scholarly journals Exact inference for disease prevalence based on a test with unknown specificity and sensitivity

2022 ◽  
pp. 1-25
Author(s):  
Bryan Cai ◽  
John P. A. Ioannidis ◽  
Eran Bendavid ◽  
Lu Tian
Keyword(s):  
Disease Prevalence ◽  
Exact Inference ◽  
Specificity And Sensitivity

scholarly journals Bayesian analysis of tests with unknown specificity and sensitivity

2020 ◽  
Author(s):  
Andrew Gelman ◽  
Bob Carpenter
Keyword(s):  
Hierarchical Modeling ◽  
Disease Prevalence ◽  
Hierarchical Regression ◽  
Multilevel Regression ◽  
Statistical Adjustment ◽  
The People ◽  
Specificity And Sensitivity ◽  
Highly Sensitive ◽  
Prevalence Estimates ◽  
Representative Samples

AbstractWhen testing for a rare disease, prevalence estimates can be highly sensitive to uncertainty in the specificity and sensitivity of the test. Bayesian inference is a natural way to propagate these uncertainties, with hierarchical modeling capturing variation in these parameters across experiments. Another concern is the people in the sample not being representative of the general population. Statistical adjustment cannot with- out strong assumptions correct for selection bias in an opt-in sample, but multilevel regression and poststratification can at least adjust for known differences between the sample and the population. We demonstrate hierarchical regression and poststratification models with code in Stan and discuss their application to a controversial recent study of SARS-CoV-2 antibodies in a sample of people from the Stanford University area. Wide posterior intervals make it impossible to evaluate the quantitative claims of that study regarding the number of unreported infections. For future studies, the methods described here should facilitate more accurate estimates of disease prevalence from imperfect tests performed on non-representative samples.

Narrative Language Markers of Arabic Language Development and Impairment

2020 ◽  
Vol 63 (10) ◽  
pp. 3472-3487
Author(s):  
Natalia V. Rakhlin ◽  
Nan Li ◽  
Abdullah Aljughaiman ◽  
Elena L. Grigorenko
Keyword(s):  
Language Development ◽  
Standardized Test ◽  
Language Disorder ◽  
Arabic Language ◽  
Developmental Language Disorder ◽  
Standardized Measures ◽  
Verb Agreement ◽  
Language Groups ◽  
Specificity And Sensitivity ◽  
Omission Errors

Purpose We examined indices of narrative microstructure as metrics of language development and impairment in Arabic-speaking children. We examined their age sensitivity, correlations with standardized measures, and ability to differentiate children with average language and language impairment. Method We collected story narratives from 177 children (54.2% boys) between 3.08 and 10.92 years old ( M = 6.25, SD = 1.67) divided into six age bands. Each child also received standardized measures of spoken language (Receptive and Expressive Vocabulary, Sentence Imitation, and Pseudoword Repetition). Several narrative indices of microstructure were examined in each age band. Children were divided into (suspected) developmental language disorder and typical language groups using the standardized test scores and compared on the narrative indicators. Sensitivity and specificity of the narrative indicators that showed group differences were calculated. Results The measures that showed age sensitivity included subject omission error rate, number of object clitics, correct use of subject–verb agreement, and mean length of utterance in words. The developmental language disorder group scored higher on subject omission errors (Cohen's d = 0.55) and lower on correct use of subject–verb agreement (Cohen's d = 0.48) than the typical language group. The threshold for impaired performance with the highest combination of specificity and sensitivity was 35th percentile. Conclusions Several indices of narrative microstructure appear to be valid metrics for documenting language development in children acquiring Gulf Arabic. Subject omission errors and correct use of subject–verb agreement differentiate children with typical and atypical levels of language development.

A randomized cross-over trial in patients suspected of PAD on diagnostic accuracy of ankle-brachial index by Doppler-based versus four-point oscillometry based measurements

VASA ◽  
2019 ◽  
Vol 48 (6) ◽  
pp. 516-522 ◽  
Author(s):  
Verena Mayr ◽  
Mirko Hirschl ◽  
Peter Klein-Weigel ◽  
Luka Girardi ◽  
Michael Kundi
Keyword(s):  
Diagnostic Accuracy ◽  
Ankle Brachial Index ◽  
Area Under The Curve ◽  
High Volume ◽  
Epidemiologic Studies ◽  
Lower Sensitivity ◽  
Oscillometric Device ◽  
Specificity And Sensitivity ◽  
Time Requirements ◽  
Peripheral Arterial

Summary. Background: For diagnosis of peripheral arterial occlusive disease (PAD), a Doppler-based ankle-brachial-index (dABI) is recommended as the first non-invasive measurement. Due to limitations of dABI, oscillometry might be used as an alternative. The aim of our study was to investigate whether a semi-automatic, four-point oscillometric device provides comparable diagnostic accuracy. Furthermore, time requirements and patient preferences were evaluated. Patients and methods: 286 patients were recruited for the study; 140 without and 146 with PAD. The Doppler-based (dABI) and oscillometric (oABI and pulse wave index – PWI) measurements were performed on the same day in a randomized cross-over design. Specificity and sensitivity against verified PAD diagnosis were computed and compared by McNemar tests. ROC analyses were performed and areas under the curve were compared by non-parametric methods. Results: oABI had significantly lower sensitivity (65.8%, 95% CI: 59.2%–71.9%) compared to dABI (87.3%, CI: 81.9–91.3%) but significantly higher specificity (79.7%, 74.7–83.9% vs. 67.0%, 61.3–72.2%). PWI had a comparable sensitivity to dABI. The combination of oABI and PWI had the highest sensitivity (88.8%, 85.7–91.4%). ROC analysis revealed that PWI had the largest area under the curve, but no significant differences between oABI and dABI were observed. Time requirement for oABI was significantly shorter by about 5 min and significantly more patients would prefer oABI for future testing. Conclusions: Semi-automatic oABI measurements using the AngER-device provide comparable diagnostic results to the conventional Doppler method while PWI performed best. The time saved by oscillometry could be important, especially in high volume centers and epidemiologic studies.

Lung Function in Patients with Congenital Heart Disease: Prevalence, Severity, and Correlation to Diagnosis

2016 ◽  
Vol 64 (S 02) ◽  
Author(s):  
S. Dirks ◽  
A.-M. Ösemann ◽  
J. Woile ◽  
F. Danne ◽  
F. Berger ◽  
...  
Keyword(s):  
Congenital Heart Disease ◽  
Heart Disease ◽  
Lung Function ◽  
Congenital Heart ◽  
Disease Prevalence

How to Correct for Chance Agreement in the Estimation of Sensitivity and Specificity of Diagnostic Tests

1994 ◽  
Vol 33 (02) ◽  
pp. 180-186 ◽  
Author(s):  
H. Brenner ◽  
O. Gefeller
Keyword(s):  
Sensitivity And Specificity ◽  
Disease Status ◽  
Disease Prevalence ◽  
Small Sample ◽  
Small Samples ◽  
Interval Estimate ◽  
Traditional Concept ◽  
Interval Estimates ◽  
Major Disadvantage ◽  
Test Result

Abstract:The traditional concept of describing the validity of a diagnostic test neglects the presence of chance agreement between test result and true (disease) status. Sensitivity and specificity, as the fundamental measures of validity, can thus only be considered in conjunction with each other to provide an appropriate basis for the evaluation of the capacity of the test to discriminate truly diseased from truly undiseased subjects. In this paper, chance-corrected analogues of sensitivity and specificity are presented as supplemental measures of validity, which pay attention to the problem of chance agreement and offer the opportunity to be interpreted separately. While recent proposals of chance-correction techniques, suggested by several authors in this context, lead to measures which are dependent on disease prevalence, our method does not share this major disadvantage. We discuss the extension of the conventional ROC-curve approach to chance-corrected measures of sensitivity and specificity. Furthermore, point and asymptotic interval estimates of the parameters of interest are derived under different sampling frameworks for validation studies. The small sample behavior of the estimates is investigated in a simulation study, leading to a logarithmic modification of the interval estimate in order to hold the nominal confidence level for small samples.

Phenotyping and Genotyping of Coagulation Factor V Leiden

1996 ◽  
Vol 75 (02) ◽  
pp. 267-269 ◽  
Author(s):  
H Engel ◽  
L Zwang ◽  
H H D M van Vliet ◽  
J J Michiles ◽  
J Stibbe ◽  
...  
Keyword(s):  
Factor V Leiden ◽  
Coagulation Factor ◽  
Diagnostic Value ◽  
Resistance Test ◽  
Amplification Refractory Mutation System ◽  
Factor V ◽  
Chain Reactions ◽  
Apc Resistance ◽  
Specificity And Sensitivity ◽  
Coagulation Factor V

SummaryThe currently used activated Protein C resistance test demonstrated to be of limited diagnostic value for the detection of the mutant Factor V Leiden. Moreover, this assay is not useful for patients under anticoagulant therapy. A modification of the APC resistance test, applying Factor V deficient plasma is described which demonstrates a specificity and sensitivity of 1.0. The superiority of the modified APC resistance test over the existing APC resistance test was verified by genotyping.For that purpose, the Amplification Refractory Mutation System (ARMS) was applied to the detection of the G to A mutation at position 1691 in the gene encoding coagulation Factor V. The mutation at that position could be easily detected by using each of two allele-specific oligonucleotide primers concomitantly with one common primer in two separate polymerase chain reactions, thereby amplifying a fragment of 186 base-pairs of the Factor V gene.

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