Predicting neonatal hyperbilirubinemia using first day serum bilirubin levels

Abstract

To determine the first day total serum bilirubin (TSB) value which will predict with reasonable accuracy, neonates likely to develop subsequent significant hyperbilirubinemia. Serum bilirubin was estimated for all enrolled cases within 18 to 30 hr of life by microcapillary. The babies were then followed up clinically by 2 observers for the appearance and progression of jaundice every 12 hr till discharge and then daily upto fifth day of life. TSB estimation was repeated if the clinical assessment of jaundice was more than 10 mg/dl by any observer using Kramers Rule. Hyerbilirubinemia was defined as TSB level > or =12 mg/dl between 24 to 48 hr of life > or =15 mg/dl between 48 to 72 hr of life and 17 mg/dl beyond 72 hours of life. A total of 200 neonates were enrolled in the study. Of these, 24 neonates (i.e., 12%) developed hyperbilirubinemia. The mean first day TSB value in the neonates who subsequently developed hyperbilirubinemia was 7.716 mg/dl as compared to a value of 5.154 mg/dl in those who did not. The difference was significant (p=0.000). Using Receiver operating characteristic (ROC) curve analysis, a value of 6.4 mg/dl (first day TSB) was determined to have the best predictive ability for subsequent hyperbilirubinemia with a sensitivity of 87.5%, specificity of 80.11%, positive predictive value of 37.5% and a negative predictive value of 97.92%. First day TSB estimation can serve as a reliable screening test for neonates at risk for subsequent hyperbilirubinemia. Neonates with the first day TSB level of less than 6.4 mg/dl have minimum risk of subsequent hyperbilirubinemia.