Increasing incidence of moderate neonatal hyperbilirubinaemia in Wirral

Neonatal jaundice: a critical review of the role and practice of bilirubin analysis

Neonatal jaundice is common, and usually harmless, because of physiological jaundice or breast-feeding. In some neonates unconjugated bilirubin concentration, coupled with other risk factors, is sufficient to allow free bilirubin to cross the blood-brain barrier and cause kernicterus. Another subgroup of infants is jaundiced because of elevated conjugated bilirubin; a marker for a number of pathological conditions. Bilirubin measurement must identify those infants at risk. Transcutaneous bilirubin measurement is increasingly used in healthy infants, especially before early discharge or at home, to assess the need for laboratory bilirubin measurement. Transcutaneous measurements are not covered by laboratory quality assessment schemes. Guidelines on management of neonatal jaundice utilize age in hours and other risk factors to define bilirubin action thresholds, which may be as low as 100 μmol/L for sick premature infants, whereas early discharged babies may only present after bilirubin concentrations are extremely high. Hence, there is a requirement for accurate total bilirubin measurement from <100 to >500 μmol/L, with sufficient precision to assess the rate of bilirubin change with time. Babies presenting with late jaundice always require conjugated bilirubin measurement. It is of concern that many total and direct bilirubin automated kit methods suffer from haemolysis interference, while use of in-house methods or modification of commercial methods has virtually disappeared. External quality assessment has a vital role in providing data on different methods' performance, including accuracy, precision and susceptibility to interference. Laboratories should consider whether their adult bilirubin methods are suitable for neonates.

Prospective surveillance study of severe hyperbilirubinaemia in the newborn in the UK and Ireland

OBJECTIVES

To determine the incidence of severe hyperbilirubinaemia in the newborn, and to identify associated clinical and demographic variables, and short-term outcomes.

DESIGN

Prospective, population-based study.

SETTING

UK and Republic of Ireland, between 1 May 2003 and 31 May 2005.

PARTICIPANTS

Infants in the first month of life with severe hyperbilirubinaemia (maximum unconjugated serum bilirubin >/=510 micromol/l).

RESULTS

108 infants met the case definition, 106 from the UK and 2 from the Republic of Ireland. The UK incidence of severe hyperbilirubinaemia was 7.1/100 000 live births (95% CI 5.8 to 8.6). Only 20 cases presented in hospital; 88 were admitted with severe jaundice. 64 (60.4%) cases were male, and 56 (51.8%) were of ethnic minority origin. 87 (80.5%) cases were exclusively breast fed. Co-morbidity included haemolysis, dehydration, infection and bruising. 14 infants showed evidence of bilirubin encephalopathy, of whom 3 died. The UK incidence of bilirubin encephalopathy was 0.9/100 000 live births (95% CI 0.46 to 1.5).

CONCLUSIONS

This is the first large, prospective, population-based study of the incidence of severe hyperbilirubinaemia in the newborn. The clinical and demographic associations, and short-term outcomes identified, are the same as those reported recently in North America and Europe.