Fibrosis 4 Score (FIB-4)
( Age x AST ) / ( Plts x ( sqr ( ALT ) )
The Fibrosis 4 score is a non-invasive scoring system based on several laboratory tests (AST/ALT/Platelets) that help to non-invasively estimate the amount of scarring in the liver. This score has been studied in liver disease due to Hepatitis C and NASH.
FIB-4 below 1.30 is considered as low-risk for advanced fibrosis; a value of FIB-4 over 2.67 is considered as high-risk for advanced fibrosis; and FIB-4 values between 1.30 and 2.67 are considered as intermediate-risk of advanced fibrosis for ages 36-64. For ages > 64 the cut-off for low-risk goes to < 2.