Reliability of transcutaneous bilirubinometry from shielded skin in neonates receiving phototherapy: a prospective cohort study.

Objective: To determine the agreement between transcutaneous bilirubin (TcB) measured from shielded skin and serum total bilirubin (STB) in infants (34 to 41 weeks of gestation) with hyperbilirubinemia receiving phototherapy (PT).

Study Design: In this prospective cohort study, we shielded a small area of skin on sternum using a commercial photo-opaque patch (BilEclipseTM, Philips Respironics, Murrysville, PA, USA). The TcB from the shielded skin (TcBs) and STB were measured at four time points-before initiation, 12 and 24 h during and once after (12 h) cessation of PT. TcB was measured using multiwavelength transcutaneous bilirubinometer (BiliChek, Philips Children's Medical Ventures, Monroeville, PA, USA). The STB was measured in triplicate by spectrophotometry (Apel BR 5100, APEL, Japan). Bland and Altman plots were drawn to determine agreement between the TcBs and STB.

Results: The gestation and birth weight of enrolled neonates were 37.0 (1.0) weeks and 2750 (458) g, respectively. The age at initiation and duration of PT were 75 (27 to 312) and 25.3 (4.4) h, respectively. Bland and Altman plot showed poor agreement between TcBs and STB at all time points. The gradient (median, range) between TcBs and STB at 0, 12, 24 h and 12 h after cessation of PT were -0.2 (-4.9 to 3.5), 1.4 (-4.7 to 4.0), 1.5 (-3.8 to 9.4) and 2 (-2.9 to 5.8) mg dl. The proportions of TcBs values outside ±1.5 mg dl of STB ranged from 47 to 64% at four time points.

Conclusion: TcBs does not appear to be reliable for estimating serum bilirubin in late preterm and term neonates receiving PT.