Differences Between Transcutaneous and Serum Bilirubin Measurements in Black African Neonates

Transcutaneous bilirubin (TcB) correlates positively with total serum bilirubin (TSB) across different racial populations. However, little is known about the pattern of divergence between TcB and TSB at individual patient-level and the relationship with TcB measuring techniques among African neonates. This study, therefore, investigates TcB-TSB discrepancies and the contribution of 2 models of transcutaneous bilirubinometers to the observed divergence in a black African population. Medical records were retrieved for late preterm and term infants with 1 to 3 pairs of TcB and TSB measurements between December 2011 to June 2015 in Nigeria. Divergence between TcB and TSB values for each infant was determined and the associated factors explored with generalized estimating equations for logistic regression. Contributions of BiliChek and JM-103 transcutaneous bilirubinometers to the divergence were further explored through linear regression and Bland-Altman analysis. Overall, 2107 TcB/TSB measurements from 1553 infants were analyzed. TSB was overestimated by ≥2 mg/dL in 64.5%, ≥3 mg/dL in 42.7%, and ≥4 mg/dL in 25.7% of all measurements. In contrast, TSB was underestimated by ≥2 mg/dL in 1.1%, ≥3 mg/dL in 0.5%, and ≥4 mg/dL in 0.3% of all recordings. Postnatal age, feeding mode, and type of TcB instrument were predictive of TSB overestimation. The JM-103 was associated with greater imprecision than BiliChek at all TSB levels. BiliChek and JM-103 bilirubinometers significantly overestimate TSB in black African neonates and may result in unnecessary or excessive treatments. Additional development of appropriate bilirubin determination devices for this racial group, especially in resource-limited settings, is warranted.