Distribution of ABO, Rhesus, and Extended Blood Group Phenotypes Among Voluntary Blood Donors at the National Blood Transfusion Service, Owerri: A Gender, Age, Genotype and Phenotype-Based Analysis

Blood transfusion services rely on both the availability of blood and a thorough knowledge of the distribution of blood group antigens in the donor community. Although transfusion compatibility testing is based on the ABO and Rhesus (Rh) blood group systems, antibodies to non-ABO antigens like Kell, Duffy, Kidd, and MNS are becoming more widely acknowledged as significant contributors to transfusion reactions, especially in patients who need repeated transfusions. The purpose of this study was to determine the relationships between haemoglobin genotype, age, and gender as well as the distribution of ABO, Rh(D), and specific extended blood group phenotypes among volunteer blood donors at the National Blood Transfusion Service (NBTS), Owerri, Nigeria. Among 1,000 willing blood donors, a descriptive cross-sectional study was carried out (300 females and 700 males). Standard serological methods were used to determine the ABO and Rh(D) grouping. Using certain commercial antisera, extended blood group phenotyping (Kell, Duffy, Kidd, and MNS systems) was carried out. Cellulose acetate electrophoresis was used to establish the haemoglobin genotype. Descriptive statistics and chi-square (χ²) tests were used to analyse the data in order to evaluate the relationships between the categorical variables. P-values less than 0.05 were regarded as statistically significant. The most common blood group was O (71.0%), which was followed by A (13.8%), B (12.4%), and AB (2.8%). 87.2% of donors tested positive for Rh(D). The main donor categories were men and those between the ages of 26 and 35. Of the donors, 71.9% had haemoglobin genotype AA and 28.1% had AS; no SS genotype was found. There was no significant correlation between gender and the distribution of ABO blood groups (p > 0.05), but chi-square analysis showed a significant correlation between gender and the frequency of blood donations (p < 0.001). Extended blood group phenotypic distributions were in line with trends observed in people in sub-Saharan Africa. Blood group O and Rh(D)-positive donors make up the majority at NBTS Owerri, which is consistent with regional and national trends. It is crucial to integrate extended phenotyping into standard transfusion procedures in order to improve patient safety and lower the danger of alloimmunisation, as evidenced by the reported frequencies of clinically important extended blood group antigens.