Rethinking FIB-4: The hidden zonal bias in alpha-1 antitrypsin deficiency
Noninvasive fibrosis scores, particularly Fibrosis-4 (FIB-4), are widely used in hepatology due to their accessibility and simplicity.1 The FIB-4 index combines age, AST, platelet count, and ALT into a formula validated primarily in hepatitis C and metabolic dysfunction–associated steatotic liver disease, which typically cause zone III (centrilobular) hepatocyte injury and transaminase elevation.1
