Value of bile acid determination for the diagnosis of neonatal jaundice.

Serum concentrations of bile acids and bilirubin, and activity of alanine transferase and alkaline phosphatase as well as bile acid and bilirubin levels in duodenal contents were determined in 90 infants aged 1-44 weeks (including 49 under 10 weeks of age) admitted to hospital for prolonged jaundice. Infants with extrahepatic cholestasis were found to have statistically higher serum bile acid and bilirubin concentrations. Oral administration of cholestyramine produced a statistically significant decrease in serum bile acids and bilirubin in infants with intrahepatic cholestasis under 10 weeks of age. In 24 out of the 30 infants with biliary tract obstruction total absence of bile acids in the duodenal contents was demonstrated while in the others the concentration did not exceed 0.2 mmol/l. The mean bile acid concentration in infants with intrahepatic cholestasis was 2.81 mmol/l while in 8 infants out of the 60 bile acids were either absent or present in trace amounts. The method had an 84.4% sensitivity.