The Distribution of Kell Blood Group Antigens and Phenotypes (K and K) Among Saudi Blood Donors of King Abdulaziz Medical City – Western Region: A Cross-Sectional Study

Hiam O Mulla1– 3 1Clinical Laboratory Sciences Department, College of Applied Medical Sciences, King Saud bin Abdulaziz University for Health Sciences (KSAU-HS), Jeddah, Saudi Arabia; 2King Abdullah International Medical Research Center (KAIMRC), Jeddah, Saudi Arabia; 3Ministry of the National Guard - Health Affairs (NGHA), Jeddah, Saudi ArabiaCorrespondence: Hiam O Mulla, Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud bin Abdulaziz University for Health Sciences (KSAU-HS), P.O. Box 9515, Jeddah, 21423, Saudi Arabia, Tel +966-12-224-6666, Email [email protected]: The Kell (KEL) blood group system is one of the most clinically significant red blood cell antigens due to the K antigen’s high immunogenicity and involvement in transfusion reactions as well as hemolytic disease of the fetus and newborn (HDFN). This study aims to assess the prevalence of K (KEL1) and k (KEL2) antigens, along with their associated phenotypes, among Saudi blood donors at King Abdulaziz Medical City (KAMC), Jeddah, and to compare findings with regional data in Saudi Arabia.Materials and Methods: This cross-sectional study included 19,769 Saudi blood donors at KAMC-Jeddah. Using standard immunohematological techniques, donor samples were screened for K and k antigens. Antigen and phenotype frequencies were calculated and compared with published Saudi studies. Statistical analysis was performed to assess differences in antigen and phenotype prevalence between Saudi populations.Results: The K antigen was detected in 13.93% of donors, whereas 98.92% expressed the k antigen. The most common KEL phenotype was K–k+, accounting for 86.07% of the population, followed by K+k+ (12.85%) and K+k– (1.07%). The K–k– phenotype was found to be exceedingly rare at 0.005%. Comparative analysis demonstrated statistically significant differences in K antigen prevalence between the current cohort and donor populations from Central (KAMC-Riyadh) and Southwestern (Jazan) regions, whereas no notable variations were observed when compared with Makkah and Jeddah within the Western region. The k antigen remained consistently prevalent across all regions. Notably, this study represents one of the largest cohorts reported in Saudi Arabia and identifies a rare K–k– phenotype within the donor population.Conclusion: This study provides a comprehensive assessment of Kell antigen and phenotypic distribution among Saudi blood donors. By reinforcing regional variation as well as the predominance of the k antigen, the findings offer valuable baseline information to support transfusion practices, particularly for transfusion-dependent populations.Keywords: KEL, KEL1, KEL2, kell, Saudi Arabia