Alloimmunization occurs in about 2-5% of transfused patients, even when ABO and RhD blood groups are matched, and rates are even higher among chronically transfused patients. Extended antigen matching decreases alloimmunization rates, but serologic tests are currently the standard methods used for human erythroid antigens (HEA), and additional methods are used to type platelet (HPA), neutrophil (HNA), and leukocyte antigens (HLA). The Blood transfusion Genomic Consortium, comprised of 18 institutions globally, developed an automated, comprehensive high-throughput genotyping array to simultaneously type 51 HEA variants using 20,681 probes, as well as 8 HPA and 6 HLA. Overall, 7,279 blood donors with extensive typing data, including rare and complex antigens from seven blood services from Europe, North America, Australia, and South Africa were genotyped using the Universal Blood Donor Typing array. Reproducibility between the two separate laboratories for 83% (17,244/20,681) of the probes was over 99%, with robust typing of 44/51 HEA, though reproducibility was lower for seven rare erythroid antigens. Similar reproducibility was observed between laboratories for HPA and HLA probes, exceeding 99%. Concordance between array and clinical genotyping data was 99.9% for HEA genotypes and 99.6% for HPA genotypes. Concordance between array and clinical HLA genotyping data ranged from 99% for European samples to 86% for East Asian samples. Ongoing refinements to the Universal Blood Donor Typing array include validation of HNA variants and further refinement of probes, particularly for rare and complex blood group genotypes. A high-throughput, comprehensive blood genotyping array will ensure better-matched blood products, especially for those at highest risk of alloimmunization.
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