Prevalence and Specificity of Red Blood Cell Alloantibodies in Patients in a Tertiary Care Center in Meghalaya, India.

Introduction Red blood cell (RBC) alloimmunization complicates transfusion therapy by making compatible units scarce and increasing the likelihood of hemolytic transfusion reactions, particularly in multi-transfused or sensitized patients. Data from northeastern India remain scarce. This study aims to evaluate the prevalence and specificity of RBC alloantibodies and their clinical associations at a tertiary care center in Meghalaya. Methods We conducted a retrospective, cross-sectional review in the Department of Transfusion Medicine and Blood Centre, North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences, Shillong. From March 2021 to February 2024, we screened every patient with an RBC transfusion request using an antibody screening cell panel and, when necessary, performed antibody identification. We retrieved clinical and transfusion histories from laboratory records and used chi-square tests to examine associations with alloantibody formation. Results Although the overall frequency of alloantibody development was low, certain patterns emerged, most notably higher prevalence in women and transfusion-dependent patients. Women and patients with prior transfusions developed alloantibodies more often than their counterparts. Anti-E, the most common antibody, dominated the Rhesus system findings, and antibodies in the Kidd system were also frequent. Antenatal patients formed the largest subgroup with alloantibodies. Conclusions Routine antibody screening and precise identification should remain central to pre-transfusion testing, particularly for transfusion-dependent individuals and pregnant patients. Our region-specific data support targeted antigen-matching strategies and reinforce the need for robust transfusion policies to enhance patient safety and optimize blood-product use.