title: Quantifying the value of diagnostic tests.
abstract: This paper considers the different statistics that can be derived from studies on the value of diagnostic tests. Well-accepted quantities, such as sensitivity and specificity, are reviewed and the value of the likelihood ratio in communicating particular test results is highlighted. A new quantity, the 'diagnostic value index', is proposed and various examples of its application in nuclear medicine studies are presented. This new index is based on a weighted average of the likelihood ratios for all possible outcomes of the test, the average being weighted according to how frequently a particular outcome occurs. This index provides an objective and quantitative means of comparing the diagnostic value of different tests, or of comparing the value of a given test in different patient groups. It is hoped that this will be a useful aid to clinical decision-making concerning referrals for diagnostic tests.
authors.affiliation: Department of Nuclear Medicine, Manchester Royal Infirmary, UK.
authors.forename: J J
authors.initials: JJ
authors.lastname: Lloyd
authors.forename: P R
authors.initials: PR
authors.lastname: Talbot
authors.forename: R S
authors.initials: RS
authors.lastname: Lawson
mesh_terms: D003327:Coronary Disease / Q000175:diagnosis / Q000000981:diagnostic imaging*; D003933:Diagnosis; D004562:Electrocardiography / Q000592:standards; D005080:Exercise Test; D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D016013:Likelihood Functions; D015233:Models, Statistical; D011237:Predictive Value of Tests; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D011877:Radionuclide Imaging / Q000592:standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity