FIB-4 Score Calculator
Calculate the Fibrosis-4 (FIB-4) index to assess the risk of advanced liver fibrosis. This non-invasive score uses age, AST, ALT, and platelet count.
Enter Values
Patient age in years (validated for ages 35–65)
Aspartate Aminotransferase (normal: 8–40 U/L)
Alanine Aminotransferase (normal: 7–56 U/L)
Platelet count in ×10⁹/L (normal: 150–400)
Formula:
FIB-4 = (Age × AST) / (Platelets × √ALT)
Enter all four values to calculate the FIB-4 score
FIB-4 Risk Stratification
FIB-4 < 1.30
FIB-4 1.30 – 2.67
FIB-4 > 2.67
Clinical Context & Limitations
When to Use FIB-4
First-line non-invasive test for fibrosis assessment in MASLD/NAFLD, chronic hepatitis B and C, and alcoholic liver disease. Best validated for ages 35–65.
Limitations
Less reliable in patients <35 or >65 years. May be falsely elevated in acute hepatitis flares, HIV co-infection, or conditions affecting platelet count. Not validated for post-transplant patients.
Monitoring
Recalculate FIB-4 annually for patients in the low-risk category. For indeterminate results, proceed to VCTE/FibroScan or ELF test as second-line assessment.