Steatosis-Associated Fibrosis Estimator (SAFE) score

Age

years

Body mass index (BMI)

kg/m²

Diabetes mellitus

Aspartate aminotransferase (AST)

U/L

Alanine aminotransferase (ALT)

U/L

Total serum protein

g/dL

Albumin

Platelet count

×10⁹/L

Complete the fields above to see the result.

When to use

First-line, labs-only screening for clinically significant fibrosis in patients with suspected or known MASLD/NAFLD in primary care.

Formula

SAFE = 2.97×age + 5.99×BMI(capped at 40) + 62.85×diabetes(0/1) + 154.85×ln(AST) − 58.23×ln(ALT) + 195.48×ln(globulin) − 141.61×ln(platelets ×10⁹/L) − 75, where globulin = total protein − albumin (g/dL). SAFE <0 = low risk, 0–100 = intermediate risk, ≥100 = high risk of stage ≥F2 fibrosis.

Pearls and pitfalls

Outperformed FIB-4 and the NAFLD Fibrosis Score for detecting stage ≥F2 fibrosis in the derivation and validation cohorts.
BMI values above 40 kg/m² are capped at 40 in the equation.

References

Sanyal AJ, et al. The steatosis-associated fibrosis estimator (SAFE) score: A tool to detect low-risk NAFLD in primary care. Hepatology. 2023;77(1):256-267.