Plotting Transcutaneous Bilirubin Measurements on Specific Transcutaneous Nomogram Results in Better Prediction of Significant Hyperbilirubinemia in Healthy Term and Near-Term Newborns: A Pilot Study

BACKGROUND:The American Academy of Pediatrics has recommended a systematic assessment before discharge for the risk of severe hyperbilirubinemia. Plotting total serum bilirubin (TSB) or transcutaneous bilirubin (TcB) on a TSB hour-specific nomogram is proposed as a tool for laboratory evaluation.OBJECTIVES:The aim of this study was to compare the predictive characteristics, particularly the incidence of false negative rate (FNR), of the practice of plotting TcB values on the TSB hour-specific risk nomogram versus on transcutaneous nomogram.METHODS:Paired TSB and TcB measurements were conducted on 141 newborns. Risk of developing significant hyperbilirubinemia was defined as infants with bilirubin level ≥ 75% on TSB or ≥ 95% on TcB nomogram. TSB values, plotted on the TSB nomogram of Bhutani et al. [Pediatrics 1999;103:6-14], were used as reference. TcB values were plotted on the TSB nomogram and on the transcutaneous nomograms of Maisels and Kring [Pediatrics 2006;117:1169-1173] and Fouzas et al. [Pediatrics 2010;125:e52-e57].RESULTS:Plotting TcB measurements on a TSB nomogram resulted in a trend towards a higher FNR when compared to Maisels' and Fouzas' nomograms (18.0/1,000 compared to 10.2/1,000 and 8.6/1,000 respectively). Although not statistically significant, plotting TcB on transcutaneous nomogram resulted in better predictive values with the Fouzas' nomogram, having the best sensitivity (90.0%) and specificity (87.79%) as well as the highest positive (35.97%) and negative (99.14%) predictive value.CONCLUSION:Plotting TcB on a TSB nomogram may result in increased rate of FNR and decreased predictive characteristics. The practice of plotting TcB on a TSB nomogram needs further evaluation.