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.

Keywords

• bilirubin
• albumin
• kernicterus
• phototerapy