To find the optimal transcutaneous bilirubin (TcB) screening level in term neonates that minimizes the discomfort of phlebotomy, while protecting the child from harm and controlling costs.
All available TcB and total serum bilirubin (TSB) measurements taken between 27 and 51 hours of life from a cohort of term newborns were analyzed in a retrospective chart review. TcB cutoffs between 6 and 12 mg/dL were evaluated for their negative predictive values (NPVs) for high risk (HR) and for the combination of high-intermediate risk and HR on the Bhutani TSB risk nomogram.
One thousand seventy-one full-term newborns were entered into the study. Of 601 newborns with TcB <7 mg/dL, none were HR by TSB. Of newborns with a TcB of <8 mg/dL, 1 in 759 was HR. The NPVs for screening levels of 7 and 8 mg/dL were of 100% and 99.9%, respectively, for HR and 99% and 97.6%, respectively, for high-intermediate/HR. A cutoff at 12 mg/dL had NPVs of 99.3% for HR, with 7 neonates, and 92.7% for high-intermediate/HR, with 76 infants of 1041.
In our center, term infants with a TcB of <8 mg/dL may be safely discharged without a follow-up TSB, with the understanding that ~1/1000 infants may be at HR for developing severe hyperbilirubinemia. Practices with universal follow-up may safely choose cutoffs up to 12 mg/dL. An institution’s degree of comfort and confidence in follow-up of the newborn cohort will guide the choice of an appropriate TcB cutoff requiring a TSB.