Delta bilirubin changes following phototherapy for neonatal jaundice.

The effect of phototherapy for neonatal jaundice on the serum concentrations of total, unconjugated, conjugated and delta bilirubins were studied in 91 infants. Only unconjugated bilirubin concentration declined during phototherapy, from 254.7 +/- 7.0 mumol/l (mean +/- SD) at start to 161.4 +/- 37.4 mumol/l at cessation after 50.2 +/- 22.1 hours of exposure. Conjugated and delta bilirubin concentrations, initially already very low, were not significantly affected. Phototherapy was only efficacious for unconjugated bilirubin and did not have any effect on delta or conjugated bilirubin.