Assessment of a transcutaneous device in the evaluation of neonatal hyperbilirubinemia in a primarily Hispanic population

Objective. To compare estimates of serum bilirubin as determined by a transcutaneous device (BiliChek [BC]) with laboratory-measured total serum bilirubin (TSB) in a predominately Hispanic population in which a significant number of TSB values greater than or equal to 15 mg/dL was anticipated. Methods. A total of 248 Hispanic and 56 non-Hispanic neonates were studied. Transcutaneous measurements were performed by 1 investigator within 30 minutes of blood sampling for TSB; TSB was determined in a large clinical laboratory using the diazo Jendrassik-Grof with blank method. Agreement between BC and TSB determinations was assessed using Bland-Altman plots and the Bradley-Blackwood test. Interdevice comparisons were made among the BC devices. Predictive indices for TSB >10 mg/dL and >15 mg/dL were determined using various BC cutoff values. Results. TSB was greater than or equal to15 mg/dL in 31% of the Hispanic neonates. BC generally tended to underestimate TSB determinations, and this trend was more pronounced when TSB was >10 mg/dL. Very high sensitivities were observed only when relatively low BC cutoff values were used to predict TSB >10 mg/dL or >15 mg/L. Relatively small numbers of infants had BC values in these low ranges. Conclusions. The tendency of BC to underestimate TSB limits its usefulness in neonates with relatively high TSB. In this population, most infants would have required additional evaluation to ensure that TSB was not >10 mg/dL or >15 mg/dL. It seems that the discrepancy between this study and previous studies of BC is related to our relatively large number of TSB values greater than or equal to 15 mg/dL.