APRI Liver Score Calculator

About this calculator

The AST-to-Platelet Ratio Index (APRI) is a non-invasive liver fibrosis screening score calculated from two numbers routinely available on a standard blood panel — AST (aspartate aminotransferase) expressed as a multiple of the upper limit of normal, divided by platelet count (in 10⁹/L), then multiplied by 100. It works on the principle that liver damage raises AST while advancing fibrosis and portal hypertension progressively lower platelet counts, so a rising ratio tracks with worsening liver disease.

Hepatologists and primary care clinicians use APRI most often in chronic hepatitis B and C patients as a first-pass alternative to liver biopsy or elastography, particularly in settings where those tools aren't readily available — a low score helps rule out significant fibrosis, while a high score flags patients who need further workup such as imaging or biopsy. It's a screening aid, not a diagnostic replacement, so results are interpreted alongside other clinical findings.

This calculator takes your AST value, the lab's upper limit of normal for AST, and your platelet count, and returns your APRI score along with which fibrosis-risk range it falls into.