Methodology of Diagnostic Tests in Hepatology

The performance of diagnostic tests can be assessed by a number of methods. These include sensitivity, specificity, positive and negative predictive values, likelihood ratios and receiver operating characteristic (ROC) curves. This paper describes the methods and explains which information they prov...

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Main Author: Erik Christensen
Format: Article
Language:English
Published: Elsevier 2009-07-01
Series:Annals of Hepatology
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S1665268119317636
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author Erik Christensen
author_facet Erik Christensen
author_sort Erik Christensen
collection DOAJ
description The performance of diagnostic tests can be assessed by a number of methods. These include sensitivity, specificity, positive and negative predictive values, likelihood ratios and receiver operating characteristic (ROC) curves. This paper describes the methods and explains which information they provide. Sensitivity and specificity provides measures of the diagnostic accuracy of a test in diagnosing the condition. The positive and negative predictive values estimate the probability of the condition from the test-outcome and the condition’s prevalence. The likelihood ratios bring together sensitivity and specificity and can be combined with the condition’s pre-test prevalence to estimate the posttest probability of the condition. The ROC curve is obtained by calculating the sensitivity and specificity of a quantitative test at every possible cut-off point between ‘normal’ and ‘abnormal’ and plotting sensitivity as a function of 1-specificity. The ROC-curve can be used to define optimal cut-off values for a test, to assess the diagnostic accuracy of the test, and to compare the usefulness of different tests in the same patients. Under certain conditions it may be possible to utilize a test’s quantitative information as such (without dichotomization) to yield diagnostic evidence in proportion to the actual test value. By combining more diagnostic tests in multivariate models the diagnostic accuracy may be markedly improved.
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spelling doaj.art-3a53d087212b405d818aa1d41eb88d822022-12-22T04:04:48ZengElsevierAnnals of Hepatology1665-26812009-07-0183177183Methodology of Diagnostic Tests in HepatologyErik Christensen0Departament of medical endocrinology and gastroenterology I, Bispebjerg Hospital, University of Copenhagen, Denmark.; Correspondence and reprint request:The performance of diagnostic tests can be assessed by a number of methods. These include sensitivity, specificity, positive and negative predictive values, likelihood ratios and receiver operating characteristic (ROC) curves. This paper describes the methods and explains which information they provide. Sensitivity and specificity provides measures of the diagnostic accuracy of a test in diagnosing the condition. The positive and negative predictive values estimate the probability of the condition from the test-outcome and the condition’s prevalence. The likelihood ratios bring together sensitivity and specificity and can be combined with the condition’s pre-test prevalence to estimate the posttest probability of the condition. The ROC curve is obtained by calculating the sensitivity and specificity of a quantitative test at every possible cut-off point between ‘normal’ and ‘abnormal’ and plotting sensitivity as a function of 1-specificity. The ROC-curve can be used to define optimal cut-off values for a test, to assess the diagnostic accuracy of the test, and to compare the usefulness of different tests in the same patients. Under certain conditions it may be possible to utilize a test’s quantitative information as such (without dichotomization) to yield diagnostic evidence in proportion to the actual test value. By combining more diagnostic tests in multivariate models the diagnostic accuracy may be markedly improved.http://www.sciencedirect.com/science/article/pii/S1665268119317636Diagnostic testSensitivitySpecificityPositive predictive valueNegative predictive valueLikelihood ratio
spellingShingle Erik Christensen
Methodology of Diagnostic Tests in Hepatology
Annals of Hepatology
Diagnostic test
Sensitivity
Specificity
Positive predictive value
Negative predictive value
Likelihood ratio
title Methodology of Diagnostic Tests in Hepatology
title_full Methodology of Diagnostic Tests in Hepatology
title_fullStr Methodology of Diagnostic Tests in Hepatology
title_full_unstemmed Methodology of Diagnostic Tests in Hepatology
title_short Methodology of Diagnostic Tests in Hepatology
title_sort methodology of diagnostic tests in hepatology
topic Diagnostic test
Sensitivity
Specificity
Positive predictive value
Negative predictive value
Likelihood ratio
url http://www.sciencedirect.com/science/article/pii/S1665268119317636
work_keys_str_mv AT erikchristensen methodologyofdiagnostictestsinhepatology