Evidence that donors with variant RH genotypes are associated with unexpected Rh antibodies.

We show direct association of plasma anti-C with transfusion of a C-negative unit with variant RH encoding partial D and uncommon V/VS+ hr - phenotype. The antibody was transient, without evidence of compromised survival of transfused RBCs. The +DAT and WAA complicated workups and selection of units, and it is uncertain whether donors of the same genotype should be avoided. Minority donors are important for CEK-matching to avoid depleting Rh-negative supplies. Consideration of patient and donor RH genotypes may avoid unexpected antibodies and improve allocation of rare donations.