Normal distribution of pre-discharge total serum bilirubin in a culturally diverse cohort of healthy term newborn infants

Abstract

Objective: To determine the percentile distribution of the pre-discharge total serum bilirubin (TSB) in a culturally diverse cohort of healthy term newborns.

Study Design: Pre-discharge TSB values obtained during the first 96 hours of life in term newborn infants with birth weight ⩾ 2,500 grams and no evidence of isoimmunization and hyperbilirubinemia (prior to and after discharge) were studied with respect to race/ethnic background and gender. The population's mean pre-discharge TSB levels and TSB percentile distribution (40th, 75th, and 95th) of the TSB values at 12-hour intervals were identified and compared with the American Academy of Pediatrics (AAP) recommended TSB nomogram. Descriptive, factorial ANOVA and multivariate regression statistics were used to analyze the results.

Results: The study included 751 healthy newborns of which 215 (28.6%) were white, 91 (12.1%) were black, 303 (40.3%) were Hispanic, and 142 (18.9%) were Asian. We found that the pre-discharge TSB values in these term healthy newborns were significantly associated with the age at TSB testing, weight loss and exclusive breastfeeding but not race/ethnicity and gender. The TSB values were mainly in the 40th percentile zone. The numbers of TSBs in the 95th percentile zone varied from 3.2% to 6.4% at the different time points of measurement. After 48 hours of age, there was a discrepancy of 1 to 2 mg/dL as compared to the AAP recommended TSB nomogram.

Conclusion: There is race/ethnicity and gender uniformity in the pre-discharge TSB levels of term healthy newborns. The observed discrepancy with the reference data suggests the need for determination of population-specific normal pre-discharge TSB values in each hospital setting for the effective post-discharge surveillance of all eligible infants.