Absence of bilirubin binding competitors during phototherapy for neonatal jaundice.

Bilirubin-albumin binding was quantitated (peroxidase method) before, during, and after phototherapy in 21 jaundiced infants. Binding was analyzed at two different serum dilutions (1:1.8 and 1:57) to determine whether binding competitors are present during phototherapy. No significant changes in binding were found at either dilution during phototherapy, regardless of birthweight, gestational age, or illness. Serum binding of bilirubin does not appear to be altered during phototherapy.