What does the NAFLD Fibrosis Score measure?

The NFS estimates the stage of liver fibrosis in patients already diagnosed with NAFLD. It does not diagnose NAFLD itself. A high score suggests advanced fibrosis (stages F3–F4), which may indicate cirrhosis or pre-cirrhotic changes.

What are the NFS cutoff values?

A score below −1.455 indicates low risk of advanced fibrosis (F0–F2, negative predictive value ~93%). A score above 0.676 indicates high risk (F3–F4, positive predictive value ~90%). Scores between these cutoffs are indeterminate and often warrant additional testing.

What is the NFS formula?

NFS = −1.675 + 0.037 × age + 0.094 × BMI + 1.13 × (IFG/diabetes: 1 if yes, 0 if no) + 0.99 × (AST÷ALT) − 0.013 × platelets (×10⁹/L) − 0.66 × albumin (g/dL).

Is this tool a substitute for a liver biopsy?

No. The NFS is a non-invasive screening aid. It helps clinicians decide whether biopsy is warranted but cannot replace histological assessment. Always interpret results in the full clinical context.

What units should I use for platelets and albumin?

Platelet count should be entered in ×10⁹/L (which is the same as 10³/µL or k/µL). Albumin should be in g/dL. If your lab reports albumin in g/L, divide by 10.

NAFLD Fibrosis Score Calculator

Name: NAFLD Fibrosis Score Calculator
Availability: InStock
Author: Nham Vu

Enter age, BMI, blood test results, and diabetes status to calculate your NAFLD Fibrosis Score and estimate liver fibrosis stage.

Patient Data

Age (years)

BMI (kg/m²)

IFG or Type 2 Diabetes?

No Yes

IFG = impaired fasting glucose (fasting glucose 100–125 mg/dL)

AST (U/L)

ALT (U/L)

Platelets (×10⁹/L)

Albumin (g/dL)

Fill in the patient data on the left and click Calculate NFS.

Summary

Enter age, BMI, blood test results, and diabetes status to calculate your NAFLD Fibrosis Score and estimate liver fibrosis stage.

How it works

Enter the patient's age in years and BMI (weight in kg divided by height in meters squared).
Select whether the patient has impaired fasting glucose (IFG) or type 2 diabetes.
Enter AST and ALT values (U/L) from a standard liver panel — the calculator derives the AST/ALT ratio.
Enter the platelet count (×10⁹/L) and serum albumin (g/dL).
Click Calculate — the NFS formula runs instantly in your browser.
The result shows the numeric score and interprets it as low (F0–F2), indeterminate, or high (F3–F4) fibrosis risk.

Use cases

Screen NAFLD patients for advanced fibrosis before considering liver biopsy.
Monitor fibrosis risk change over time with serial NFS calculations.
Support clinical decision-making in primary care and gastroenterology.
Educate patients about how metabolic factors affect liver fibrosis progression.
Compare NFS alongside other non-invasive markers (APRI, FIB-4) in clinical practice.

Frequently Asked Questions

Last updated: 2026-07-23 · Reviewed by Nham Vu