APRI Liver Score Calculator

About this calculator

The AST-to-Platelet Ratio Index (APRI) is a non-invasive screening score for liver fibrosis and cirrhosis, calculated as APRI = [(AST ÷ AST upper limit of normal) ÷ platelet count (10⁹/L)] × 100. It works because liver fibrosis both raises AST (from ongoing liver cell damage) and lowers platelet count (from portal hypertension and reduced thrombopoietin production as liver function declines), so the ratio of the two tracks disease severity.

Hepatologists use APRI, originally validated in hepatitis C patients, as a first-line screening tool before resorting to liver biopsy or elastography — a score below roughly 0.5 makes significant fibrosis unlikely, while a score above roughly 1.5-2.0 raises concern for cirrhosis, with values in between requiring further testing. Because it only needs two common lab values, it's widely used in resource-limited settings where imaging or biopsy access is restricted.

This calculator takes your AST, its upper limit of normal, and platelet count and returns the APRI score with an interpretation.