Hypoglycemia in severely affected Rh erythroblastotic infants

Abstract

The known association of hyperbilirubinemia and kernicterus demands methods to determine an individual infant's risk of kernicterus. Indirect albumin dye binding methods (PSP or HBABA) have been used, yet these methods are of uncertain value. Study of bilirubin-albumin binding itself and a better understanding of factors which influence the binding are necessary to evaluate the risks of kernieterus. A Sephadex G-25 column (0.9 x 10 cm.) with 0.1M phosphate buffer was used to separate bound from unbound bilirubin in pooled cord sera, sera of individual infants, adult sera, and albumin solutions. The eluate contains the bilirubin-albumin complex, while the free bilirubin remains on the column. Addition of increasing amounts of bilirubin to the serum samples reveals binding characteristics of individual specimens. Infant sera bind significantly less bilirubln (bilirubin-albumin ratio of 0.9:t) than adult sera (1.12:1) or albumin solutions (1.5:1) at pH's slightly less than physiologic pH. At higher bilirubin-albumin ratios, free bilirubin remains on the column; yet contrary to other reports, additional binding still occurs. The method is easy, rapid, and permits study not only of factors influencing bilirubin-albumin binding but also the bilirubin binding capacity of the serum of an individual jaundiced infant.