Erythrocyte Alloimmunization and Autoimmunization among Blood Donors and Recipients visiting a Tertiary Care Hospital.

Introduction: The ultimate aim of pretransfusion testing is the acceptable survival of donor red cells in recipient's body and antibody detection plays a critical role in achieving the same. The cornerstone of antibody detection method is detecting an unexpected antibody as against the expected antibodies of ABO blood group system. Autoantibodies can also interfere with the detection of clinically significant alloantibodies.

Aim: To study the frequency of alloantibodies and autoantibodies in the healthy blood donors and patient population visiting our hospital.

Materials And Methods: The Column Agglutination Technology (CAT) was used for ABO RhD blood grouping, Direct Antiglobulin Test (DAT), Autocontrol (AC), Indirect Antiglobulin Test (IAT) and red cell antibody screening and the unexpected reactions in any of these tests were recorded for further evaluation. Ethylene Diamine Tetra Acetic Acid (EDTA) blood samples were used for all these tests for both blood donors and admitted patients. The CAT was exercised for the blood grouping (using ABD-Reverse Diluent cassettes) and antibody screening (using 0.8% Surgiscreen, Ortho Clinical Diagnostics Limited, USA and Low Ionic Strength Saline Ortho BLISS with AHG cassettes) on the automated immunohaematology platform ORTHO AutoVue Innova system (Ortho Clinical Diagnostics Limited, USA).

Results: Among all blood donors (n=6350), seven (0.11%) donors had showed unexpected reaction. Of these, four had positive antibody screen (three having naturally occuring antibodies 2=anti-M, 1=anti-Le and 1=inconclusive) and the other three had positive DAT. Of all the patient samples (n=6136) screened for irregular red cell antibodies, four (0.06%) patients were found to have unexpected reaction revealing one (0.02%) with anti-M antibody and the other three (0.05%) had autoantibodies in their serum.

Conclusion: The combined prevalence for both blood donor and recipient population (n=12,486) was found to be 0.11% at our center. The alloimmunisation among patient population was found to be lower than many other studies worldwide as our hospital does not cater to multitransfused or transfusion dependant patients with haematological disorders and majorly elective surgery patients with no history of previous blood transfusions visit our hospital.