FIB-4 (Fibrosis-4) Calculator

Non-invasive tool to estimate liver fibrosis severity in patients with nonalcoholic fatty liver disease (NAFLD).
FIB-4 = (Age x AST) / (PLT x √ALT)

Age (year) :
AST (U/L) :
ALT (U/L) :
Platelet (10⁹/L=10³/㎕) :
*Note on platelet unit: If the count is 230,000/μL, enter “230” only.
(Normal reference: approx. 130–440 ×10³/μL)

FIB-4 ＜ 1.3 : Low risk (90% negative predictive value)
FIB-4 1.3 ~ 2.67 : Indeterminate risk
FIB-4 ＞ 2.67 : High risk (80% positive predictive value)
※ Interpretation may be less reliable for patients under 35 or over 65 years old.

Reference :
Shah AG, Lydecker A, Murray K, Tetri BN, Contos MJ, Sanyal AJ; Nash Clinical Research Network. Comparison of noninvasive markers of fibrosis in patients with nonalcoholic fatty liver disease. Clin Gastroenterol Hepatol. 2009 Oct;7(10):1104-12. doi: 10.1016/j.cgh.2009.05.033. Epub 2009 Jun 10. PMID: 19523535; PMCID: PMC3079239.