Am Fam Physician. 2005;71(5):976-978
Transcutaneous bilirubin (TcB) measurements are desirable because of the frequency with which total serum bilirubin (TSB) levels are measured in newborns. However, TcB machines have been limited by the need to convert a bilirubin index using individual hospital data and the machines’ poor performance in children with darker skin. Maisels and colleagues evaluated a meter that may be more convenient to use and more accurate in dark-skinned newborns.
TcB measurements were obtained using the Minolta/Hill-Rom Air Shields Transcutaneous Jaundice Meter JM-103. These measurements were compared with TSB levels of 849 newborns of at least 35 weeks’ gestation with an indication for bilirubin testing. Nearly two thirds of the infants were white, nearly one third were black, and the others were Asian-American, Middle Eastern, Hispanic, and Easstern Indian/Pakistani. TcB and TSB measurements were obtained within one hour of each other.
TSB levels ranged from 1.1 to 20.8 mg per dL (19 to 356 μmol per L), with 3.3 percent being greater than 15 mg per dL (257 μmol per L) and 21 percent greater than 10 mg per dL (171 μmol per L). TcB measurements differed from TSB values by 3 mg per dL (51 μmol per L) or more in 2 percent of white infants, 17.4 percent of black infants, and 3.2 percent of the remaining infants. In the black infants, the TcB measurement was invariably higher than the TSB measurement.
In this study, TcB measurements correlated well with TSB levels, particularly in white infants. The meter tended to overestimate bilirubin levels in black infants, which required more frequent follow-up. Taking measurements with the TcB meter was fast and convenient, but use of the meter by untrained personnel may reduce accuracy. The meter cannot be used in infants receiving phototherapy.