title: [Evaluation of the diagnostic value of a test. Main information indices].
abstract: Evaluating a new diagnostic test is an essential step required before using a new examination technique. The information concerning the disease provided by the test must be examined in terms of diagnostic value and cost. A test can be evaluated using several indexes. For tests giving binary results, the main information indexes were defined and the calculation of the index was illustrated by an example. The sensitivity, specificity, the Youden index, and the positive and negative predictive values were presented together with the likelihood and odds-ratio. For tests giving quantitative results, the analysis of the ROC curves was discussed. Indexes were interpreted in terms of disease prevalence, the modalities (diagnosis, screening) for applying the test, the sampling technique for the tested population, the gain in diagnosis, and cost of the examination.
authors.affiliation: Laboratoire de Biostatistique et d'Informatique médicale, Hôpital Necker, Paris.
authors.forename: P
authors.initials: P
authors.lastname: Landais
authors.forename: C
authors.initials: C
authors.lastname: Besson
authors.forename: J P
authors.initials: JP
authors.lastname: Jais
mesh_terms: D003933:Diagnosis; D003952:Diagnostic Imaging; D003955:Diagnostic Tests, Routine; D005069:Evaluation Studies as Topic; D006801:Humans; D008433:Mathematics; D008722:Methods; D011237:Predictive Value of Tests; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
vernacular_title: L'évaluation de l'apport diagnostique d'un test. Principaux indices informationnels.