scholarly journals Estimating Prevalence, False-Positive Rate, and False-Negative Rate with Use of Repeated Testing When True Responses Are Unknown

2007 ◽  
Vol 81 (5) ◽  
pp. 1111-1113
Author(s):  
Johanna Jakobsdottir ◽  
Daniel E. Weeks
Keyword(s):  
False Positive ◽  
False Positive Rate ◽  
False Negative ◽  
False Negative Rate ◽  
Repeated Testing ◽  
Negative Rate ◽  
Positive Rate

High Resolution CT and Bronchography in the Assessment of Bronchiectasis

1991 ◽  
Vol 32 (6) ◽  
pp. 439-441 ◽  
Author(s):  
K. Young ◽  
F. Aspestrand ◽  
A. Kolbenstvedt
Keyword(s):  
Retrospective Study ◽  
High Resolution ◽  
False Positive ◽  
False Positive Rate ◽  
False Negative ◽  
False Negative Rate ◽  
High Resolution Ct ◽  
Negative Rate ◽  
Different Types ◽  
Positive Rate

To elucidate the reliability of CT in the assessment of bronchiectasis, a retrospective study of high resolution CT and bronchography was carried out. A segment by segment comparison of 259 segmental bronchi from 70 lobes of 27 lungs in 19 patients was performed using bronchography as standard. CT was positive in 87 of 89 segmental bronchi with bronchiectasis giving a false-negative rate of 2%. CT was negative in 169 of 170 segmental bronchi without bronchiectasis at bronchography, giving a false-positive rate of 1%. There was agreement between the two modalities in identifying the different types of bronchiectasis.

scholarly journals Evaluating the usefulness of breast strain elastography for intraductal lesions

2021 ◽  
Author(s):  
Yumi Kokubu ◽  
Keiko Yamada ◽  
Masahiko Tanabe ◽  
Ayumi Izumori ◽  
Chieko Kato ◽  
...  
Keyword(s):  
False Positive ◽  
False Positive Rate ◽  
False Negative ◽  
False Negative Rate ◽  
Intraductal Papilloma ◽  
Breast Diseases ◽  
Strain Elastography ◽  
Negative Rate ◽  
Positive Rate ◽  
Sensitivity Specificity

Abstract Purpose Strain elastography for imaging lesion stiffness is being used as a diagnostic aid in the malignant/benign discrimination of breast diseases. While acquiring elastography in addition to B-mode images has been reported to help avoid performing unnecessary biopsies, intraductal lesions are difficult to discriminate whether they are malignant or benign using elastography. An objective evaluation of strain in lesions was performed in this study by measuring the elasticity index (E-index) and elasticity ratio (E-ratio) of lesions as semi-quantitative numerical indicators of the color distribution of strain. We examined whether ductal carcinoma in situ (DCIS) and intraductal papilloma could be distinguished using these semi-quantitative numerical indicators. Methods In this study, 170 ultrasonographically detected mass lesions in 162 cases (106 malignant lesions and 64 benign lesions)—in which tissue biopsy by core needle biopsy and vacuum-assisted biopsy, or surgically performed histopathological diagnosis, was performed—were selected as subjects from among 1978 consecutive cases (from January 2014 to December 2016) in which strain elastography images were acquired, in addition to standard B-mode breast ultrasonography, by measuring the E-index and E-ratio. Results The cut-off values for E-index and E-ratio in the malignant/benign discrimination of breast lesions were determined to be optimal values at 3.5 and 4.2, respectively, based on receiver operating characteristic (ROC) curve analysis. E-index sensitivity, specificity, accuracy, and AUC value (area under the curve) were 85%, 86%, 85%, and 0.860, respectively, while those for E-ratio were 78%, 74%, 74%, and 0.780, respectively. E-index yielded superior results in all aspects of sensitivity, specificity, accuracy, and AUC values, compared to those of E-ratio. The mean E-index values for malignant tumors and benign tumors were 4.46 and 2.63, respectively, indicating a significant difference (P < 0.001). E-index values of 24 DCIS lesions and 25 intraductal papillomas were 3.88 and 3.35, respectively, which showed a considerably close value, while the false-negative rate for DCIS was 29.2%, and the false-positive rate for intraductal papilloma was as high as 32.0%. Conclusion E-index in strain elastography yielded better results than E-ratio in the malignant/benign discrimination of breast diseases. On the other hand, E-index has a high false-negative rate and false-positive rate for intraductal lesions, a factor which should be taken into account when making ultrasound diagnoses.

scholarly journals Evaluation of the Sensitivity and Specificity of Two Diagnostic Tests for Antibodies to Pseudorabies Virus Glycoprotein X

1992 ◽  
Vol 4 (3) ◽  
pp. 238-244 ◽  
Author(s):  
Ronald M. Weigel ◽  
William F. Hall ◽  
Gail Scherba ◽  
Arthur M. Siegel ◽  
Edwin C. Hahn ◽  
...  
Keyword(s):  
False Positive ◽  
Pseudorabies Virus ◽  
False Positive Rate ◽  
False Negative ◽  
False Negative Rate ◽  
T Test ◽  
Serum Samples ◽  
Negative Rate ◽  
Positive Rate ◽  
The Cost

The diagnostic performance of 2 enzyme-linked immunosorbent assays (gX-T, gX-H) for antibodies to pseudorabies virus (PRV) glycoprotein X (gX) were evaluated using 311 serum samples from a nonvaccinated quarantined herd. When the standardized virus neutralization (VN) test, which uses the Shope strain (VN Shope), was used as the comparative diagnostic standard, the gX-T test had a 7% false-negative rate and a 52% false-positive rate, and the gX-H test had a 19% false-negative rate and a 19% false-positive rate. When the VN test with a Bartha recombinant strain (VN Bartha gIIIKa) was used as the diagnostic standard, the gX-T test had a 9% false-negative rate and a 26% false-positive rate, and the gX-H test had a 24% false-negative rate and a 11% false-positive rate. Thus, the gX-T test was more sensitive and the gX-H test was more specific. Additional diagnostic tests on 79 serum samples from a noninfected herd did not produce false positives for the gX-H test, but there was an 8% false-positive rate for the gX-T test. Previous studies from our laboratory have demonstrated that VN Bartha gIIIKa has higher sensitivity than VN Shope, without losing specificity, and thus is a better comparative diagnostic standard. When adding a suspect range to the gX-T test, using the same criteria as the suspect range for the gX-H test, the false-positive rate of the gX-T test was reduced to 5% when evaluated versus VN Bartha gIIIKa in the infected herd and to 1% for the PRV-negative herd. However, 18% of the positive samples were classified as suspect (vs. 8% for the gX-H test). In PRV eradication programs, the cost of false negatives is greater than the cost of false positives; thus, the gX-T diagnostic used in this study is of greater diagnostic value.

Stepwise strategies in analysing haematuria and leukocyturia in screening

2006 ◽  
Vol 44 (4) ◽  
Author(s):  
Josiane Steinmetz ◽  
Joseph Henny ◽  
René Gueguen
Keyword(s):  
Microscopic Examination ◽  
Predictive Value ◽  
False Positive ◽  
False Positive Rate ◽  
False Negative ◽  
False Negative Rate ◽  
Microscopic Analysis ◽  
Test Strip ◽  
Negative Rate ◽  
Positive Rate

AbstractThe aim of the present work was to compare in a supposed healthy population of 680 subjects several algorithms for positive selection of urine samples requiring microscopic examination for erythrocytes and leukocytes after screening by automated test-strip measurement and particle counting on a Sysmex UF-50™ flow cytometer. Four strategies have been formulated and the sensitivity, specificity, positive predictive value, negative predictive value, false positive rate, false negative rate, and microscopic review rate were measured. The strategy combining test strip analysis and automated counting on all samples, followed by microscopic examination of only discordant samples gave the best results. When the two methods of haematuria screening were in agreement (91% of samples), the false negative rate for microscopy was 1.1%, with a false positive rate of 0.8%, sensitivity of 66% and specificity of 99%, and the results are acceptable without any other examination. When the two methods of haematuria screening were discrepant, visual microscopic analysis was necessary to obtain definitive results. For leukocyturia screening, 80% of results were in agreement by test strip and automatic sediment urinalysis, with only ten results considered as false negatives (1.8%) and four as false positives (0.7%). Agreement was good and the other criteria were good (sensitivity 79%, specificity 99%). On conflicting samples, there was no agreement between methods and microscopic analysis was essential. The benefit of such an algorithm would be optimisation of the workflow without any loss of sensitivity and specificity at the expense of a two-fold increase in cost.

scholarly journals Multimodális hiperspektroszkópia – előrelépés a digitális technológia felé a méhnyakszűrésben

2021 ◽  
Vol 162 (20) ◽  
pp. 790-799
Author(s):  
Zoárd Tibor Krasznai ◽  
Zsuzsa Bagoly ◽  
Eszter Nagy ◽  
Zsolt Farkas ◽  
Róbert Póka ◽  
...  
Keyword(s):  
Human Papillomavirus ◽  
Digital Technology ◽  
Predictive Value ◽  
False Positive ◽  
False Positive Rate ◽  
False Negative ◽  
False Negative Rate ◽  
Hpv Testing ◽  
Negative Rate ◽  
Positive Rate

Összefoglaló. Bevezetés: Bevezetés: A citológiai alapú méhnyakrákszűrés átmeneti kategóriáinak optimális menedzselése a humán papillomavírus (HPV) szűrése és tipizálása ellenére jelenleg is kihívás. Vizsgálatunk célja a modern cervixspektroszkópiának (multimodális hiperspektroszkópia – MHS), egy azonnali eredményt nyújtó, digitális technológiára épülő módszernek a vizsgálata volt a citológiai alapú méhnyakszűrés találati biztonságának javítására. Betegek és módszer: Vizsgálatainkat 208, 18 és 75 év közötti nőbeteg bevonásával végeztük, akiknél már indikálásra került valamely, a méhnyakon végzendő műtét, citológiai eredményük rendelkezésre állt (a HPV-tesztet, amennyiben nem történt meg, elvégeztük), valamint valamennyi betegnél elvégeztük a műtét előtt az MHS-vizsgálatot. A szövettani mintavétel 166 betegnél történt meg. Eredmények: A citológiai vizsgálatot (az összes betegre tekintve) magas álpozitív arány jellemezte (69,28%), amely megfigyelések mindenképpen utalnak az újabb komponens alkalmazásának igényére a triázsban. Az összes citológiai kategóriára nézve az MHS-eredmények közül kiemelendő az álnegatív leletek rendkívül alacsony aránya (3/166 = 1,8%), mely a HPV-teszt esetén ennél magasabb volt (11/165 = 6,66%). A spektroszkópiás vizsgálat álpozitív aránya ugyanakkor kedvezőtlenebbnek bizonyult (91/166 = 54,81%) a HPV-vizsgálat álpozitív arányánál (40/165 = 24,24%). Az atípusos laphámsejt (ASC-US/ASC-H) citológiai kategória esetén a spektroszkópia álnegatív eredményeinek aránya (3/126 = 2,38%) szintén kedvezőbb volt, mint a HPV-vizsgálaté (9/126 = 7,14%). A cervicalis intraepithelialis neoplasia-2 vagy súlyosabb fokozatú hámelváltozások azonosításában a spektroszkópia szenzitivitása 94% (95% CI = 0,84–0,99), specificitása 22% (95% CI = 0,15–0,31), negatív prediktív értéke 90% (95% CI = 0,73–0,98), pozitív prediktív értéke 34% (95% CI = 0,26–0,43) volt (p = 0,00130). Következtetés: Az MHS fejlett innovatív technológián alapuló, azonnali eredményt adó vizsgálóeljárás, amely kiemelkedően alacsony álnegatív eredménye miatt nagy segítséget nyújt a citológiai eltéréssel rendelkező betegek további vizsgálatában. Orv Hetil. 2021; 162(20): 790–799. Summary. Introduction: Despite the use of human papillomavirus (HPV) testing, the management of the transitional categories of cytology-based screening still remains a challenge. The modern multimodal hyperspectroscopy (MHS) of the cervix is a novel digital technology based on artificial intelligence, providing an instant result in the assessment of cytology-based screening abnormalities. Patients and methods: 208 women (age 18–75) were enrolled. The patients already had cytology results and an operation on the cervix indicated at the time of inclusion. HPV and the hyperspectroscopy examination was performed pre-operatively. The pre-indicated operation was performed on 166 patients. Results: Cytology-based screening alone (in the category of all patients) resulted in a high false-positive rate (69.28%). In this category, the MHS had an outstanding false-negative rate (3/166 = 1.80%) compared to the HPV (11/165 = 6.66%). The false-positive rate of the spectroscopy examination (91/166 = 54.81%) was higher than that of the HPV testing (40/165 = 24.24%). In the atypical squamous cell (ASC-US/ASC-H) category, the false-negative rate of the spectroscopy (3/126 = 2.38%) was also lower than that of the HPV test (9/126 = 7.14%). In the detection of high-grade abnormalities (cervical intraepithelial neoplasia 2 and worse), the spectroscopy had a 94% sensitivity (95% CI = 0.84–0.99), with a 22% specificity (95% CI = 0.15–0.31), an 90% negative predictive value (95% CI = 0.73–0.98), and a 34% positive predictive value (95% CI = 0.26–0.43) (p = 0.00130). Conclusion: In the case of cytological abnormality, the MHS provides an immediate result based on advanced digital technology, and because of its outstanding false negative rate it is a great aid and should be considered in the triage of such patients. Orv Hetil. 2021; 162(20): 790–799.

Predicting the structural condition of individual sanitary sewer pipes with random forests

2014 ◽  
Vol 41 (4) ◽  
pp. 294-303 ◽  
Author(s):  
Robert Richard Harvey ◽  
Edward Arthur McBean
Keyword(s):  
Random Forests ◽  
Roc Curve ◽  
False Positive ◽  
False Positive Rate ◽  
False Negative ◽  
False Negative Rate ◽  
Structural Condition ◽  
Sewer Network ◽  
Negative Rate ◽  
Positive Rate

Closed-circuit television inspections of sewer condition deterioration as required for proactive management are expensive and hence limited to portions of a sewer network. The data mining approach presented herein is shown capable of unlocking information contained within inspection records and enhances existing pipe inspection practices currently used in the wastewater industry. Predictive models developed using the random forests algorithm are found capable of predicting individual sewer pipe condition so that uninspected pipes in a sewer network with the greatest likelihood of being in a structurally defective condition state are identified for future rounds of inspection. Complications posed by imbalance between classes common within inspection datasets are overcome by first establishing the classification task in a binary format (where pipes are in either good or bad structural condition) and then using the receiver-operating characteristic (ROC) curve to establish alternative cutoffs for the predicted class probability. The random forests algorithm achieved a stratified test set false negative rate of 18%, false positive rate of 27% and an excellent area under the ROC curve of 0.81 in a case study application to the City of Guelph, Ontario, Canada. The novel inclusion of condition information of pipes attached at either the upstream or downstream manholes of an individual pipe enhances the predictive power for bad pipes representing the minority class of interest (reducing the false negative rate to 11%, reducing the false positive rate to 25% and increasing the area under the ROC curve to 0.85). An area under the ROC curve >0.80 indicates random forests are an “excellent” choice for predicting the condition of individual pipes in a sewer network.

scholarly journals CarSite-II: an integrated classification algorithm for identifying carbonylated sites based on K-means similarity-based undersampling and synthetic minority oversampling techniques

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Yun Zuo ◽  
Jianyuan Lin ◽  
Xiangxiang Zeng ◽  
Quan Zou ◽  
Xiangrong Liu
Keyword(s):  
Reactive Oxygen Species ◽  
False Positive ◽  
False Positive Rate ◽  
False Negative ◽  
False Negative Rate ◽  
Reactive Oxygen ◽  
Support Vector ◽  
Oxygen Species ◽  
Negative Rate ◽  
Positive Rate

Abstract Background Carbonylation is a non-enzymatic irreversible protein post-translational modification, and refers to the side chain of amino acid residues being attacked by reactive oxygen species and finally converted into carbonyl products. Studies have shown that protein carbonylation caused by reactive oxygen species is involved in the etiology and pathophysiological processes of aging, neurodegenerative diseases, inflammation, diabetes, amyotrophic lateral sclerosis, Huntington’s disease, and tumor. Current experimental approaches used to predict carbonylation sites are expensive, time-consuming, and limited in protein processing abilities. Computational prediction of the carbonylation residue location in protein post-translational modifications enhances the functional characterization of proteins. Results In this study, an integrated classifier algorithm, CarSite-II, was developed to identify K, P, R, and T carbonylated sites. The resampling method K-means similarity-based undersampling and the synthetic minority oversampling technique (SMOTE-KSU) were incorporated to balance the proportions of K, P, R, and T carbonylated training samples. Next, the integrated classifier system Rotation Forest uses “support vector machine” subclassifications to divide three types of feature spaces into several subsets. CarSite-II gained Matthew’s correlation coefficient (MCC) values of 0.2287/0.3125/0.2787/0.2814, False Positive rate values of 0.2628/0.1084/0.1383/0.1313, False Negative rate values of 0.2252/0.0205/0.0976/0.0608 for K/P/R/T carbonylation sites by tenfold cross-validation, respectively. On our independent test dataset, CarSite-II yield MCC values of 0.6358/0.2910/0.4629/0.3685, False Positive rate values of 0.0165/0.0203/0.0188/0.0094, False Negative rate values of 0.1026/0.1875/0.2037/0.3333 for K/P/R/T carbonylation sites. The results show that CarSite-II achieves remarkably better performance than all currently available prediction tools. Conclusion The related results revealed that CarSite-II achieved better performance than the currently available five programs, and revealed the usefulness of the SMOTE-KSU resampling approach and integration algorithm. For the convenience of experimental scientists, the web tool of CarSite-II is available in http://47.100.136.41:8081/

scholarly journals Detection of anabolic steroid administration: ratio of urinary testosterone to epitestosterone vs the ratio of urinary testosterone to luteinizing hormone

1997 ◽  
Vol 43 (5) ◽  
pp. 731-735 ◽  
Author(s):  
Paul J Perry ◽  
John H MacIndoe ◽  
William R Yates ◽  
Shane D Scott ◽  
Timothy L Holman
Keyword(s):  
Luteinizing Hormone ◽  
Anabolic Steroid ◽  
False Positive ◽  
False Positive Rate ◽  
False Negative ◽  
False Negative Rate ◽  
Steroid Administration ◽  
Negative Rate ◽  
Positive Rate ◽  
Sensitive Marker

Abstract Our goal in this study was to determine whether the urinary ratio of testosterone to luteinizing hormone (T/LH) as an indicator of exogenous anabolic steroid (AS) use is superior to the urinary ratio of testosterone to epitestosterone (T/E). After 2 weekly placebo injections, 19 subjects were given testosterone cypionate (TC) injections of 250 or 500 mg/week for 14 weeks followed by 14 weekly placebo injections. Patients were considered to have ceased taking TC if they tested negative 9 weeks after their last injection. For detection of illicit or supraphysiological TC (AS) use, the urinary T/E ratio of ≥6 yielded a false-negative rate of 46% and a false-positive rate of 4%. However, a urinary T/LH ratio of ≥30 produced a false-negative rate of only 24% and a false-positive rate of 13%. We conclude that the urinary T/LH ratio of ≥30 is a more sensitive marker of AS use than the urinary T/E ratio of ≥6 and remains sensitive for twice as long as urinary T/E.

scholarly journals The Diagnostic Accuracy of Dehydroepiandrosterone Sulfate in Diagnosing Adrenal Insufficiency

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A97-A98
Author(s):  
Malavika Suresh ◽  
Lucinda Gruber ◽  
Irina Bancos
Keyword(s):  
Diagnostic Accuracy ◽  
Adrenal Insufficiency ◽  
False Positive ◽  
Dynamic Testing ◽  
False Positive Rate ◽  
False Negative ◽  
False Negative Rate ◽  
Dehydroepiandrosterone Sulfate ◽  
Negative Rate ◽  
Positive Rate

Abstract Background: Evaluation for adrenal insufficiency (AI) includes dynamic testing that is cumbersome, expensive, and may not always be accessible. Our objective was to evaluate the diagnostic accuracy of dehydroepiandrosterone sulfate (DHEAS) in diagnosing AI. Methods: This is a single-center retrospective study of patients evaluated for AI between July 10th, 2012 to January 7th, 2020 who underwent Cosyntropin stimulation testing (CST) or Insulin tolerance test (ITT), and had baseline measurement of DHEAS. Diagnosis of adrenal insufficiency was based on peak cortisol of &lt;18 ug/dL during either CST or ITT. Results: We identified 491 patients (379 [77.2%] women, median age 42 years [range 18–84]) who met inclusion criteria. Primary adrenal insufficiency (PAI) was diagnosed in 16 (3%) patients, secondary adrenal insufficiency (SAI) was diagnosed in 211 (43%) patients, and AI was excluded in 264 (54%) patients. CST was performed in 478 (97%) patients, ITT was done in 45 (9%) patients, with 32 patients having both CST and ITT performed. Using a peak cortisol of &lt;18 mcg/dl during CST to diagnose AI, ROC analysis of DHEAS demonstrated an area under the curve of 0.79, p&lt;0.0001. A DHEAS cutoff of 100 mcg/dL excluded AI with a sensitivity of 93%, specificity of 41%, and a false negative rate of 3%. A DHEAS cut-off of 25 mcg/dl diagnosed AI with a false positive rate of 9% (Sensitivity 57% and specificity 85%). Notably, of 32 patients who had both CST and ITT performed, the diagnosis of AI was concordant in only 5 patients, while additional 27 patients had discordant results (26 were diagnosed with SAI based on ITT, but with a normal CST, and 1 patient was diagnosed with AI on CST but not on ITT). When excluding the 27 patients with discordant results, the overall performance of DHEAS in diagnosis of AI based on CST has not changed. Conclusion: DHEAS is a valuable baseline diagnostic test for AI. DHEAS &gt;100 mcg/dl predicts a normal response during CST with a false negative rate of 3%, while DHEAS &lt;25 mcg/dl is reflective of underlying adrenal insufficiency and predicts an abnormal CST with a false positive rate of 9%. In these situations, CST can be avoided.

Pathologic Assessment of Computerized Tomography Accuracy for the Evaluation of the Laryngeal Cartilaginous Frame Work in Laryngopharyngeal Carcinomas

1989 ◽  
Vol 75 (2) ◽  
pp. 156-162 ◽  
Author(s):  
Sandro Sulfaro ◽  
Francesco Querin ◽  
Luigi Barzan ◽  
Mario Lutman ◽  
Roberto Comoretto ◽  
...  
Keyword(s):  
Computerized Tomography ◽  
False Positive ◽  
False Positive Rate ◽  
False Negative ◽  
False Negative Rate ◽  
Cartilage Destruction ◽  
High False Negative Rate ◽  
Positive Rate ◽  
Pathologic Assessment ◽  
Low Sensitivity

Sixty-six whole-organ sectioned laryngopharyngectomy specimens removed for cancer during a seven-year period were uniformly examined to determine the accuracy of preoperative high resolution computerized tomography (CT) for detection of cartilaginous involvement. Our results indicate that CT has a high overall specificity (88.2%) but a low sensitivity (47.1 %); we observed a high false-negative rate (26.5%) and a fairly low false-positive rate (5.9%). Massive cartilage destruction was easily assessed by CT, whereas both small macroscopic and microscopic neoplastic foci of cartilaginous invasion were missed on CT scans. Moreover, false-positive cases were mainly due to proximity of the tumor to the cartilage. Clinical implications of these results are discussed.

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