Transcutaneous versus Total Serum Bilirubin Measurements in Preterm Infants
Thivia Jegathesan, Douglas M. Campbell, Joel G. Ray, Vibhuti Shah, Howard Berger, Robin Z. Hayeems, Michael Sgro, for the NeoHBC
Abstract
INTRODUCTION: Transcutaneous bilirubin (TcB) measurement offers a noninvasive approach for bilirubin screening; however, its accuracy in preterm infants is unclear. This study determined the agreement between TcB and total serum bilirubin (TSB) among preterm infants. METHODS: A multisite prospective cohort study was conducted at 3 NICUs in Ontario, Canada, September 2016 to June 2018. Among 296 preterm infants born at 240/7 to 356/7 weeks, 856 TcB levels were taken at the forehead, sternum, and before and after the initiation of phototherapy with TSB measurements. Bland-Altman plots and 95% limits of agreement (LOA) expressed agreement between TcB and TSB. RESULTS: The overall mean TcB-TSB difference was -24.5 μmol/L (95% LOA -103.3 to 54.3), 1.6 μmol/L (95% LOA -73.4 to 76.5) before phototherapy, and -31.1 μmol/L (95% LOA -105.5 to 43.4) after the initiation of phototherapy. The overall mean TcB-TSB difference was -15.2 μmol/L (95% LOA -86.8 to 56.3) at the forehead and -24.4 μmol/L (95% LOA -112.9 to 64.0) at the sternum. The mean TcB-TSB difference was -31.4 μmol/L (95% LOA -95.3 to 32.4) among infants born 24-28 weeks, -25.5 μmol/L (95% LOA -102.7 to 51.8) at 29-32 weeks, and -15.9 μmol/L (95% LOA -107.4 to 75.6) at 33-35 weeks. Measures did not differ by maternal ethnicity. CONCLUSION: Among preterm infants, TcB may offer a noninvasive, immediate approach to screening for hyperbilirubinemia with more careful use in preterm infants born at <33 weeks' gestation, as TcB approaches treatment thresholds. Its underestimation of TSB after the initiation of phototherapy warrants the use of TSB for clinical decision-making after the initiation of phototherapy.