Bilirubin-albumin binding capacity in term and preterm infants

Abstract

Background The risk of kernicterus remains a problem in
jaundiced newborn especially in low birth weight infants.
Kernicterus can develop at low bilirubin levels. Bilirubin-albumin
binding plays an important role in its pathogenesis. Bilirubin
albumin binding concentration can also be used as the cut-off
point in the administration of phototeraphy.
Objective To determine the pattern of albumin binding
concentration in serum model in vitro and in serum of premature
and term newborn infants from cord blood sample.
Methods This study was conducted in Installation of Maternal-
Perinatal Dr. Sardjito Hospital from August-September 2004.
Blood cord samples from 20 term and 17 preterm infants were
analysed. Total bilirubin was measured spectrophotometrically and
unbound bilirubin concentration was determined by horseradish
peroxidase oxidation using UB-analyzer apparatus micromethod.
Student t test and linear regression analysis were performed.
Results Bilirubin-albumin binding capacity of term infants showed
a statistically significant difference compared to that of premature
infants (18.9±2.1 mg/dl vs 10.2±3.6 mg/dl, P<0.001). This cut-
off level approximately reflected a value of unbound bilirubin of
1 mg/dl in term and 0.5 mg/dl in premature infants.
Conclusions There is a different pattern of bilirubin-albumin
binding capacity between term and preterm infants which is higher
in term infants. Bilirubin level of 19 mg/dl and 10 mg/dl in term
and preterm newborn, respectively, can be used as cut-off point
to perform more aggressive intervention, such as phototeraphy,
and to lower the risk of kernicterus.