Lipoprotein-X and other tests in the diagnosis of obstructive jaundice in the infant.

The infant with elevated direct-reacting bilirubin levels requires an early specific diagnosis to identify those who would require early surgical intervention and those in whom the bilirubin levels will eventually return to normal. This study compares the accuracy of three tests: the serum lipoprotein-X (LP-X), the I131 rose bengal (IRB) excretion and the serum alpha-fetoprotein (AFP) in making a specific diagnosis in 15 patients. When used individually the accuracy of the tests varies from 56-100%. The LP-X and IRB excretion are more specific and when in agreement are 100% acurate in the diagnosis of the neonatal hepatitis syndrome (NHS) or extrahepatic biliary obstruction (EHBO). This study suggests that both the LP-X and IRB excretion should be used in the investigation of the infant with conjugated hyperbilirubinemia.