Background and aim We have previously shown that using Transcutaneous bilirubin (TCB) values that are 90% of the age specific SBvalue (SBPh) for phototherapy can markedly reduce the need for invasive serum bilirubin (SB) in Day 1–3 inpatient babies. This study aims to determine if the same principle can be applied in older babies in the outpatient setting.
Methods Three to 14 day olds with jaundice at an outpatient care centre in Singapore and needing a SB measurementwere enrolled after obtaining written informed consent. Their TCB level was determined with a commercial bilirubinometer. Correlations and Bias was determined. Using ROC curves, the TCB values that identified the need for an SB were determined.
Results 1072 paired SB and TCB values were obtained from a Chinese (39%), Malay (35%), Indian (14%) and Others (12%) cohort. Spearman’s correlation coefficientsby age groups ranged from 0.882(2–5 days) to 0.95 (> 14 days). The mean bias (SD) was -8(23.2) and the limits of agreement were -54.4 to 38.4 from the Bland Altman analysis. TCB values that were 90% of the SBPh yielded accuracy and sensitivity rates (%) of 90 and 100 in the < 96 h age group and 96 and 83 in the older group. The efficiency (% of SB avoided) was 89 and 96% respectively in the two age groups.
Conclusion TCB measurements that are a predetermined fraction of the SBPh can efficiently reduce SB determinations in the newborn period. The fraction is influenced also by the operational context.