Blood group genotyping of blood donors: validation of a highly accurate routine method

BACKGROUND In the past century, blood group determination using serology has been the standard method. Now, molecular methods are gaining traction, which provide additional and easily accessible information. Here we designed and validated a high‐throughput extended genotyping setup. STUDY DESIGN AND METHODS We developed 35 competitive allele‐specific polymerase chain reaction assays for genotyping of blood donors. Samples from 1034 Danish blood donors were genotyped, and 45,314 red blood cell antigens and 6148 platelet antigens were predicted. Predicted phenotypes were compared with 16,119 serologic phenotypes. RESULTS We found 62 discrepancies of which 43 were due to serology. After exclusion of the discrepancies caused by serology, the accuracy of genotyping was 99.9%. Of 17 discrepancies caused by the genotype, three were incorrect antigen‐negative predictions and could potentially, as the solitary analysis, have caused an adverse transfusion reaction. CONCLUSION We have established a robust and highly accurate blood group genotyping system with a very high capacity for screening blood donors. The system represents a significant improvement over the former serotyping‐only procedure. Almost all new technology in medicine incurs increased costs, but the presented efficient genotyping system is a rare example of a significant qualitative and quantitative technologic progress that is also more cost‐efficient than previous technologies.