Phenotype frequencies of Rh (C, c, E, e), M, Mi and Kidd blood group systems among ethnic Thai blood donors from the north-east of Thailand.

We here report the first study of antigen and phenotype frequencies of Rh (C, c, E, e), M, Mi and Kidd antigens in north-east Thai blood donors. Blood transfusion services aim to ensure availability of adequate and safe blood to minimize the development of transfusion reactions. For pre-transfusion testing, the most important blood group systems are ABO and RhD. The transfusion of ABO-compatible otherwise unknown phenotype blood may result in alloimmunization, especially in multi-transfused patients. Extended red blood cell (RBC) phenotyping and selection of blood negative for specific antigens reduce post-transfusion complications and allow for effective blood transfusion regimens to be achieved. A total of 13,567 regular repeated, voluntary Thai blood donors were included for red-cell antigen typing of Rh (D, C, E, c, e). Samples from 12,768, 9,389 and 13,059 donors were typed for Kidd, M and Mi antigens, respectively. Amongst Rh antigens, e was the most common (96.80%) followed by C (95.50%), c (34.40%) and E (32.20%) with CCDee (60.00%) being the most common phenotype. For Kidd phenotypes, Jk(a+b+) was the most common (46.73%) and Jk(a-b-) was rare (0.07%). For the M and Mi antigen, M(+) was most frequently found (94.96%) and Mi (+) was found in 17.97% of individuals. Knowledge of red-cell antigen phenotype frequencies in a population is helpful for creating a phenotype database of blood donors which can provide antigen-negative compatible blood to patients with multiple alloantibodies. Moreover, provision of antigen-matched blood can prevent alloimmunization in multi-transfused patients.