ABO and Rh (D) group distribution and gene frequency; the first multicentric study in India

BACKGROUND AND OBJECTIVES: The study was undertaken with the objective to provide data on the ABO and Rh(D) blood group distribution and gene frequency across India. MATERIALS AND METHODS: A total of 10,000 healthy blood donors donating in blood banks situated in five different geographical regions of the country (North, South, East and Center) were included in the study. ABO and Rh (D) grouping was performed on all these samples. Data on the frequency of ABO and Rh(D) blood groups was reported in simple numbers and percentages. RESULTS: The study showed that O was the most common blood group (37.12%) in the country closely followed by B at 32.26%, followed by A at 22.88% while AB was the least prevalent group at 7.74%. 94.61% of the donor population was Rh positive and the rest were Rh negative. Regional variations were observed in the distribution. Using the maximum likelihood method, the frequencies of the I(A), I(B) and I(O) alleles were calculated and tested according to the Hardy Weinberg law of Equilibrium. The calculated gene frequencies are 0.1653 for I(A) (p), 0.2254 for I(B) (q) and 0.6093 for I(O) (r). In Indian Population, O (r) records the highest value followed by B (q) and A (p); O > B > A. CONCLUSION: The study provides information about the relative distribution of various alleles in the Indian population both on a pan-India basis as well as region-wise. This vital information may be helpful in planning for future health challenges, particularly planning with regards to blood transfusion services.