Neonatal ABO incompatibility, influence of blood group, and coomb's test on outcome

Background: Better understanding of the clinical characteristics of ABO hemolytic disease in neonates helps optimize care. Objective: To assess the morbidity associated with ABO incompatibility. Materials and Methods: Neonates with blood groups A or B born to mothers with blood group O were studied. Need for phototherapy (PT), intensive PT, intravenous immunoglobulin (IVIG) therapy, and packed red blood cell (PRBC) transfusions was studied. Results: The O–A group accounted for 57.2% and the O–B group 42.8%. Three-hundred and seventy-nine (46%) were Direct Coomb's test (DCT) positive. Need for PT and intensive PT was significantly higher in DCT-positive infants compared to DCT-negative infants (P < 0.001). DCT-positive infants required more PRBC transfusions (5.3% vs. 0.9%, P < 0.001) and IVIG therapy (6% vs. 0.2%, P < 0.001) compared to DCT-negative infants. Sixty percent of the blood group B infants were DCT positive compared to 35% of blood group A infants (P < 0.001). Need for PT (62% vs. 39%, P < 0.001), intensive PT (17% vs. 4%, P < 0.001), and IVIG therapy (5.4% vs. 0.8%, P < 0.001) was higher in infants with blood group B. TcB measured at median age of 12 h was predictive of the need for PT (area under the receiver operator characteristic [AUROC] =0.867) and intensive PT (AUROC = 0.917). The maximum reticulocyte percentage was predictive for both the need for IVIG therapy (AUROC = 0.978) and PRBC transfusion (AUROC = 0.863). Conclusions: DCT-positive infants and infants with blood group B suffered significantly higher adverse outcomes. TcB measured at 12 h is predictive of the need for PT and intensive PT. Maximum reticulocytes count is predictive of the severity of ABO incompatibility as evidenced by the need for PRBC transfusions and IVIG therapy.