High‐throughput K ell, K idd, and D uffy matrix‐assisted laser desorption/ionization, time‐of‐flight mass spectrometry–based blood group genotyping of 4000 donors shows close to full concordance with serotyping and detects new alleles

Background After the ABO ( ABO ) and R h ( RHD and RHCE ) blood group systems, K ell ( KEL ), K idd ( SLC 14A1 ), and D uffy ( DARC ) represent the second most important clinically relevant antigens. Study Design and Methods Samples from 4000 S wiss blood donors, with serologic prevalues for K /k, K p a/b , J k a/b , and F y a/b , and 48 additional samples of presumptive black A frican origin were genotyped using high‐throughput matrix‐assisted laser desorption/ionization, time‐of‐flight mass spectrometry, applying one single‐multiplex polymerase chain reaction/primer‐extension reaction simultaneously detecting 15 single‐nucleotide polymorphisms. Results Genotype/phenotype concordance for K /k, K p a/b , J k a/b , and all F y a/b specificities were 100, 99.98, 99.93, and 99.20%, respectively. Discrepancies were caused by erroneous serologic profiles (n = 33), mainly attributed to weakly expressed F y x (n = 28). Only three discrepancies had a genetic basis. They could all be explained by newly observed silenced alleles: one KEL * 02 N .34 and one FY * 02 N .03 with predicted R 700 Q and G 261 R amino acid exchanges, respectively, and one JK * B , with an as‐yet‐unidentified silencing cause. According to NCBI SNP database entry for rs8176034, another new allele, KEL * 02.38 , had been expected, and we formally demonstrated its presence. We furthermore identified individuals with rare phenotypes, such as J s a/b heterozygotes among C aucasians, rare alleles, the “ S wiss” JK * 01 N .03 , and rare genotypes, such as one F y x homozygote. Conclusion Genotyping proved its practicability in the daily routine setting and qualitatively outperformed serology. Technology is ideal for time‐insensitive donor genotyping and allows for a broad range of throughput needs. Consequently, from a technologic point of view, serotyping should be replaced by genotyping for donors' blood groups encoded by KEL , SLC 14 A 1 , and DARC .