Diagnosis of extrahepatic biliary obstruction in infants by immunochemical detection of LP-X and modified 131 I-Rose Bengal excretion test.

Abstract To test for extrahepatic biliary obstruction in infants and children with persistent cholestatic liver disease, serum samples from 50 patients were examined for the presence of an abnormal low-density lipoprotein (LP-X). LP-X was identified by immunoelectrophoresis in sera from 16 infants aged 2 to 6 months and from 8 infants and children (including follow-up on 1 patient) aged 7 to 46 months with extrahepatic biliary obstruction without hepatic decompensation. However, LP-X was not found in sera from 9 patients (including follow-up on 4 patients) aged 7 to 40 months with extrahepatic biliary obstruction and hepatic decompensation. LP-X was absent in 20 of 22 infants aged 1 to 6 months with neonatal hepatitis, but was detected in the remaining 2 infants with marked intrahepatic cholestasis. These findings suggest that the LP-X test is a sensitive means for detecting the presence of severe cholestatic liver disease in infants. Results of a modified 131 I-Rose Bengal excretion test performed in 11 infants with severe cholestasis with orally administered cholestyramine, 4 Gm. per day, showed that infants with extrahepatic cholestasis excreted 7.8 per cent ± 0.6 (M ± S.E.) and those with intrahepatic cholestasis 26.2 ± 2.9 (M ± S.E.) of the administered radioactive label. The combination of LP-X and modified 131 I-Rose Bengal excretion tests represents, thus, a new diagnostic tool for identification and differentiation of extrahepatic and intrahepatic cholestasis in infants.