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Bilirubin binding contributes to the increase in total bilirubin concentration in newborns with jaundice

Charles E Ahlfors1, Anne E Parker

  • 1Department of Pediatrics, School of Medicine, Stanford University, Stanford, CA, USA. ligand@centurytel.net

Pediatrics
|August 4, 2010
PubMed

Insights

Plasma bilirubin binding avidity significantly impacts the rate of bilirubin increase in newborns. Higher binding avidity is linked to a reduced risk of bilirubin neurotoxicity, suggesting its importance in managing infant jaundice.

Area of Science:

  • Neonatal Medicine
  • Biochemistry
  • Clinical Chemistry

Background:

  • Neonatal jaundice is common, and monitoring bilirubin levels is crucial.
  • Bilirubin neurotoxicity poses a significant risk to newborns.
  • Understanding factors influencing bilirubin concentration changes is essential for effective management.

Purpose of the Study:

  • To test if the rate of increase in plasma bilirubin concentration (DeltaBT) rises with increasing bilirubin binding avidity.
  • To investigate the relationship between binding avidity and bilirubin kinetics in jaundiced newborns.

Main Methods:

  • Retrieved data on total bilirubin, unbound bilirubin, and albumin concentrations from healthy newborns (<100 hours old, >35 weeks gestation, >2.5 kg birth weight).
  • Calculated DeltaBT (mg/dL/hour) as the slope of total bilirubin versus age.
  • Quantified binding avidity as the product of albumin concentration and its bilirubin binding constant (K).
  • Used linear correlation to assess the association between DeltaBT and binding avidity (K.albumin concentration).

Main Results:

  • Studied 21 patients with ranges: total bilirubin (7.6–28.5 mg/dL), unbound bilirubin (0.53–2.52 µg/dL), albumin (2.9–4.6 g/dL), and K (38–163 L/µmol).
  • Found a significant correlation between DeltaBT and K.albumin concentration (r²=0.23; P=.026).

Conclusions:

  • Plasma bilirubin binding avidity is a significant contributor to DeltaBT.
  • This binding avidity component is associated with a lower risk of bilirubin neurotoxicity.
  • Incorporating binding avidity measurements into jaundice management algorithms warrants further study.
Abstract

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