Validation and comparison of RPR, the models, AAR, FIB-4 and APRI for the prediction of fibrosis stages in the validation patients.

The cutoffs described in the original reports were used for all calculations. For AAR, Metavir stage F4 in our study was compared with the presence of cirrhosis in the Giannini study [20]; for FIB-4, Metavir stages F3–F4 in our study were compared with the presence of advanced fibrosis (Ishak stages F4–F6) in the Richard K study [21]; and for APRI, Metavir stages F2–F4 in our study were compared with the presence of significant fibrosis (Ishak stages F3–F6), and F4 was compared with the presence of cirrhosis (Ishak stages F5–F6) in the Wai study [7].
RPR: RDW-to-platelet ratio; AAR: AST-to-ALT ratio; APRI: AST-to-platelet ratio index; Sen: sensitivity; Spe: specificity; PPV: positive predictive value; NPV: negative predictive value.