#liver function tests

AST/ALT ratio

If AST is higher than ALT,amuscle source of these enzymes should be considered. For example, muscle inflammation due to dermatomyositis may cause AST>ALT. Or complete liver necrosis 

• Alcoholic fatty liver disease: AST > 8 times the ULN; ALT > 5 times the ULN
• Nonalcoholic fatty liver disease: AST and ALT > 4 times the ULN
• Acute viral hepatitis or toxin-related hepatitis with jaundice: AST and ALT > 25 times the ULN
• Ischemic hepatopathy (ischemic hepatitis, shock liver): AST and ALT > 50 times the ULN (in addition the lactate dehydrogenase is often markedly elevated)
• Chronic hepatitis C virus infection: Wide variability, typically normal to less than twice the ULN, rarely more than 10 times the ULN
• Chronic hepatitis B virus infection: Levels fluctuate; the AST and ALT may be normal, though most patients have mild to moderate elevations (approximately twice the ULN); with exacerbations, levels are more than 10 times the ULN