The benefit of the direct antiglobulin test using gel technique in ABO hemolytic disease of the newborn.

The direct antiglobulin test (DAT) using the gel technique was included in the investigation of infants with hyperbilirubinemia in the first week of life. Twelve cases were preterm and 48 cases were full term infants. The patients were divided into 2 groups: the study group comprised 22 cases of blood group A or B infants born to blood group O mothers; the control group comprised 38 cases of ABO blood groups compatible with those of their mothers. The mean +/- SD (39 +/- 26 hours) of the age at the onset of hyperbilirubinemia induced by ABO hemolytic disease of the newborn (HDN) was significantly earlier than that due to other causes. The positive rate of DAT in the ABO incompatible group was similar by both the conventional technique and the gel technique, 54.5% and 50% respectively. However, the scores by the gel technique were higher than those of the conventional technique. The gel technique is simple, reliable, involves less technical error and requires a small amount of blood sample. The grading system is clear-cut, especially grade 1 + or weak positive as compared to the conventional technique which requires examination under a microscope. Therefore, the DAT using the gel technique is beneficial to the diagnosis of ABO HDN. It should be included in the investigation of infants with hyperbilirubinemia especially in case of suspected ABO HDN.