---
title: FIB-4 Liver Fibrosis Score Calculator
type: tool
url: "https://www.test-well.com/tools/fib-4-calculator"
date_published: 2026-09-26
free: true
---

# FIB-4 Liver Fibrosis Score Calculator

> Enter your age, AST, ALT and platelet count and the calculator returns the FIB-4 index — the non-invasive score guidelines use to sort people with fatty liver or viral hepatitis into low, indeterminate and high risk of advanced fibrosis. Below 1.3 (2.0 at 65 and over) is low risk; above 2.67 is high risk and calls for elastography or specialist review.

## Key facts

| Fact | Value |
| --- | --- |
| Inputs | Age · AST · ALT · platelets |
| Low risk | < 1.3 (< 2.0 at 65+) |
| High risk | > 2.67 |
| Cost | Free |

## For agents

See https://www.test-well.com/developers for the agent endpoints.

## Frequently asked questions

### Which blood tests give me the FIB-4 inputs?

AST and ALT are on a hepatic function panel and on a comprehensive metabolic panel; the platelet count is on any CBC. Age is the fourth input. No specialty test is needed, which is why guidelines recommend FIB-4 as the first step.

### What does an indeterminate FIB-4 mean?

Between 1.3 and 2.67 the score can neither rule advanced fibrosis in nor out. The AASLD pathway is a second-line test — liver stiffness by vibration-controlled elastography (FibroScan) or an ELF blood test — rather than a repeat FIB-4.

### Why does the cut point change at 65?

Age is in the numerator, so FIB-4 climbs with age even when the liver is fine. Using 1.3 in older adults sends too many people for further testing; McPherson and colleagues showed 2.0 preserves accuracy at 65 and over.

### Does a low FIB-4 mean I do not have fatty liver?

No. FIB-4 estimates scarring (fibrosis), not fat or inflammation. A low score in someone with fatty liver means advanced fibrosis is unlikely today; the guidance is to repeat it every one to three years while risk factors persist.

## Related

- [ast](https://www.test-well.com/biomarkers/ast)
- [alt](https://www.test-well.com/biomarkers/alt)
- [platelet count](https://www.test-well.com/biomarkers/platelet-count)
- [ggt](https://www.test-well.com/biomarkers/ggt)
- [albumin](https://www.test-well.com/biomarkers/albumin)
- [hepatic function panel](https://www.test-well.com/tests/hepatic-function-panel)
- [fatty liver panel](https://www.test-well.com/tests/fatty-liver-panel)
- [cbc with differential](https://www.test-well.com/tests/cbc-with-differential)
- [comprehensive metabolic panel](https://www.test-well.com/tests/comprehensive-metabolic-panel)

---

Canonical page: https://www.test-well.com/tools/fib-4-calculator
Machine-readable catalog: https://www.test-well.com/api/catalog.json · MCP server: https://www.test-well.com/mcp · Overview for agents: https://www.test-well.com/llms.txt

Prices are cash-pay, in USD, and include physician authorization; every order adds one flat $6 lab processing fee. Educational content is not a diagnosis — discuss results with a clinician.