APRI Score Calculator

Work out apri score instantly with clear inputs, formula shown and shareable results.

About APRI Score Calculator

Divides the AST-to-upper-limit ratio by platelet count to give the AST to platelet ratio index for liver fibrosis.

Formula

APRI

APRI = (AST / AST upper limit of normal) / platelet count (10^9/L) x 100; >1.5 suggests significant fibrosis, >2.0 cirrhosis

Worked example

With the default values below, APRI Score Calculator returns APRI score of 0.833. Change any input above and every figure here is recalculated in your browser.

Inputs used

ASTaccepts 5–500 U/L: 60 U/L
AST upper limit of normalaccepts 10–80 U/L: 40 U/L
Platelet countaccepts 10–600 x10^9/L: 180 x10^9/L

Results

APRI score: 0.833
Interpretation: Indeterminate range
AST as a multiple of the upper limit: 1.50

Step by step

1Values used
2APRI
3APRI score= 0.833
4Interpretation= Indeterminate range
5AST as a multiple of the upper limit= 1.50

Assumptions and limits

The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.
This is an estimate for general information and not professional medical advice. See the full disclaimer for the limits that apply to this kind of calculator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.

Frequently Asked Questions

Why does the laboratory limit matter?

AST reference limits differ between laboratories, so using the local upper limit keeps the index comparable.

Where was APRI validated?

Chiefly in chronic hepatitis C, with reasonable performance also reported in hepatitis B and fatty liver disease.