Background: Traditionally, red blood cell antigens have been identified using serological methods, but recent advances in molecular biology have made the implementation of methods for genetic testing of most blood group antigens possible. The goal of this study was to validate the performance of the ID CORE XT blood group typing assay.
Materials and methods: One thousand independent samples from donors, patients and neonates were collected from three research institutes in Spain and the Netherlands. DNA was extracted from EDTA-anticoagulated blood. The data were processed with the ID CORE XT to obtain the genotypes and the predicted blood group phenotypes, and results were compared to those obtained with well-established serological and molecular methods. All 1,000 samples were typed for major blood group antigens (C, c, E, e, K) and 371-830 samples were typed for other antigens depending on the rarity and availability of serology comparators.
Results: The incorrect call rate was 0%. Four "no calls" (rate: 0.014%) were resolved after repetition. The sensitivity of ID CORE XT for all phenotypes was 100% regarding serology. There was one discrepancy in E- antigen and 33 discrepancies in Fyb- antigen. After bidirectional sequencing, all discrepancies were resolved in favour of ID CORE XT (100% specificity). ID CORE XT detected infrequent antigens of Caucasians in the sample as well as rare allelic variants.
Discussion: In this evaluation performed in an extensive sample following the European Directive, the ID CORE XT blood genotyping assay performed as a reliable and accurate method for correctly predicting the genotype and phenotype of clinically relevant blood group antigens.