Detection of a new weak A blood-group allele (Aw11)

Background and Objectives  Weak ABO variants may escape tests using unlicensed sera. Materials and Methods  Prior to transfusion, ABO grouping was performed using an automated system and in-house diluted sera, and manual and bedside test techniques. Genotyping and sequencing were performed using standard methods. Results  Initially, the red blood cells (RBC) of the first-time blood donor were typed as B, but pretransfusion testing carried out using the bedside test indicated the presence of an additional A phenotype. Serological re-examination confirmed the bedside test results, and the allele in question was identified, by genotyping, as a new weak A variant (Aw11). Conclusions  The use of CE-marked and licensed antisera is recommended to avoid ABO mistyping.