AskCalc
Home › Hepatology & GI › NFS

NAFLD Fibrosis Score

The NAFLD Fibrosis Score combines age, BMI, diabetes/IFG, AST/ALT ratio, platelets and albumin to estimate advanced fibrosis in fatty liver disease. Below −1.455 advanced fibrosis is unlikely; above 0.676 it is likely; values between are indeterminate.

  • Age (years)
  • BMI
  • Impaired fasting glucose or diabetes (yes/no, +1)
  • AST (U/L)
  • ALT (U/L)
  • Platelet count (×10⁹/L or ×10³/µL)
  • Serum albumin (g/dL or g/L)
—

Interpretation

ResultMeaning
< −1.455 (< 0.12 if age ≥65)F0–F2; advanced fibrosis unlikely
−1.455 to 0.676Indeterminate
> 0.676F3–F4; advanced fibrosis likely

Formula

NFS = −1.675 + 0.037 × age + 0.094 × BMI + 1.13 × IFG/diabetes (1/0) + 0.99 × AST/ALT − 0.013 × platelets (10⁹/L) − 0.66 × albumin (g/dL)

Clinical pearls

  • In patients ≥65 years McPherson (2017) proposed a low cut-off of 0.12 to reduce false positives.
  • Albumin enters in g/dL; entering g/L without the unit gives a wildly wrong score.

Examples

nafld fibrosis score 55 yo bmi 32 diabetic ast 40 alt 50 plt 200 alb 4.2NAFLD fibrosis score: age 45, BMI 28, no diabetes, AST 25, ALT 40, platelets 280, albumin 4.5nfs 62F bmi 36 dm ast 70 alt 50 plt 130 albumin 3.5

FAQ

NAFLD fibrosis score or FIB-4?

They perform similarly; FIB-4 is simpler and is the first-line test in current MASLD guidelines.

What does an indeterminate NFS mean?

Between −1.455 and 0.676 the score cannot classify fibrosis; use transient elastography or ELF.

Evidence

  1. Angulo P et al. The NAFLD fibrosis score: a noninvasive system that identifies liver fibrosis in patients with NAFLD. Hepatology 2007;45:846–54.
  2. McPherson S et al. Age as a confounding factor for the accurate non-invasive diagnosis of advanced NAFLD fibrosis. Am J Gastroenterol 2017;112:740–51.

Hepatology & GI · Reviewed 2026-10-14 · Methodology