A New Hour-Specific Serum Bilirubin Nomogram for Neonates ≥35 Weeks of Gestation.

OBJECTIVE: To develop a statistically rigorous, hour-specific bilirubin nomogram for newborns based on a very large data set; and use it prospectively as a replacement for the 1999 Bhutani nomogram. STUDY DESIGN: This was a retrospective analysis of first total serum bilirubin (TSB) measurements from 15 years of universal bilirubin screening during birth hospitalizations at 20 Intermountain Healthcare hospitals. Hour-specific TSB values were assembled into a nomogram by percentile, and subgroups were compared. RESULTS: The information obtained included robust data in the first 12 hours after birth (which was not included in the 1999 nomogram), general agreement with the 1999 nomogram for values in the first 60 hours, but higher 75th and 95th percentile TSB values thereafter in the new version, no difference in TSB between male and female infants, higher TSB values among earlier gestation neonates (350/7-366/7 weeks vs ≥37 weeks, P < .0001), and lower TSB values in neonates of Black race (P < .0001) and higher values in neonates of Asian race (P < .001). CONCLUSIONS: An updated and more informative Bhutani neonatal bilirubin nomogram, based on 140 times the number of subjects included the 1999 version, is now in place in our health care system.