Background Jaundice is a common problem affecting 8–10% of preterm and term newborn babies in the first week of life. Efforts have been made to have non-invasive diagnostic devices available for reliable and quick bedside testing of bilirubin levels in order to avoid painful blood taking and delays due to awaiting results from the laboratory. Several transcutaneous devices can estimate bilirubin levels in the newborn and have mostly been tested in term infants. The correlation co-efficient between transcutaneous and laboratory values have been reported to be 0.46 to 0.89 depending on the device. The device cannot be used after phototherapy has started as bilirubin isomeres are produced. Thus a non-invasive device which can measure after the start of phototherapy in preterm and term infants is warranted.
Objective To establish whether the non-invasive white light spectroscopic (WLS) device (Bilispect (R), MBR Optical Systems, Wuppertal, Germany) can measure bilirubin in the skin of preterm and term jaundiced babies before and after phototherapy.
Methods Prospective single centre study of preterm and term infants who had their bilirubin levels taken for clinical reason in a convenience cohort sample. Best measurement site on skin was determined by comparing WLS measurements at 4 Kramer zones (forehead, sternum, forearm and foot) in 9 infants. Forearm fared best. Prospective WLS measurements were taken within 15 min of the blood test at the forearm of the baby. Statistical comparison was performed by Bland-Altman method. Intra- and inter-observer variability were calculated by using repeated measurements and two observers. The ethics committee issued a favourable opinion and informed consent was obtained from parents.
Results Comparisons were obtained in 47 preterm and term infants (range 24–40 weeks gestation, birth weight 564–4220 g), who had 51 paired bilirubin samples done. Ten were taken after phototherapy had been started. Correlation coefficients for samples taken after phototherapy was 0.87 and 0.9 without phototherapy. Intra-observer and inter-observer variability were 0.67 and 0.69 respectively.
Conclusions The results show a good correlation between the laboratory and non-invasive bilirubin values. The WLS seems to be a suitable method for estimating bilirubin levels after phototherapy has started and particularly in preterm infants. Further field studies re required in order to obtain nomograms for this device.