Introduction: Blood groups are inherited biological characteristics that do not change throughout life in healthy people. Blood groups represent antigens found on the surface of red blood cells. Kell blood group system consists of 31 antigens. Kell antigen (K) is present in 0.2% of the population (the rare blood group). Cellano antigen is present in more than 99% (the high-frequency antigen). These antigens have a distinct ability to cause an immune response in the people after blood transfusion or pregnancy who, otherwise, did not have them before.
Case report: This paper presents a blood donor with a rare blood group, who was found to have an irregular antibody against red blood cells by indirect antiglobulin test. Further testing determined the specificity of antibody to be anti-Cellano. The detected antibody was found in high titers (1024) with erythrocyte phenotype Kell-Cellano+. The blood donor was found to have a rare blood group KellKell. This donor was excluded from further blood donation. It is difficult to find compatible blood for a person who has developed an antibody to the high-frequency antigen. The donor's family members were tested and Cellano antigen was detected in her husband and child. A potential blood donor was not found among the family members. There was only one blood donor in the Register of blood donors who was compatible in the ABO and Kell blood group system.
Conclusion: For the successful management of blood transfusion it is necessary to establish a unified national register of donors of rare blood groups and cooperate with the International Blood Group Reference Laboratory in Bristol with the database that registers donors of rare blood groups from around the world.