Efficacy of transcutaneous bilirubinometry as compared to serum bilirubin in preterm newborn during phototherapy.

Transcutaneous measurement of bilirubin is being used for neonatal jaundice. Its utility during phototherapy in preterm babies is not established. The objective of our study was to assess the efficacy of transcutaneous bilirubin (TcB) measurement in comparison to total serum bilirubin in preterm newborns at admission and during phototherapy at the covered skin area (glabella). It was a prospective observational study and conducted at the neonatal intensive care unit of a tertiary care hospital from January 2017 to January 2019. One hundred eligible preterm neonates were enrolled. Babies who were very sick, with poor peripheral circulation, edematous, having conjugated hyperbilirubinemia, with major congenital malformations, already received phototherapy or exchange transfusion were excluded. Paired total serum bilirubin and transcutaneous bilirubin were measured at admission and 6 h and 24 h during phototherapy. TcB was measured from the area (glabella) covered by an eye protector during phototherapy. The sample for TsB was taken within 10 min of TcB measurement. The mean differences between TsB and TcB values at admission and 6 h and 24 h of phototherapy were - 0.005 (0.353) mg/dl, - 0.350 (0.611) mg/dl, and - 0.592 (0.353) mg/dl, respectively. At admission or before starting of phototherapy, the difference (TsB-TcB) was statistically not significant (p = .125), while the difference in these values was statistically significant at 6 h and 24 h of phototherapy.Conclusion: TcB measurements from the covered skin area in jaundiced preterm infants during phototherapy were not correlated with TsB and cannot be used as an alternate of serum bilirubin testing. What is known • HPLC bilirubin measurement is a gold standard test for bilirubin measurement but impractical for day to day use. Serum total bilirubin is used for clinical testing.. • There is evidence for use of transcutaneous bilirubinometry for assessment of bilirubin in term newborn. What is new • TcB measurements from a covered skin area in jaundiced preterm newborns under phototherapy were not correlated significantly at 6 h and 24 h of phototherapy, but correlated before phototherapy. • TcB cannot be used as an alternate of serum bilirubin testing in preterm infants during phototherapy.