A Study of A1 and A2 Subtypes Among Whole-Blood Donors With Blood Groups A and AB at the Blood Center of a Tertiary Care Institute in Chhattisgarh.

INTRODUCTION: The ABO blood group shows various subtypes due to the heterogeneity of A and B alleles. The frequency of these subtypes varies in different populations. Studies related to the frequency of subtypes of blood groups A and AB are lacking in this region. So, we planned this study to estimate the prevalence of A1  and A2 subtypes among the healthy blood donor population.

MATERIALS AND METHODS: This was a prospective study performed in the blood center of a teaching hospital in the Chhattisgarh state. Healthy whole-blood donors were included in the study after written informed consent. The conventional test tube method was used for performing forward and reverse blood grouping. Testing with anti-A1 and anti-H lectin was performed in blood groups A and AB. Additional tests such as saliva testing for secretor status and adsorption-elution were performed if needed.

RESULTS: Four thousand one hundred twelve donor samples were studied, out of which 1170 showed A antigen. Among 1170 samples, 74.6% were blood group A, and 25.4% were AB. Among blood group A, 92.3% were A1  and 3.3% A2 ,  and the rest were other subtypes, while in AB, it was 85.2% A1 B and 14.8% A2 B. Two cases of anti-A1 antibodies were also noted, which were clinically insignificant.

CONCLUSION: We observed a significantly higher proportion of A2 B than A2 in our study population. We also found a large proportion of Aint in the study participants. Testing with anti-A1 and anti-H lectin is recommended in blood groups A and AB to determine various subtypes and prevent any incompatibility.