Statistical methods for evidence-based medicine: the diagnostic test. Part II.
Part II of this work addresses the use of likelihood ratios for the calculation of a positive predictive value (PPV) and a negative predictive value (NPV) for patient diagnosis. These two values are the most useful indices in the application of a diagnostic test in order to make a diagnosis for a patient. Furthermore, the relevance of sample size is also addressed by providing background theory and pertinent tables. These basic topics for assessing the validity of a diagnostic test and for performing appropriate and valid case vs control studies are explained in a simple way for a clinical audience with a working example.
Antonelli
P
P
Medical Statistics and Biometry Unit, Department of Biomedical Sciences and Biotechnologies, University of Brescia, Brescia, Italy.
Chiumello
D
D
Cesana
B M
BM
D003955:Diagnostic Tests, Routine / Q000706:statistics & numerical data*; D019317:Evidence-Based Medicine; D011237:Predictive Value of Tests; D012372:ROC Curve; D018401:Sample Size