Transcutaneous bilirubin (TcB) was measured with a new bilirubinometer, BiliCheck, in 261 jaundiced infants in the neonatal intensive care unit (NICU) [gestational age (GA) 25–43 wk] (group 1) and in 227 healthy jaundiced term and near-term infants (GA 35–43 wk) (group 2). Imprecision of a single determination of TcB measured on the forehead [TcB(h)], expressed as 1 standard deviation, was 15–18 μmol l−1. No statistically significant difference between intraoperator and interoperator imprecision was found. There was a good correlation between TcB(h) and total serum bilirubin (TSB) in both groups of infants, although TcB(h) was on average lower than TSB. In the NICU infants, TcB(h), other things being equal, was lower in males than in females, and decreased with increasing postnatal age, for the same TSB level. In the infants in both groups who had a GA ≥35 wk, sick infants had a higher TcB(h) than healthy infants for the same TSB level. The differences were statistically significant, but small and of minor clinical significance. Blood haemoglobin concentration, GA and ethnic origin were not found to influence TcB(h), i.e. BiliCheck corrects sufficiently for these factors. In all 488 infants, TcB was measured at four different body sites. Measurements on the forehead and sternum [TcB(s)] correlated well with TSB, while measurements on the knee and foot correlated less well. In the NICU infants TcB(h) predicted TSB statistically significantly better than TcB(s), while in the healthy term and near-term infants TcB(h) and TcB(s) predicted TSB equally well. Therefore, the preferable body site for measurement of TcB under routine conditions is the forehead. By retrospective analysis of the data, a screening model is presented whereby TcB(h) can be used to screen infants who require phototherapy. We found that using screening limits for TcB(h), which are 70% of the currently used phototherapy limits for TSB, 80% of blood samples in healthy term and near-term infants, and 42% of NICU infants with GA ≥32 wk, could be avoided.
Conclusion: BiliCheck is suitable for screening both NICU and healthy newborn infants with jaundice, with regard to the need for phototherapy. The authors recommend using a TcB(h) limit which is 70% of the currently recommended TSB limits for phototherapy, to decide whether TSB needs to be measured.