data of subjects with type 1 diabetes.

PubMed

Jensen, Morten Hasselstrøm; Christensen, Toke Folke; Tarnow, Lise; Seto, Edmund; Dencker Johansen, Mette; Hejlesen, Ole Kristian

2013-07-01

Hypoglycemia is a potentially fatal condition. Continuous glucose monitoring (CGM) has the potential to detect hypoglycemia in real time and thereby reduce time in hypoglycemia and avoid any further decline in blood glucose level. However, CGM is inaccurate and shows a substantial number of cases in which the hypoglycemic event is not detected by the CGM. The aim of this study was to develop a pattern classification model to optimize real-time hypoglycemia detection. Features such as time since last insulin injection and linear regression, kurtosis, and skewness of the CGM signal in different time intervals were extracted from data of 10 male subjects experiencing 17 insulin-induced hypoglycemic events in an experimental setting. Nondiscriminative features were eliminated with SEPCOR and forward selection. The feature combinations were used in a Support Vector Machine model and the performance assessed by sample-based sensitivity and specificity and event-based sensitivity and number of false-positives. The best model was composed by using seven features and was able to detect 17 of 17 hypoglycemic events with one false-positive compared with 12 of 17 hypoglycemic events with zero false-positives for the CGM alone. Lead-time was 14 min and 0 min for the model and the CGM alone, respectively. This optimized real-time hypoglycemia detection provides a unique approach for the diabetes patient to reduce time in hypoglycemia and learn about patterns in glucose excursions. Although these results are promising, the model needs to be validated on CGM data from patients with spontaneous hypoglycemic events.

HacDivSel: Two new methods (haplotype-based and outlier-based) for the detection of divergent selection in pairs of populations

PubMed Central

2017-01-01

The detection of genomic regions involved in local adaptation is an important topic in current population genetics. There are several detection strategies available depending on the kind of genetic and demographic information at hand. A common drawback is the high risk of false positives. In this study we introduce two complementary methods for the detection of divergent selection from populations connected by migration. Both methods have been developed with the aim of being robust to false positives. The first method combines haplotype information with inter-population differentiation (FST). Evidence of divergent selection is concluded only when both the haplotype pattern and the FST value support it. The second method is developed for independently segregating markers i.e. there is no haplotype information. In this case, the power to detect selection is attained by developing a new outlier test based on detecting a bimodal distribution. The test computes the FST outliers and then assumes that those of interest would have a different mode. We demonstrate the utility of the two methods through simulations and the analysis of real data. The simulation results showed power ranging from 60–95% in several of the scenarios whilst the false positive rate was controlled below the nominal level. The analysis of real samples consisted of phased data from the HapMap project and unphased data from intertidal marine snail ecotypes. The results illustrate that the proposed methods could be useful for detecting locally adapted polymorphisms. The software HacDivSel implements the methods explained in this manuscript. PMID:28423003

Added value of diffusion-weighted MRI in detection of cervical cancer recurrence: comparison with morphologic and dynamic contrast-enhanced MRI sequences.

PubMed

Lucas, Rita; Lopes Dias, João; Cunha, Teresa Margarida

2015-01-01

We aimed to evaluate the added value of diffusion-weighted imaging (DWI) to standard magnetic resonance imaging (MRI) for detecting post-treatment cervical cancer recurrence. The detection accuracy of T2-weighted (T2W) images was compared with that of T2W MRI combined with either dynamic contrast-enhanced (DCE) MRI or DWI. Thirty-eight women with clinically suspected uterine cervical cancer recurrence more than six months after treatment completion were examined with 1.5 Tesla MRI including T2W, DCE, and DWI sequences. Disease was confirmed histologically and correlated with MRI findings. The diagnostic performance of T2W imaging and its combination with either DCE or DWI were analyzed. Sensitivity, positive predictive value, and accuracy were calculated. Thirty-six women had histologically proven recurrence. The accuracy for recurrence detection was 80% with T2W/DCE MRI and 92.1% with T2W/DWI. The addition of DCE sequences did not significantly improve the diagnostic ability of T2W imaging, and this sequence combination misclassified two patients as falsely positive and seven as falsely negative. The T2W/DWI combination revealed a positive predictive value of 100% and only three false negatives. The addition of DWI to T2W sequences considerably improved the diagnostic ability of MRI. Our results support the inclusion of DWI in the initial MRI protocol for the detection of cervical cancer recurrence, leaving DCE sequences as an option for uncertain cases.

False-positive cryptococcal antigen latex agglutination caused by disinfectants and soaps.

PubMed Central

Blevins, L B; Fenn, J; Segal, H; Newcomb-Gayman, P; Carroll, K C

1995-01-01

Five disinfectants or soaps were tested to determine if any could be responsible for false-positive results obtained with the Latex-Crypto Antigen Detection System kit (Immuno-Mycologics, Inc., Norman, Okla.). Three disinfectants or soaps (Derma soap, 7X, and Bacdown) produced false-positive agglutination after repeated washing of ring slides during testing of a known negative cerebrospinal fluid specimen. PMID:7650214

How pH, Temperature, and Time of Incubation Affect False-Positive Responses and Uncertainty of the LAL Gel-Clot Test.

PubMed

Lourenço, Felipe Rebello; Botelho, Túlia De Souza; Pinto, Terezinha De Jesus Andreoli

2012-01-01

The limulus amebocyte lysate (LAL) test is the simplest and most widely used procedure for detection of endotoxin in parenteral drugs. The LAL test demands optimal pH, ionic strength, temperature, and time of incubation. Slight changes in these parameters may increase the frequency of false-positive responses and the estimated uncertainty of the LAL test. The aim of this paper is to evaluate how changes in the pH, temperature, and time of incubation affect the occurrence of false-positive responses in the LAL test. LAL tests were performed in nominal conditions (37 °C, 60 min, and pH 7) and in different conditions of temperature (36 °C and 38 °C), time of incubation (58 and 62 min), and pH (6 and 8). Slight differences in pH increase the frequency of false-positive responses 5-fold (relative risk 5.0), resulting in an estimated of uncertainty 7.6%. Temperature and time of incubation affect the LAL test less, showing relative risks of 1.5 and 1.0, respectively. Estimated uncertainties in 36 °C or 38 °C temperatures and 58 or 62 min of incubation were found to be 2.0% and 1.0%, respectively. Simultaneous differences in these parameters significantly increase the frequency of false-positive responses. The limulus amebocyte lysate (LAL) gel-clot test is a simple test for detection of endotoxin from Gram-negative bacteria. The test is based on a gel formation when a certain amount of endotoxin is present; it is a pass/fail test. The LAL test requires optimal pH, ionic strength, temperature, and time of incubation. Slight difference in these parameters may increase the frequency of false-positive responses. The aim of this paper is to evaluate how changes in the pH, temperature, and time of incubation affect the occurrence of false-positive responses in the LAL test. We find that slight differences in pH increase the frequency of false-positive responses 5-fold. Temperature and time of incubation affect the LAL test less. Simultaneous differences in these parameters significantly increase the frequency of false-positive responses.

Automated Point Cloud Correspondence Detection for Underwater Mapping Using AUVs

NASA Technical Reports Server (NTRS)

Hammond, Marcus; Clark, Ashley; Mahajan, Aditya; Sharma, Sumant; Rock, Stephen

2015-01-01

An algorithm for automating correspondence detection between point clouds composed of multibeam sonar data is presented. This allows accurate initialization for point cloud alignment techniques even in cases where accurate inertial navigation is not available, such as iceberg profiling or vehicles with low-grade inertial navigation systems. Techniques from computer vision literature are used to extract, label, and match keypoints between "pseudo-images" generated from these point clouds. Image matches are refined using RANSAC and information about the vehicle trajectory. The resulting correspondences can be used to initialize an iterative closest point (ICP) registration algorithm to estimate accumulated navigation error and aid in the creation of accurate, self-consistent maps. The results presented use multibeam sonar data obtained from multiple overlapping passes of an underwater canyon in Monterey Bay, California. Using strict matching criteria, the method detects 23 between-swath correspondence events in a set of 155 pseudo-images with zero false positives. Using less conservative matching criteria doubles the number of matches but introduces several false positive matches as well. Heuristics based on known vehicle trajectory information are used to eliminate these.

Vision screening in preschool children: comparison of orthoptists and clinical medical officers as primary screeners.

PubMed Central

Bolger, P G; Stewart-Brown, S L; Newcombe, E; Starbuck, A

1991-01-01

OBJECTIVE--To see if there were differences in referral rates and abnormalities detected from two areas that were operating different preschool vision screening programmes. DESIGN--Cohort study using case notes of referrals. SETTING--Community based secondary referral centres in the county of Avon. PATIENTS--263 referrals from a child population of 7105 in Southmead district, an area that used orthoptists as primary vision screeners; 111 referrals from a child population of 2977 in Weston-super-Mare, an area that used clinical medical officers for screening. MAIN OUTCOME MEASURES--Amblyopia and squint detection rates, together with false positive referral rates. RESULTS--The amblyopia detection rate in Southmead district was significantly higher than in Weston-super-Mare (11/1000 children v 5/1000), as was the detection rate of squint (11/1000 v 3/1000). However, the false positive referral rate from Southmead was significantly lower than that from Weston-super-Mare (9/1000 v 23/1000). CONCLUSION--Preschool vision screening using orthoptists as primary screeners offers a more effective method of detecting visual abnormalities than using clinical medical officers. PMID:1747671

CNV detection method optimized for high-resolution arrayCGH by normality test.

PubMed

Ahn, Jaegyoon; Yoon, Youngmi; Park, Chihyun; Park, Sanghyun

2012-04-01

High-resolution arrayCGH platform makes it possible to detect small gains and losses which previously could not be measured. However, current CNV detection tools fitted to early low-resolution data are not applicable to larger high-resolution data. When CNV detection tools are applied to high-resolution data, they suffer from high false-positives, which increases validation cost. Existing CNV detection tools also require optimal parameter values. In most cases, obtaining these values is a difficult task. This study developed a CNV detection algorithm that is optimized for high-resolution arrayCGH data. This tool operates up to 1500 times faster than existing tools on a high-resolution arrayCGH of whole human chromosomes which has 42 million probes whose average length is 50 bases, while preserving false positive/negative rates. The algorithm also uses a normality test, thereby removing the need for optimal parameters. To our knowledge, this is the first formulation for CNV detecting problems that results in a near-linear empirical overall complexity for real high-resolution data. Copyright © 2012 Elsevier Ltd. All rights reserved.

Yield and Pitfalls of Ajmaline Testing in the Evaluation of Unexplained Cardiac Arrest and Sudden Unexplained Death: Single-Center Experience With 482 Families.

PubMed

Tadros, Rafik; Nannenberg, Eline A; Lieve, Krystien V; Škorić-Milosavljević, Doris; Lahrouchi, Najim; Lekanne Deprez, Ronald H; Vendrik, Jeroen; Reckman, Yolan J; Postema, Pieter G; Amin, Ahmad S; Bezzina, Connie R; Wilde, Arthur A M; Tan, Hanno L

2017-12-11

This study evaluated the yield of ajmaline testing and assessed the occurrence of confounding responses in a large cohort of families with unexplained cardiac arrest (UCA) or sudden unexplained death (SUD). Ajmaline testing to diagnose Brugada syndrome (BrS) is routinely used in the evaluation of SUD and UCA, but its yield, limitations, and appropriate dosing have not been studied in a large cohort. We assessed ajmaline test response and genetic testing results in 637 individuals from 482 families who underwent ajmaline testing for SUD or UCA. Overall, 89 individuals (14%) from 88 families (18%) had a positive ajmaline test result. SCN5A mutations were identified in 9 of 86 ajmaline-positive cases (10%). SCN5A mutation carriers had positive test results at significantly lower ajmaline doses than noncarriers (0.75 [range: 0.64 to 0.98] mg/kg vs. 1.03 [range: 0.95 to 1.14] mg/kg, respectively; p < 0.01). In 7 of 88 families (8%), it was concluded that the positive ajmaline response was a confounder, either in the presence of an alternative genetic diagnosis accounting for UCA/SUD (5 cases) or noncosegregation of positive ajmaline response and arrhythmia (2 cases). The rate of confounding responses was significantly higher in positive ajmaline responses obtained at >1 mg/kg than in those obtained at ≤1 mg/kg (7 of 48 vs. 0 of 41 individuals; Fisher's exact test: p = 0.014). In line with previous, smaller studies, a positive ajmaline response was observed in a large proportion of UCA/SUD families. Importantly, our data emphasize the potential for confounding possibly false-positive ajmaline responses in this population, particularly at high doses, which could possibly lead to a misdiagnosis. Clinicians should consider all alternative causes in UCA/SUD and avoid ajmaline doses >1 mg/kg. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Automatic Detection of Lung and Liver Lesions in 3-D Positron Emission Tomography Images: A Pilot Study

NASA Astrophysics Data System (ADS)

Lartizien, Carole; Marache-Francisco, Simon; Prost, Rémy

2012-02-01

Positron emission tomography (PET) using fluorine-18 deoxyglucose (18F-FDG) has become an increasingly recommended tool in clinical whole-body oncology imaging for the detection, diagnosis, and follow-up of many cancers. One way to improve the diagnostic utility of PET oncology imaging is to assist physicians facing difficult cases of residual or low-contrast lesions. This study aimed at evaluating different schemes of computer-aided detection (CADe) systems for the guided detection and localization of small and low-contrast lesions in PET. These systems are based on two supervised classifiers, linear discriminant analysis (LDA) and the nonlinear support vector machine (SVM). The image feature sets that serve as input data consisted of the coefficients of an undecimated wavelet transform. An optimization study was conducted to select the best combination of parameters for both the SVM and the LDA. Different false-positive reduction (FPR) methods were evaluated to reduce the number of false-positive detections per image (FPI). This includes the removal of small detected clusters and the combination of the LDA and SVM detection maps. The different CAD schemes were trained and evaluated based on a simulated whole-body PET image database containing 250 abnormal cases with 1230 lesions and 250 normal cases with no lesion. The detection performance was measured on a separate series of 25 testing images with 131 lesions. The combination of the LDA and SVM score maps was shown to produce very encouraging detection performance for both the lung lesions, with 91% sensitivity and 18 FPIs, and the liver lesions, with 94% sensitivity and 10 FPIs. Comparison with human performance indicated that the different CAD schemes significantly outperformed human detection sensitivities, especially regarding the low-contrast lesions.

Histology and culture results among subjects with antibodies to CagA but no evidence of Helicobacter pylori infection with IgG ELISA.

PubMed

Ye, Weimin; Held, Maria; Enroth, Helena; Kraaz, Wolfgang; Engstrand, Lars; Nyrén, Olof

2005-03-01

Serological evidence of antibodies to cytotoxin-associated gene A (CagA) antigens may exist without concomitant Helicobacter pylori IgG enzyme linked immunosorbent assay (ELISA) seropositivity. In a recent case-control study, this serological pattern was strongly linked to stomach cancer, and it was hypothesized to represent "burned-out" CagA-positive infections. The aim of this analysis was to test this hypothesis. We used data from a Swedish endoscopy clinic-based case-control study with 64 gastric cancer cases and 281 age-matched and gender-matched non-cancer patients who had other gastric diseases or normal endoscopy. HM-CAP ELISA and Helicoblot 2.0 immunoblot results were compared with culture and histology. Overall, 86 out of 345 (25%) subjects were CagA seropositive but ELISA seronegative. This proportion was similar among cancer and non-cancer patients. Current H. pylori infection could be verified by culture or histology in only 15% of these patients. Forty-three percent of subjects with this isolated CagA seropositivity had histological evidence of corpus and/or antral atrophy. This was higher than in those who were negative in both tests (15%), but lower than among those seropositive for both tests (53%). The percentage of isolated CagA-seropositive patients who had atrophy was similar among those with or without evidence of current infection. Although false-positive tests for CagA, or false-negative ELISA tests, may explain the serologic pattern in some of the subjects with isolated CagA seropositivity, healed infections are estimated to account for the majority. Unless the histology is often restituted after spontaneous disappearance of the infection, atrophy does not appear to be a mandatory intermediate step leading to this serology.

Frequency of Unnecessarily Biopsies among Patients with Suspicion of Prostate Cancer in Syrian Men.

PubMed

Bachour, Dala-Maria; Chahin, Emil; Al-Fahoum, Sahar

2015-01-01

The prevalence of prostate cancer is considered high in many countries, and screening tests are very important in order to detect prostate cancer in its early stages; however false positivity with these screening tests means that a lot of patients undergo unnecessary biopsy, which is an invasive procedure, for the confirmatory test. The purpose of this study was to estimate the frequency of unnecessary biopsy cases in patients referred for prostate biopsy in one of the most important and overload cancer centers in Syria. Retrospective data for a period of four years between January 2009 and December 2012 were collected in Al- Bayrouni University Medical hospital in Damascus, Syria. The patients from whom data were collected were referred to our histopathological department because of elevated prostate specific antigen (PSA) serum or an abnormal digital rectal examination (DRE). All patients underwent prostatic TRUS-guided biopsies. Diagnosis of prostate cancer (PCa) or benign prostatic hyperplasia (BPH) was based on histopathological examination and prostate cancers cases were graded and scored according to the Gleason score system. For the 406 patients referred to biopsy, the mean±SD age was 58.4 ±23.3 years. The mean ± SD PSA level was 49.2±21.5 ng/ ml. Of the total we found 237 patients diagnosed with PCa (58. 4%), 166 patients with BPH (40.9%) and 3 cases were unable to be diagnosed (0.7%) because of biopsy collection errors. Our study shows that a high percentage of patients are undergoing unnecessary biopsy, which suggests that the performed screening tests had a high level of false positive and may need re-evaluation.

The role of synovial fluid analysis in the detection of periprosthetic hip and knee infections: a systematic review and meta-analysis.

PubMed

De Fine, Marcello; Giavaresi, Gianluca; Fini, Milena; Illuminati, Andrea; Terrando, Silvio; Pignatti, Giovanni

2018-05-01

This study tried to ascertain (1) the accuracy of synovial fluid white blood cell count and polymorphonucleate percentage in the diagnosis of periprosthetic hip and knee infections, (2) which test yielded superior test performance, and (3) the influence on diagnostic accuracy of study characteristics such as patient number, study design, study level, anatomic site, and threshold value. A systematic search was conducted including papers assessing more effective cutoffs for synovial fluid tests, having comparative design, evaluating an exclusive cohort of hip or knee prostheses, including a clear definition of infected cases, and reporting sufficient data for the calculation of true-positive, false-positive, false-negative, and true-negative. A total of 375 articles were collected and, given the inclusion criteria, ten manuscripts were included. These studies assessed 1155 hip prostheses (276 infected cases) and 1235 knee prostheses (401 infected cases). The specificity of synovial fluid white blood cell count was significantly increased by using the threshold value ≥ 3000 cell/μL (p = 0.006); the sensitivity of polymorphonucleate percentage was significantly higher in detecting knee infections (p = 0.034). Both tests had a high specificity and sensitivity in detecting periprosthetic joint infections, and no clear superiority of one over the other existed. Furthermore, cutoff and anatomic site significantly influenced synovial fluid white blood cell count and polymorphonucleate percentage, respectively. Synovial fluid analysis is adequate in differentiating patients with periprosthetic hip and knee infections. Our data confirms international guidelines suggesting the use of 3000 cell/μL as cutoff threshold for synovial fluid white blood cell count. Since an anatomic site effect has been demonstrated, the goal of future studies will be to identify different cutoffs for hip and knee prostheses.

Evaluation of computer-aided diagnosis (CAD) software for the detection of lung nodules on multidetector row computed tomography (MDCT): JAFROC study for the improvement in radiologists' diagnostic accuracy.

PubMed

Hirose, Tomohiro; Nitta, Norihisa; Shiraishi, Junji; Nagatani, Yukihiro; Takahashi, Masashi; Murata, Kiyoshi

2008-12-01

The aim of this study was to evaluate the usefulness of computer-aided diagnosis (CAD) software for the detection of lung nodules on multidetector-row computed tomography (MDCT) in terms of improvement in radiologists' diagnostic accuracy in detecting lung nodules, using jackknife free-response receiver-operating characteristic (JAFROC) analysis. Twenty-one patients (6 without and 15 with lung nodules) were selected randomly from 120 consecutive thoracic computed tomographic examinations. The gold standard for the presence or absence of nodules in the observer study was determined by consensus of two radiologists. Six expert radiologists participated in a free-response receiver operating characteristic study for the detection of lung nodules on MDCT, in which cases were interpreted first without and then with the output of CAD software. Radiologists were asked to indicate the locations of lung nodule candidates on the monitor with their confidence ratings for the presence of lung nodules. The performance of the CAD software indicated that the sensitivity in detecting lung nodules was 71.4%, with 0.95 false-positive results per case. When radiologists used the CAD software, the average sensitivity improved from 39.5% to 81.0%, with an increase in the average number of false-positive results from 0.14 to 0.89 per case. The average figure-of-merit values for the six radiologists were 0.390 without and 0.845 with the output of the CAD software, and there was a statistically significant difference (P < .0001) using the JAFROC analysis. The CAD software for the detection of lung nodules on MDCT has the potential to assist radiologists by increasing their accuracy.

Intraoperative imprint cytology for evaluation of sentinel lymph nodes from Merkel cell carcinoma.

PubMed

Wong, S Lindsey; Young, Yorke D; Geisinger, Kim R; Shen, Perry; Stewart, John H; Sangueza, Omar; Pichardo-Geisinger, Rita; Levine, Edward A

2009-07-01

Merkel cell carcinoma (MCC) is a rare, aggressive cutaneous malignancy. Intraoperative imprint cytology (IIC) can potentially avoid second operations for completion lymphadenectomy when nodal metastases are found during nodal staging with sentinel lymph node biopsy (SLN). This represents the first series of IIC for MCC we are aware of and our initial experience. Patients with biopsy-proven MCC underwent SLN (at the time of wide excision) using a double indicator technique with 99technetium sulfur colloid and isosulfan blue. SLN were identified and bisected and touch imprints of each half were made. One half was air-dried and stained with Diff-Quick and the other was fixed with 95 per cent alcohol and stained with hematoxylin and eosin (H&E). Paraffin-embedded sections were examined by H&E. Eighteen patients underwent successful SLN mapping procedures. IIC was negative in 84.2 per cent (16) cases. Three false-negatives occurred with IIC, but there were no false-positives, making the sensitivity 33 per cent and the specificity 100 per cent. Two of four patients with positive pathology-confirmed SLN also had positive IIC. SLN mapping has usefulness in patients with MCC. IIC is feasible and accurate in evaluating the SLN. IIC is a practical diagnostic tool when intraoperative analysis of SLN biopsy is desired for MCC.

Evaluation of neuroendocrine tumors with 99mTc-EDDA/HYNIC TOC.

PubMed

Artiko, Vera; Afgan, Aida; Petrović, Jelena; Radović, Branislava; Petrović, Nebojša; Vlajković, Marina; Šobić-Šaranović, Dragana; Obradović, Vladimir

2016-01-01

This paper is the short review of our preliminary results obtained with 99mTc-EDDA/HYNIC-TOC. The total of 495 patients with different neuroendocrine tumors were investigated during last few years. There have been 334 true positive (TP), 73 true negative (TN), 6 false positive (FP) and 82 false negative findings (FN). Diagnosis was made according to SPECT findings in 122 patients (25%). The mean T/NT ratio for TP cases was significantly higher (p < 0.01) on SPECT (3.12 ± 1.13) than on whole body scan (2.2 ± 0.75). According to our results, overall sensitivity of the method is 80%, specificity 92%, positive predictive value 98%, negative predictive value 47% and accuracy 82%. Fifteen TP patients underwent therapy with 90Y-DOTATATE. Scintigraphy of neuroendocrine tumors with 99mTc-Tektrotyd is a useful method for diagnosis, staging and follow up of the patients suspected to have neuroendocrine tumors. SPECT had important role in diagnosis. It is also helpful in the appropriate choice of the therapy, including the peptide receptor radionuclide therapy. In the absence of 68Ga-labeled peptides and PET/CT, the special emphasize should be given to application of SPECT/CT as well as to the radioguided surgery.

False-positive result when a diphenylcarbazide spot test is used on trivalent chromium-passivated zinc surfaces.

PubMed

Reveko, Valeriia; Lampert, Felix; Din, Rameez U; Thyssen, Jacob P; Møller, Per

2018-05-01

A colorimetric 1,5-diphenylcarbazide (DPC)-based spot test can be used to identify hexavalent chromium on various metallic and leather surfaces. DPC testing on trivalent chromium-passivated zinc surfaces has unexpectedly given positive results in some cases, apparently indicating the presence of hexavalent chromium; however, the presence of hexavalent chromium has never been confirmed with more sensitive and accurate test methods. To examine the presence of hexavalent chromium on trivalent chromium-passivated zinc surfaces with a DPC-based spot test. A colorimetric DPC spot test was used for the initial detection of hexavalent chromium on new and 1-year-aged trivalent chromium-passivated zinc surfaces. Then, X-ray photoelectron spectroscopy (XPS) was performed for all samples. The DPC spot test indicated the presence of hexavalent chromium in aged, but not new, trivalent chromium passivation on zinc; however, subsequent analysis by XPS could not confirm the presence of chromium in a hexavalent state. Unintended oxidation of DPC induced by atmospheric corrosion is suggested as a possible reason for the false-positive reaction of the DPC test on a trivalent chromium-passivated zinc surface. Further validation of the use of the DPC test for chromium-containing metallic surfaces is required. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

99mTc-EDDA/HYNIC-TOC and (18)F-FDG in thyroid cancer patients with negative (131)I whole-body scans.

PubMed

Gabriel, Michael; Froehlich, Franz; Decristoforo, Clemens; Ensinger, Christian; Donnemiller, Eveline; von Guggenberg, Elisabeth; Heute, Dirk; Moncayo, Roy

2004-03-01

Several studies have reported on the expression of somatostatin receptors in patients with differentiated thyroid cancer (DTC). The aim of this study was to evaluate the imaging abilities of a recently developed technetium-99m labelled somatostatin analogue, (99m)Tc-EDDA/HYNIC-TOC ((99m)Tc-TOC), in terms of precise localisation of disease. The study population comprised 54 patients (24 men, 30 women; age range 22-90 years) with histologically confirmed DTC who presented with recurrent or persistent disease as indicated by elevated Tg levels after initial treatment. All patients were negative on the iodine-131 post-therapy whole-body scans. Fluorine-18 fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) was performed in a subgroup of 36 patients. The study population consisted of two groups: Group A ( n=22) comprised patients with disease recurrence as shown by elevated Tg levels but without detectable pathology. In group B ( n=32), pre-existing lesions were known. Among the 54 cases, SSTR scintigraphy was true positive in 33 (61.1%), true negative in 4 (7.4%) and false negative in 17 (31.5%) cases, which resulted in a sensitivity of 66%. A total of 138 tumour foci were localised in 33 patients. The fraction of true positive (99m)Tc-TOC findings was positively correlated ( P<0.01) with elevated Tg levels (higher than 30 ng/ml). Despite two false positive findings, analysis on a lesion basis demonstrated better diagnostic efficacy with (18)F-FDG PET ( P<0.001); however, it also revealed substantial agreement between the imaging techniques [Cohen's kappa of 0.62 (0.47-0.78)]. In conclusion, scintigraphy with (99m)Tc-TOC might be a promising tool for treatment planning; it is easy to perform and showed sufficient accuracy for localisation diagnostics in thyroid cancer patients with recurrent or metastatic disease.

The laboratory confirmation of suspected measles cases in settings of low measles transmission: conclusions from the experience in the Americas.

PubMed Central

Dietz, Vance; Rota, Jennifer; Izurieta, Héctor; Carrasco, Peter; Bellini, William

2004-01-01

The Americas have set a goal of interrupting indigenous transmission of measles using a strategy developed by the Pan American Health Organization (PAHO). This strategy includes recommendations for vaccination activities to achieve and sustain high immunity in the population and is complemented by sensitive epidemiological surveillance systems developed to monitor illnesses characterized by febrile rash, and to provide effective virological and serological surveillance. A key component in ensuring the success of the programme has been a laboratory network comprising 22 national laboratories including reference centres. Commercially available indirect enzyme immunoassay kits (EIA) for immunoglobulin M (IgM)-class antibodies are currently being used throughout the region. However, because there are few or no true measles cases in the region, the positive predictive value of these diagnostic tests has decreased. False-positive results of IgM tests can also occur as a result of testing suspected measles cases with exanthemata caused by Parvovirus B19, rubella and Human herpesvirus 6, among others. In addition, as countries maintain high levels of vaccination activity and increased surveillance of rash and fever, the notification of febrile rash illness in recently vaccinated people can be anticipated. Thus, managers in the measles elimination programme must be prepared to address the interpretation of a positive result of a laboratory test for measles IgM when clinical and epidemiological data may indicate that the case is not measles. The interpretation of an IgM-positive test under different circumstances and the definition of a vaccine-related rash illness in a setting of greatly reduced, or absent, transmission of measles is discussed. PMID:15640921