Table 2

Biochemical features of acute viral hepatitis

TestNotes
Serum aminotransferases (ALT, AST)Typically peaks at 500–10000 IU/l in the first few weeks.
Serum bilirubin30–100 μmol/l. Mixed conjugated/unconjugated with bilirubinuria. Prolonged jaundice with rising bilirubin is seen in patients with the cholestatic variant. Beware other serious causes of acute jaundice in the tropics such as malaria, yellow fever and typhoid, all of which are usually accompanied by fever—a fever is normally absent in icteric viral hepatitis
Serum alkaline phosphataseUsually normal or only mildly raised (<300 IU/l) except in the uncommon cholestatic variant of acute viral hepatitis. Epstein-Barr virus related hepatitis often presents with a moderately raised serum alkaline phosphatase level (300–500 IU/l) and aminotransferase levels <1000 IU/l. Very high alkaline phosphatase levels suggest biliary tract disease.
Prothrombin timeMay be slightly prolonged by 1–5 seconds. Prolongation >5 seconds (INR >1.5) suggest impending hepatic failure.