Skip to main content
Clinical reference calculator Β· GeraClinic

NAFLD Fibrosis Score (NFS) Calculator

The NAFLD Fibrosis Score (NFS) estimates the likelihood of advanced liver fibrosis in non-alcoholic fatty liver disease from age, BMI, glucose status, AST/ALT, platelets and albumin.

Quick answer

The NAFLD Fibrosis Score (NFS) estimates advanced liver fibrosis in non-alcoholic fatty liver disease from age, BMI, impaired fasting glucose or diabetes, the AST/ALT ratio, platelets and albumin. A score below βˆ’1.455 makes advanced fibrosis unlikely, above 0.676 makes it likely, and values in between are indeterminate.

NAFLD Fibrosis Score inputs

Validated formula

NFS = βˆ’1.675 + 0.037 Γ— age (years) + 0.094 Γ— BMI (kg/mΒ²) + 1.13 Γ— (IFG or diabetes: yes=1, no=0) + 0.99 Γ— (AST/ALT ratio) βˆ’ 0.013 Γ— platelet count (Γ—10⁹/L) βˆ’ 0.66 Γ— albumin (g/dL).

Interpretation

  • < βˆ’1.455β€” Low probability β€” advanced fibrosis (F3–F4) excluded with high accuracy (NPV ~88–93%).
  • βˆ’1.455 to 0.676β€” Indeterminate β€” advanced fibrosis cannot be confidently confirmed or excluded.
  • > 0.676β€” High probability of advanced fibrosis (F3–F4) (PPV ~82–90%).

How to use the NAFLD Fibrosis Score calculator

  1. 1Enter the variables. Enter age, BMI, AST, ALT, platelet count and albumin, and tick impaired fasting glucose or diabetes if present.
  2. 2Read the score. The tool applies the published NFS regression and shows the result.
  3. 3Interpret the band. Below βˆ’1.455 advanced fibrosis is excluded with high accuracy, above 0.676 it is likely, and the middle zone is indeterminate and usually prompts further assessment.

Medical disclaimer: This is general health information, not medical advice. It does not diagnose or treat any condition, and the results are estimates based on public reference formulas. Always consult a qualified doctor about your individual health. If you think you may have a medical emergency, contact your local emergency services immediately.

Talk to a doctor

Get a professional evaluation from a verified doctor by video, audio, or chat β€” available across 60+ countries on GeraClinic.

Book a consultation

Frequently asked questions

What NFS value rules out advanced fibrosis?βŒ„

A score below βˆ’1.455 excludes advanced fibrosis (F3–F4) with a high negative predictive value (around 88–93%). A clinician interprets it alongside other findings.

What does an indeterminate NFS mean?βŒ„

A score between βˆ’1.455 and 0.676 cannot confidently confirm or exclude advanced fibrosis. This commonly leads to further testing such as elastography or a second non-invasive marker.

Does NFS replace a liver biopsy?βŒ„

No. It is a non-invasive screening score that helps decide who needs more testing. Definitive staging may still require imaging or biopsy as judged by a specialist.

Sources & validation

This calculator reproduces the published NAFLD Fibrosis Score score, validated for advanced fibrosis (F3–F4) in non-alcoholic fatty liver disease.

Related clinical calculators

MELD 3.0Child-PughFIB-4

Need to discuss a result? Find and book a verified doctor on GeraClinic.