GPT and fibrosis: Indirect serum biomarkers include the Aspartate Aminotransferase-Platelet Ratio Index (APRI), fibrotest (also known as Fibrosure), FIB4 (which is calculated using age, aspartate aminotransaminase, platelet count, and alanine transaminase), Nonalcoholic Fatty Liver Disease (NAFLD) Fibrosis score, and fibroindex [5].