Abstract 977 Poster Session IV, Tuesday, 5/4 (poster 355)

Background: In spite of numerous studies, it has been difficult, if not impossible, to agree on what represents a "normal bilirubin level" in the term and near-term infant. Previous studies have shown considerable variation in the total serum bilirubin (TSB) level, depending on the racial composition of the population, the incidence of breast-feeding and other epidemiologic factors. A large international study provided a unique opportunity to reexamine this issue.

Methods: We measured TSB levels in newborn infants >35 week gestation in 9 hospitals: 5 in the U.S., 2 in Israel, and 2 in Hong Kong. A TSB was measured in 1011 infants at a mean age of 28.7 ± 3.09 hours (SD) and in 811 of the 1011 infants at 96.4 ± 6 hours.

Results: (Table)

Table 1 No caption
Full size table

Black infants and formula-fed infants had significantly lower TSB levels (vs the total population) both at ∼30 hr and 96 hr and white infants had lower TSB levels at 96 hr. Those with higher TSB levels include Asian/Pacific Islanders and partially and fully breast-fed infants at 96 hr. 72% of the total population were fully or partially breast fed versus only 52.4% of the black newborns (p= .000). This could contribute to the lower TSB found in blacks. On the other hand, as only 63.3% of the Asian newborns were breast fed this does not account for the higher TSB levels found in these infants.

Conclusions: These results confirm previous observations regarding the effect of race and feeding on TSB levels but are the first to identify significant differences by 30 hours in black and formula red infants. The data for the means and 95th percentiles provide useful benchmarks for clinicians plotting the course of jaundice in term and near term infants and can form the basis for developing guidelines for laboratory evaluation, surveillance and follow-up of the jaundiced newborn.

Supported by a grant from Natus Medical Inc., San Carlos, CA