Distribution of ABO and Rhesus Blood Group Phenotypes Among Blood Donors at Bahir Dar Blood Bank, Amhara, Northwest Ethiopia: A Retrospective Cross-Sectional Study.

Background: Among the blood group antigens identified, ABO and Rhesus are the most important in transfusion medicine. ABO blood group antigens are the most immunogenic followed by Rhesus (D antigen). These blood groups' frequency distribution varies among different regions and races of the world. This study aimed to identifying the frequency distribution of ABO blood group and rhesus factors among blood donors in Ethiopia.

Methods And Materials: Aretrospective cross-sectional study was conducted from September 12/2019 to March 18/2021 at Bahir Dar blood bank service. After getting a permission letter from the blood bank, data were collected from the blood bank donor data registration system, and descriptive statistical results were presented in number (frequency) and percentage. A Chi-square test was used to show the difference in the frequency distribution of ABO and Rh blood groups among sex and blood donation site.

Results: From 40,053 blood donors, 67.7% were males and younger donors (within the age range of 18-24 years) account for 63.7%. All donations were from voluntary non-remunerated blood donors. The most common blood group was blood group O (41.5%) followed by A (29.8), B (23.2%), and AB (5.5%). Considering ABO and Rh blood group altogether blood group O positive with 37.9% was the predominant blood group followed by A positive (27.2%), B positive (21.4%), AB positive (5%), O negative (3.6%), A negative (2.6%), B negative (1.8%), and AB negative (0.4%). The majority of study participants were 91.5% Rh (D) positive.

Conclusion: This study showed that blood group O was the predominant followed by A, B, and AB and most of the blood donors' blood groups were Rh-positive (91.5%). About 68.9% of the total donations were from the first time donor.