title: Comparing diagnostic tests on benefit-risk.
abstract: Comparing diagnostic tests on accuracy alone can be inconclusive. For example, a test may have better sensitivity than another test yet worse specificity. Comparing tests on benefit risk may be more conclusive because clinical consequences of diagnostic error are considered. For benefit-risk evaluation, we propose diagnostic yield, the expected distribution of subjects with true positive, false positive, true negative, and false negative test results in a hypothetical population. We construct a table of diagnostic yield that includes the number of false positive subjects experiencing adverse consequences from unnecessary work-up. We then develop a decision theory for evaluating tests. The theory provides additional interpretation to quantities in the diagnostic yield table. It also indicates that the expected utility of a test relative to a perfect test is a weighted accuracy measure, the average of sensitivity and specificity weighted for prevalence and relative importance of false positive and false negative testing errors, also interpretable as the cost-benefit ratio of treating non-diseased and diseased subjects. We propose plots of diagnostic yield, weighted accuracy, and relative net benefit of tests as functions of prevalence or cost-benefit ratio. Concepts are illustrated with hypothetical screening tests for colorectal cancer with test positive subjects being referred to colonoscopy.
authors.affiliation: a Center for Devices and Radiological Health , Food and Drug Administration , Silver Spring , Maryland , USA.
authors.forename: Gene
authors.initials: G
authors.lastname: Pennello
authors.affiliation: a Center for Devices and Radiological Health , Food and Drug Administration , Silver Spring , Maryland , USA.
authors.forename: Norberto
authors.initials: N
authors.lastname: Pantoja-Galicia
authors.affiliation: b Center for Biostatistics in AIDS Research and the Department of Biostatistics , Harvard T. H. Chan School of Public Health , Boston , Massachusetts , USA.
authors.forename: Scott
authors.initials: S
authors.lastname: Evans
mesh_terms: D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis; D003955:Diagnostic Tests, Routine; D005188:False Negative Reactions; D005189:False Positive Reactions; D006801:Humans; D015995:Prevalence; D018570:Risk Assessment; D012680:Sensitivity and Specificity
keywords: Clinical utility; cost/benefit ratio; decision theory; diagnostic yield; relative net benefit; risk threshold; weighted accuracy