# 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

## TL;DR

This study examines the prevalence of A1 and A2 subtypes in blood donors with A and AB blood groups in Chhattisgarh, India.

## Contribution

The study provides new data on ABO blood group subtype frequencies in a previously unstudied regional population.

## Key findings

- A1 was the most common subtype in blood group A (92.3%) and A1B in AB (85.2%).
- A2B was more prevalent than A2 in AB blood group donors (14.8% vs. 3.3%).
- Two cases of anti-A1 antibodies were found but were clinically insignificant.

## Abstract

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% A1B and 14.8% A2B. Two cases of anti-A1 antibodies were also noted, which were clinically insignificant.

Conclusion: We observed a significantly higher proportion of A2B 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.