Background: Extra-hepatic biliary atresia and several other causes of neonatal liver disease carry high mortality and morbidity rates, especially if not treated early in life. Despite professional recommendations, delayed referral of infants with prolonged jaundice continues to be a significant problem. One approach to reducing the age of referral and diagnosis is population screening to detect significant conjugated hyperbilirubinaemia as an index of liver dysfunction.
Methods: To investigate this possibility, and to provide reference data on bilirubin and its conjugated and unconjugated fractions in a normal newborn population, 1157 neonates were anonymously tested (median age 7 days, range 4-28 days) using surplus plasma from routinely collected neonatal screening specimens, using dry slide chemistry.
Results: Of 2310 specimens received, 50% were suitable for analysis. The remainder were either haemolysed or insufficient (10% and 40% of the total, respectively). Total bilirubin concentrations ranged from 9 to 428 micromol/l and conjugated bilirubin from 0 to 175 micromol/l, although the latter was rarely increased to more than 30 micromol/l (2.5th-97.5th percentile ranges 15-285 micromol/l and 0-18 micromol/l, respectively). The range of the percentage of conjugated bilirubin was 0-57% (2.5th-97.5th percentile; range 0-20%).
Conclusion: An increased conjugated bilirubin, expressed as a concentration or as the percentage of the total bilirubin, could be used as a specific marker to screen for liver dysfunction in neonates. This approach has the potential to improve the age of referral and the prognosis of infants with neonatal liver disease.