Interscapular site for transcutaneous bilirubin measurement in preterm infants: a better and safer screening site

Abstract

To prevent bilirubin induced brain injury in the newborn, repeated blood withdrawals are necessary to ascertain bilirubin levels and institute care. Noninvasive, painless and bloodless screening using transcutaneous bilirubinometry is the standard of care for term and near term neonates but there is still debate about its use with preterm neonates. The aims of this study were to determine how transcutaneous bilirubin (TcB) level measured from the interscapular site related to total serum bilirubin (TSB) level and to compare performance of TcB from the forehead, sternum and interscapular sites in identifying preterm neonates in need of phototherapy. This was a cross sectional study conducted at Groote Schuur level III neonatal unit. Over a 5-month period 122 consecutive preterm neonates <35 weeks gestational age were enrolled. TcBs were measured over the forehead, sternum and interscapular area. Pearson's correlation coefficients and differences between TSB and TcBs were computed. P-value <0.05 was considered significant. The median gestational age of the study participants was 31 weeks (range: 24 to 34 weeks), the median TSB level was 81.5 μmol l(-1) (range: 25 to 229 μmol l(-1)) and 45% had a TSB at the phototherapy threshold. The correlation coefficients for TcBs ranged from 0.859 to 0.929 (P<0.001). The difference between TSB and TcBs ranged from -86 to +51 μmol l(-1). With respect to initiating phototherapy, the interscapular site had the highest sensitivity of 94% and lowest false negative rate of 6%. Using transcutaneous bilirubinometry, the interscapular site is superior and safer for screening preterm neonates.