[Genotyping of 21,000 blood donors in Quebec and RHD analysis]

A repeat blood donor genotyping project was launched by Héma-Québec in October 2007. The objective was to screen 21,000 samples for 22 polymorphisms for red blood cell and platelet blood groups to build a database to easily find compatible donors.

Donors who have donated at least three times during the last year were selected. A drop of blood was spotted on FTA paper and sent to the Pharmacogenomic Centre at the Montreal Heart Institute for analysis. All genotype results were compared to the known phenotype. In parallel, the RHD gene of D negative blood donors was examined.

Less than two years were necessary to complete the database. The genotype/phenotype concordance was 99.6% with only 165 discrepancies observed and further analysed. More than 55% of these discrepancies confirmed the initial genotype. The RHD study done on D negative samples found 13 donors positive for a variant RHD gene. Four were RHD*Ψ positive, while the other nine presented variant polymorphisms precluding a reduced expression of the D antigen.

Thanks to this project, Héma-Québec is able to answer increasing demands for compatible blood more rapidly. The organisation has also demonstrated the security of its D negative inventory.