Establishing Blood Group Genotyping to Resolve ABO Discrepancies in Iran

ABO discrepancies are recognized when the reactions obtained in the forward type do not "match" the reactions obtained in the reverse type. Discrepant results are often caused by a variant ABO gene. Molecular analysis is required to confirm the type of subgroups and discrepancy. In this study ABO genotyping was performed on a series of blood donors and patients to determine their definite blood groups. We examined 100 samples with ABO discrepancies from blood donors and patients referred to Tehran Blood Transfusion Center between October 2015 and August 2016. ABO genotyping was performed on all samples with allele specific PCR for differentiation of A, B and O alleles. Exon 6 and 7 of ABO gene were sequenced to confirm the results. The genotyping of donor/patients samples with discrepant results of ABO blood typing consisted of 61 cases of A₂ and A₂B, 3 cases of B 302 and 4 cases of Aw06. Genotyping of 6 samples that had extra antibody in their serum (AB blood group) confirmed the cell type reaction results. 6 samples that had shown a very weak reaction with anti-AB (similar to O blood group) and had no anti-A in their serum were genotyped as O ₁ O ₂. Blood group genotyping laboratory provides an efficient service for evaluation of ABO discrepancies and resolve the problems encountered in serology reactions.