Characteristics of Bilirubin According to the Results of the Direct Antiglobulin Test and Its Impact in Hemolytic Disease of the Newborn.

Background: Hyperbilirubinemia, which is a sign of hemolytic disease of the newborn (HDN), can irreversibly damage the central nervous system.

Objectives: To determine the etiology of HDN in affected patients and characterize the changing pattern of bilirubin using direct antiglobulin testing (DAT).

Methods: We collected clinical data from newborns who underwent perinatal DAT and from their mothers, between August 2008 and July 2017.

Results: Among 303 neonates, 37 (12.2%) showed positive DAT results. The positive predictive values (PPVs) and negative predictive values (NPVs) based on DAT results were 75.7% and 28.9%, respectively, for starting phototherapy. Bilirubin levels increased more rapidly in the DAT-positive group, compared with the DAT-negative group. The initial bilirubin level differed significantly according to the etiology of hyperbilirubinemia. Further, neonates with anti-D showed higher delta bilirubin per day than neonates with other antibodies.

Conclusion: Our results may help to determine the measurement period for bilirubin according to DAT results and etiology.