AST to Platelet Ratio Index (APRI)

Non-invasive estimate of hepatic fibrosis and cirrhosis in chronic liver disease.

AST

U/L

AST upper limit of normal (lab-specific)

U/L

Platelet count

x10^9/L

Complete the fields above to see the result.

When to use

Non-invasive screening for significant fibrosis or cirrhosis, originally in chronic hepatitis C, before considering biopsy or elastography.

Formula

APRI = [(AST / AST upper limit of normal) x 100] / platelet count (x10^9/L). <0.5 = fibrosis unlikely; >1.5 = significant fibrosis; >=2.0 favours cirrhosis.

Pearls and pitfalls

Best validated in hepatitis C; performance is weaker in NAFLD and other aetiologies.
Endorsed by WHO as a low-cost triage tool for fibrosis assessment in hepatitis B/C in resource-limited settings.

References

Wai CT, et al. A simple noninvasive index can predict both significant fibrosis and cirrhosis in patients with chronic hepatitis C. Hepatology. 2003;38(2):518-26.