A case report on incidentally detected A2B blood group

Abstract

The two primary subgroup of AB is A1B and A2B. A2B is extremely rare. The differentiation between A1B and A2B is based on the reactivity of A1 cells with anti- A1 lectin. Subgroups can result from inheritance of rare alleles at ABO locus and can cause discrepancy but rarely cause haemolytic transfusion reaction. Most of the subgroups are found incidentally during a pre transfusion testing or pregnancy follow up. Here we report an incidental case of A2B in a 28-year female. The case report highlights the need to be aware of such uncommon and rare blood groups. It also emphasizes on the need to do both forward and reverse grouping routinely.