Abstract: Objective To analyze a phenomenon in 3 cases of HDN, the false negative of D antigen due to D antigen masking. Methods Blood type and antibody titers of maternal and newborn specimens were detected by blood group serology, and antibody screening and identification were carried out. DAT, free antibody and released antibody tests were performed on the samples of the children, and genotyping was carried out. Results DAT, free antibody and released antibody were positive in 3 neonates. The results of maternal and neonatal antibody screening and identification were anti-D antibody, and the titers were all greater than 512. The blood type test of the child was negative for RhD, and the red blood cells of the child were weakly positive after heat release at 56℃. The gene result of the 3 cases was positive for RhD antigen, and the effect of blood exchange treatment was good. Conclusion The high titer of maternal anti-D antibody can lead to D antigen masking phenomenon, which makes the newborn RhD antigen false negative and further increases HDN. It is necessary to give newborn treatment as soon as possible and accurately detect the newborn blood type.

Key words: RhD fetal neonatal hemolysis, Antigen masking, High potency