Introduction. Blood transfusion is a strong practice in traumatology, internal medicine, haematology, obstetrics and transplantation, which demands safety of haemotransfusion with estimating the red blood cell group antigens in donor and recipient blood. Routine immunotyping techniques usually provide for an antigen identification to weak subgroups, albeit with certain inherent limitations of serology tests that can be overcome in a genotyping approach.Aim — performance assessment of serology and genotyping methods in the ABO, RH and KEL blood group identification.Materials and methods. A total of 55,489 donor and 1,898 patient blood samples have been analysed. Ambiguous cases of chimerism, panagglutination and inconsistent results were tackled with genotyping. Serology tests were performed with gel cards. Whole blood DNA extraction was performed with Qiagen chemistry. Allele-specific PCR was used for the erythrocyte ABO, RH and KEL antigen genotyping with BAG Diagnostics commercial kits and a 2% agarose gel product detection. Sanger sequencing was used to complement genotyping.Results. A combined use of serology tests and genotyping allowed a successful erythrocyte antigen-based blood group and Rh-status assignment in 26 donors and patients with ambiguous blood typing.Conclusion. Genotyping coupled with serologic methods can be advised in a hampered blood group identification.