Distribution of ABO and Rh Blood Groups and Allele Frequencies in the Bhutanese Population: A Retrospective...

The prevalence of ABO and Rh blood groups varies among different populations, influencing blood bank management and transfusion safety. This retrospective cross-sectional study is aimed at analyzing the distribution of ABO and Rh(D) blood groups and their allele frequencies in the Bhutanese population.

Retrospective data were collected from five geographically representative hospitals in Bhutan between 2019 and 2023, including three referral hospitals and two district hospitals. The study sample comprised 40,249 individuals, including blood donors, mothers at antenatal clinics, and patients undergoing medical screening during the period January 2019 to December 2023. ABO and Rh blood groups were determined by slide and/or tube agglutination tests in each hospital's laboratory. Allele frequencies were calculated using Hardy-Weinberg equilibrium principles.

In this retrospective cross-sectional study of 40,249 individuals from five hospitals across Bhutan, the most common ABO blood group observed was O (n = 13,993; frequency = 0.347), followed by A (n = 13,015; 0.323), B (n = 9742; 0.242), and AB (n = 3499; 0.086). Rh(D)-positive individuals accounted for the vast majority (n = 40,105; 0.9964), while Rh(D) negative was rare (n = 144; 0.0035). The allele frequencies were 0.229 for I^A, 0.178 for I^B, and 0.589 for I^O in the ABO system and 0.940 for I^D and 0.059 for I^d in the Rh(D) system.

This study highlights the predominance of blood group O and Rh(D) positivity in the Bhutanese population. The allele distribution shows a higher frequency of the I^O and I^D alleles, indicating genetic homogeneity in blood group distribution. These findings provide essential baseline data for transfusion medicine, population genetics, and future public health planning.