Background: The blocking of D antigen sites of RBC membrane of the fetus by the passively transferred IgG anti-D in cases of Hemolytic Disease of fetus and new born (HDFN) is called blocked- D phenomenon. The coating of maternal IgG type of anti-D prevents the agglutination of the Rh-(D) antigen positive red blood cells (RBC) by the IgM D-antigen typing reagents. We are reporting two cases of Rh-(D) HDFN which were falsely typed as Rh (D) antigen negative with routine typing reagents and had multiple allo-antibodies in the maternal serum. Aims: To rule out HDFN and to confirm the Rh-(D) status of baby, to detect the presence of other allo-antibodies in the maternal serum that can complicate future transfusions in mother. Materials: After routine blood grouping, sample of baby was subjected to adsorption-elution studies and maternal serum was used for antibody screening and identification Results: In both the cases, blocked-D phenomenon got detected and there were multiple anti-rhesus antibodies other than anti-D in the maternal serum. Conclusion: Antibody identification in antenatal women is important in the case management of HDFN to protect future pregnancies and to avoid the risk of mismatched transfusions.

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