EVALUATION OF TRANSCUTANEOUS BILIRUBIN AS A SCREENING TOOL FOR SIGNIFICANT JAUNDICE IN TERM AND LATE PRETERM NEWBORNS AT THE UNIVERSITY COLLEGE HOSPITAL IBADAN

Abstract

Neonatal jaundice remains a major cause of immediate and long term morbidity in Nigerian
neonates. Early postnatal discharge and late presentation of jaundiced neonates in hospital are
two major factors contributing to this. Transcutaneous bilirubin measurement is non-invasive
and has been validated in developed countries for identification of babies at risk of developing
significant hyperbilirubinaemia prior to discharge. This study sought to evaluate the validity of
transcutaneous bilirubin at 24 and 48 hours of life as a screening tool for the identification of
neonates at risk of developing significant hyperbilirubinaemia.
This was a prospective analytical study of term and late preterm neonates delivered at the
University College Hospital (UCH). Their transcutaneous bilirubin (TcB) was measured over
the forehead and sternum at 24 and 48 hours of life using JM–103 cutaneous jaundice meter.
Paired TcB and total serum bilirubin (TSB) measurements were taken at 48 hours and babies
who developed clinical jaundice had their TcB and TSB measurements monitored till day 7.
The correlation between TcB and TSB measurements was determined by Pearson’s correlation
analysis. Linear regression analysis was used to estimate TSB from TcB. The cut off values of
TcB that predicts the risk of significant hyperbilirubinaemia was determined using the area
under the receiver operating characteristic curve (AUC).
Of the 340 subjects, 286 (84.1%) were term and 54 (15.9%) late preterm, 284 (83.5%)
developed clinical jaundice after 48 hours of life and were followed up and 33 (9.7%) had
significant hyperbilirubinaemia (TSB greater than 13mg/dl). The mean (SD) TcB at 24 and 48
hours were 6.9 (3.1) mg/dl and 9.6 (4.1) mg/dl, 6.8 (3.2) mg/dl and 9.8 (4.3) mg/dl for face and
sternum respectively. The mean (SD) TSB at 48 hours was 5.8 (3.3) mg/dl. Transcutaneous
bilirubin measurement significantly overestimated TSB at all ages with a mean difference
ranging from 3.8 to 4.2 mg/dl at 48 hours. Also, the mean (SD) TcB was significantly higher
from 24 hours in neonates who developed significant hyperbilirubinaemia.
The rate of rise in TcB between 24 and 48 hours was significantly higher in those who
developed significant hyperbilirubinaemia. There was a strong positive linear correlation
between TSB and TcB (face) at 48 hours in all subjects (r = 0.85), term (r = 0.86) and late
preterm (r = 0.73). So also with TcB (sternum) at 48 hours for all subjects (r = 0.85), term (r =
0.86) and late preterm (r = 0.78). The optimal cut off value of TcB at 24 hours that predicted
risk of developing significant hyperbilirubinaemia was 8.4 mg/dl with sensitivity and
specificity of 87.1% and 75.1% respectively for face and 83.9% and 79.0% for sternum. At 48
hours, the cut off was 12.2 mg/dl and 11.3 mg/dl for face and sternum with sensitivity of 80.6%
and 87.1% respectively and specificity of 78.6% and 70.0% respectively. The negative
predictive values of these cut offs ranged from 92.3% to 99.0% for face and sternum in term
and preterm neonates.
Transcutaneous Bilirubin measurements at 24 and 48 hours predicted with high sensitivity and
negative predictive values the likelihood of developing significant hyperbilirubinaemia during
the first week of life. Transcutaneous Bilirubin measurement is recommended for routine
screening of babies before discharge.

EVALUATION OF TRANSCUTANEOUS BILIRUBIN AS A SCREENING TOOL FOR SIGNIFICANT JAUNDICE IN TERM AND LATE PRETERM NEWBORNS AT THE UNIVERSITY COLLEGE HOSPITAL IBADAN