“FREQUENCIES OF ABO, RH, KELL ANTIGENS IN BLOOD DONORS AT A NORTH INDIAN TERTIARY BLOOD CENTER: A CROSS-SECTIONAL STUDY. “

Context: It is important to assess the ethnic distribution of Red Blood Cell (RBC) antigen phenotype frequencies in the population as it helps in establishing a comprehensive donor data bank. It also helps in formulating indigenous cell panels and ensuring the availability of specific antigen negative compatible blood.   Aims: To assess the prevalence of ABO, Rh, and Kell antigens among replacement blood donors from diverse ethnic groups in Northern India.   Settings and Design: This prospective observational cross-sectional study was conducted over a one-year period from November 2022 to October 2023 at a tertiary care hospital of north india.   Methods and Material: 500 random samples were collected from healthy voluntary and replacement blood donors, representing diverse ethnic groups and were phenotyped for A,B, Rh (D,C, E, c, e) and Kell (K) antigens using column agglutination technology glass bead based cassettes. The data was compiled into Microsoft Excel and was then analyzed through IBM SPSS Statistics version 27. Chi-Square (χ²) test was utilized to evaluate the significance of relationships   Results: This study involved phenotyping 500 samples collected from donors of diverse ethnic groups, including Dogras, Non-Gujjar Muslims (NGM), Gujjar Muslims (GM), Sikhs, Kashmiri Pandits (KPs), and Christians. Nearly 35.4% (n= 177) donors were B group,O = 28.2% (n= 141), A = 25.6% (n= 128), and AB = 10.8% (n= 54). On extended phenotyping for Rh antigens, frequency of ‘e’ antigen was 97.6% (n=488),‘D’ antigen 94.6% (n=473), ‘C’ antigen 86.6% (n=433), ‘c’ antigen 62% (n=310) and ‘E’ antigen 19.4% (n=97). It was observed that R1R1 phenotype was highest among Sikhs (43.33%), R1r among Christians (50%), R1R2 among Gujjar Muslims (20.93%), R2r among Kashmiri Pandits (16.66%), R2R2 among Christians (50%),  R0r among Gujjar Muslims (4.65%), rr among Gujjar Muslims (11.62%) and r’r (0.55%) among Dogra population. The overall frequency of the Kell (K) antigen was 2.6%,highest among Gujjar Muslims (4.65%). The prevalence of Kell (K) antigen was higher among 'A' blood group donors (3.9%), followed by the 'AB' group (3.7%), 'O' group (2.83%), and 'B' group (1.12%).   Conclusions: Red cell antigen frequencies across diverse ethnic populations helps in establishing a robust donor database and development of in-house cell panels and fulfils the need of antigen negative compatible blood. Phenotyping aids in diminishing the likelihood of RBC antigen allo-immunization and the related complications. This can further contribute to the development of a rare blood group registry at both regional and national levels.