ABO Hemolytic Disease Leading to Hyperbilirubinemia in Term Newborns: Value of Immunohematological Tests

ABO hemolytic disease of the newborn is most common cause of neonatal jaundice; previous studies have shown a poor correlation between serologic tests and clinical course in affected infants. The aim of this study was to identify the value of direct and indirect Coombs’ immunohematological tests, to identify the incidence of hemolytic disease in newborns (ABO-HDN). This two-year retrospective study of 1800 jaundiced term-neonates studied 355 cases due to ABO incompatibility divided into two groups: with and without hemolytic disease. Relation of laboratory parameters and immunohematological tests to severity of disease were studied. We did not analyze the maternal antibody titer or elusion test, and this was a limitation of the study. In this study, 355 (19.7%) of all jaundiced newborn infants were ABO incompatibles; 98 (27.6%) of the newborns who had ABO incompatibility showed ABO-HDN (5.4% of total icteric patients). The positive direct antiglobulin (direct Coombs’ test) and indirect antiglobulin (indirect Coombs’ test) were diagnostic in 18.2% and 25.5% respectively in affected infants. The overall prevalence of immunohematological tests associated with ABO-HDN was 43.7%. There was significant correlation between positive antiglobulin tests and severity of jaundice (P=0.000); also there was a significant difference between indirect and direct Coombs’ test and severity of jaundice (P= 0.002). The antiglobulin tests, namely the indirect Coombs’ (IC) test and direct Coombs’ (DC) test are very useful to detect the newborns liable to serious jaundice.