The value of first-day bilirubin measurement in predicting the development of significant hyperbilirubinemia in healthy term newborns

Objective. The recognition, follow-up, and early treatment of neonatal jaundice has become more difficult, since the earlier discharge of newborns from hospitals has become common practice. This prospective study was undertaken to identify the newborns at risk for developing significant hyperbilirubinemia later during the first days of life by measuring the serum bilirubin levels of the first 5 days of life to determine the critical predictive serum bilirubin value on the first day of life. Methodology. A total of 498 healthy term newborns were followed with daily serum total bilirubin measurements for the first 5 days of life, and cases with serum bilirubin levels of greater than or equal to 17 mg/dL after 24 hours of life were defined to have significant hyperbilirubinemia. Results. No newborns had a serum total bilirubin level of greater than or equal to 17 mg/dL in the first 72 hours of life. Sixty of 498 cases (12.05%) had significant hyperbilirubinemia after 72 hours of life, and these cases had significantly higher bilirubin levels than those who did not develop significant hyperbilirubinemia on each of the first 5 days' measurements. Of the 206 newborns who had a serum bilirubin level of greater than or equal to 6 mg/dL in the first 24 hours, 54 (26.21%) developed significant hyperbilirubinemia, whereas only 6 of the 292 newborns (2.05%) who had a serum bilirubin level of <6 mg/dL on the first day developed significant hyperbilirubinemia. A mean serum bilirubin level of greater than or equal to 6 mg/dL on the first day had the highest sensitivity (90%). At this critical serum bilirubin value, the negative predictive value was very high (97.9%) and the positive predictive value was fairly low (26.2%). Furthermore, because no cases with a serum bilirubin level of <6 mg/dL in the first 24 hours of life required a subsequent phototherapy treatment and because all of those infants requiring a phototherapy treatment with serum bilirubin levels of greater than or equal to 20 mg/dL were just among the cases whose first-day bilirubin levels were greater than or equal to 6 mg/dL, the critical bilirubin level of 6 mg/dL on the first day made it possible, with the highest (100%) sensitivity and negative predictive value, to definitely predict all of the infants who would have a bilirubin level of >20 mg/dL, requiring a phototherapy treatment later during the first days of life. Conclusions. A serum bilirubin measurement and the use of the critical bilirubin level of 6 mg/dL in the first 24 hours of life will predict nearly all of the term newborns who will have significant hyperbilirubinemia and will determine all those who will require a phototherapy treatment later during the first days of life.