Diagnostic Accuracy of Umbilical Cord Bilirubin Measurement in Development of Significant Hyperbilirubinemia in Healthy Neonates

Background: To determine the diagnostic accuracyof umbilical cord blood bilirubin in determining thedevelopment of significant hyperbilirubinemia onthe 3rd day of life in healthy full term newborns,keeping serum bilirubin as a gold standard.Methods: In this cross sectional study babiesdelivered consecutively were taken.Any conditionwhich can aggravate hyperbilirubinemia and anypatient with congenital abnormality were excluded.Cord blood sample was collected from the neonatalend of the umbilical cord after it had been cut andinvestigated for serum total bilirubin (STB).Venous sample was taken on the 3rd day of life andsent for serum total bilirubin. Babies were thendischarged or admitted for treatment depending ontheir serum total bilirubin levels. Mean serum totalbilirubin in cord blood and mean total serumbilirubin on 3rd day of life was calculated. A 2 x 2table was constructed to determine sensitivity,specificity positive and negative predictive values.Results: The mean cord STB was 2.0 mg/dl ± 0.6.Out of the 115 babies, 26% developed significanthyperbilirubinemia requiring phototherapy, onlyone needed exchange transfusion. The resultsshowed that cord blood bilirubin ≥2.5mg/dl had thehigh sensitivity (87%) and specificity (98%) topredict the newborn that would develop significanthyperbilirubinemia. At this level the negativepredictive value was 95%. The diagnostic accuracy ofcord bilirubin 94.8%.Conclusion: A cord blood STB of ≥2.5md/dl ispredictive of significant hyperbilirubinemia on the3rd day of life in healthy neonate