ABO Blood Group and Rhesus (Rh) Antigen Distribution Among Blood Donors in the North Al Sharqiyah Governorate in Oman

Background The distribution of ABO and Rhesus (Rh) blood group antigens varies across different geographical and ethnic populations. Understanding these indigenous variations is crucial for effective blood bank management, ensuring safe transfusion practices, and preventing alloimmunization, particularly in multi-transfused cases. While national data for Oman exists, specific data for the North Al Sharqiyah Governorate has been lacking. This study aimed to determine the distribution of ABO and the five major Rh antigens (D, C, c, E, e) among volunteer blood donors in the North Al Sharqiyah Governorate of Oman and to compare these frequencies with established national data to identify significant local variations. Methods This is a retrospective, cross-sectional study conducted at the laboratory department in Ibra Hospital over a 35-month period (December 2017 - October 2020). Data from 1,433 eligible volunteer blood donors were analyzed. ABO and RhD typing, along with Rh phenotyping for C, c, E, and e antigens, were performed using standardized serological gel card techniques. Frequencies were calculated and compared to published national Omani data using the chi-squared test. Results The most common blood group was O positive (55.1%), followed by A positive (26.6%). Overall, 88.1% of donors were RhD positive and 11.9% were RhD negative. The most prevalent Rh antigen was 'e' (97.1%), and the least common was 'E' (19.9%). Significant regional differences were observed when compared to national data: a higher frequency of group A (29.3% vs. 18%; chi-square= 17.605, <i>p</i> value < 0.0001) and a lower frequency of group B (6.2% vs. 22.9%; chi-square= 89.47, <i>p</i> value < 0.0001). Notably, the R1R2 (DCe/DcE) phenotype was significantly less common in our cohort (9.0%) compared to the general Omani population (18.3%; chi-square = 24.54, <i>p</i> value < 0.0001). The R⁰r (Dce/ce) phenotype prevalence is higher among study donors than the Oman population (9.07 vs. 5.7; chi-square = 4.012, <i>p</i>-value = 0.0452). Conclusion This study reveals a distinct ABO and Rh phenotype distribution among blood donors in the North Al Sharqiyah Governorate compared to the national profile. The findings highlight a regional need for targeted blood donor recruitment, particularly for group B, and underscore the importance of local epidemiological data for optimizing blood inventory and enhancing transfusion safety.