A2 Subgroups of Blood Group 'A' and 'AB' in Tertiary Care Hospital: A Reflection of their Prevalence in Trivandrum

Introduction The two primary subgroups of A antigen are A1 and A2. About 0.4% of A2 subgroups and 25% of A2B have anti-A1 antibody which agglutinates A1, but not A2 cells. Materials and Method In this study conducted in a major blood bank, group-wise analysis of 750 donors over three months, with special emphasis on the percentage of A2 and A2B individuals was done. Also, identification of A2 and A2B subgroup was done in patients. The chance of occurrence group A2 and A2B patients, transfused with A1 group blood were framed and the percentage of them showing positive ICT were identified. This was done in an attempt to predict the possibility of these A2 subgroups being produced immune anti-A1 antibody to the transfused A1 and A1B red cells. Results Out of the 632 A group donors, A1 antigen were present in 574 (90.8%) and A2 antigen was present in 58 (9.17%) donors. In AB group, 104 were A1B and 14 were A2B. A2 subgroup was found in 9.17 % of A and 13.46% of A2B. Out of 86A and 14AB group blood patients, 6A2 and 2 A2B patients were found and ICT on these patients revealed that 5 A2 and 1 A2B patient tested positive for irregular antibodies. Conclusion Routine detection of A2 subgroup will contribute significantly to the prevention of hemolytic reaction by a natural/acquired anti-A1 antibody and will also prevent the mistaken transfusion of A2 subgroup blood to an O recipient.