🫀 APRI (AST to Platelet Ratio Index)
Estimate hepatic fibrosis non-invasively with the AST to Platelet Ratio Index (APRI).
Clinical takeaway
WHO uses APRI > 2 as a cirrhosis cut-off in resource-limited settings.
Loading calculator…
Paste the link in Slack, Teams, X, or LinkedIn — the preview image comes from this page’s Open Graph card.
When to use
Triage for fibrosis/cirrhosis where elastography is unavailable.
How it works
APRI = (AST/ULN × 100) / platelets (×10⁹/L). > 1.0 suggests significant fibrosis; > 2.0 suggests cirrhosis.
Key points
- WHO uses APRI > 2 as a cirrhosis cut-off in resource-limited settings.
- Developed in hepatitis C — performance varies by aetiology.
- Confirm with imaging/elastography where possible.
References
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| AST | 80 U/L |
|---|---|
| AST upper limit of normal | 40 U/L |
| Platelets | 150 ×10⁹/L |
→APRI1.33
- Interpretation：> 1.0 — suggests significant fibrosis
- Formula：(AST/ULN × 100) / platelets (×10⁹/L)
Frequently asked questions
- What is APRI (AST to Platelet Ratio Index)?
- Estimate hepatic fibrosis non-invasively with the AST to Platelet Ratio Index (APRI).
- How is APRI (AST to Platelet Ratio Index) calculated? What is the core formula?
- APRI = (AST/ULN × 100) / platelets (×10⁹/L). > 1.0 suggests significant fibrosis; > 2.0 suggests cirrhosis.
- When is APRI (AST to Platelet Ratio Index) used?
- Triage for fibrosis/cirrhosis where elastography is unavailable.
- What are the key clinical points for APRI (AST to Platelet Ratio Index)?
- WHO uses APRI > 2 as a cirrhosis cut-off in resource-limited settings. Developed in hepatitis C — performance varies by aetiology. Confirm with imaging/elastography where possible.
- What are the limits and cautions when using APRI (AST to Platelet Ratio Index)?
- For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
- How is APRI (AST to Platelet Ratio Index) calculated in practice? Can you show a worked example?
- Inputs: AST 80 U/L, AST upper limit of normal 40 U/L, Platelets 150 ×10⁹/L → Result: APRI 1.33（Interpretation: > 1.0 — suggests significant fibrosis, Formula: (AST/ULN × 100) / platelets (×10⁹/L)）