Bilirubin-albumin binding affinity and serum albumin concentration during intensive phototherapy (blue double light) in jaundiced newborn infants.

Thirty newborn infants with normal birth weights and uncomplicated hyperbilirubinaemia were studied. Twenty three of these were treated continuously for 24 h with intensive phototherapy (blue double light), and seven untreated infants served as controls. During the treatment the serum concentrations of total bilirubin and unbound bilirubin in diluted serum measured by the peroxidase method were markedly reduced. The binding affinity of bilirubin to its high affinity site on serum albumin was not affected. During the treatment a slight decrease of the serum albumin concentration occurred, and the possible causes of this observation are discussed.