Predictive Ability of Direct Antibody Testing in Infants Born to Mothers with Rh(D) and Other Minor Red Blood Cell Antibodies

Objective Hemolytic disease of the newborn (HDN) most commonly occurs in neonates whose mothers carry nonpassively acquired antibodies directed against red blood cell (RBC) antigens. Because affected neonates may develop severe hyperbilirubinemia, early identification of at-risk neonates is critically important. We hypothesized that use of the direct antibody test (DAT) would be of high predictive value in identifying those neonates most likely to meet treatment criteria for hyperbilirubinemia. Study Design We performed a retrospective chart review of all mother-infant pairs in which RBC antibodies were detected on routine prenatal screening during the current pregnancy (2011-2013). We then compared DAT results of neonates who eventually met the treatment criteria for hyperbilirubinemia with those who did not. Main Results Fifty-sixty neonates were born to mothers with clinically significant antibodies. The sensitivity and specificity of a positive DAT result for meeting the treatment criteria were 87.5 and 93.3%, respectively. The positive and negative predictive values were 77.8 and 96.6%, respectively. Conclusion The result of a DAT, obtained in neonates of mothers with clinically relevant alloantibodies, is a specific marker with good positive predictive value for identifying those who are most likely to meet the treatment criteria for hyperbilirubinemia.