APRI Index

Upper Limit of Normal AST :
Platelet Count :

The APRI is used to rule-out significant fibrosis and cirrhosis in Hep C and NAFLD.

Formula :

[( AST / ULN AST ) x 100] / Platelets (109/L)]

Explanation of Result :

For NAFLD APRI values of < or = 0.3 and < or = 0.5 rule out significant fibrosis and cirrhosis, and a value of ≥ 1.5 rules in significant fibrosis. For Hepatitis C the ROC curves showed a concordance of 92% and 88.5% when 1.05 was the cut off (F3 and F4), and 87% and 83%, on 0.75 cut offs (F2-F4).”;

* Please verify all calculations prior to clinical use.


  • Wai CT1, Greenson JK, Fontana RJ, Kalbfleisch JD, Marrero JA, Conjeevaram HS, Lok AS. A simple noninvasive index can predict both significant fibrosis and cirrhosis in patients with chronic hepatitis C. Hepatology. 2003 Aug;38(2):518-26. PMID: 12883497.