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.