Tests of hepatocellular injury or cholestasis

(J Clin Transl Hepatol 2017;5:394)

詳見Elevated Liver Enzymes in Asymptomatic Patients - What Should I Do?

Aminotransferases (AST, ALT)

• intracellular enzymes released 2° necrosis/inflammation

ALT more specific for liver than is → AST (heart, skeletal muscle, kidney, brain, RBC/WBC)

↑ levels seen w/ most types of hepatocellular injury; AST >ALT → MSK injury, MI

• Alkaline phosphatase (Aϕ): enzyme bound in hepatic canalicular membrane ↑ levels seen w/ biliary obstrxn, intrahepatic cholestasis or infiltration of the liver also found in bone, intestines, kidney, placenta; confirm from liver w/: ↑ GGT (or ↑ 5′-NT)

• Bilirubin: product of heme metab (unconjugated, “indirect”) carried by alb to liver where taken up for conjugation (“direct”) to make soluble, then → excreted into bile.

• ↑ indirect hyperbili seen with hemolysis, enzymatic disorders (eg, Crigler-Najjar, Gilbert’s syndrome

• ↑ direct hyperbili seen with cholestasis, enzymatic disorders (eg, Dubin-Johnson, Rotor’s)

• jaundice seen when bili >2.5 mg/dL (esp. in sclera or under tongue); direct ↑ urine bili