A Rare Case of Bm (Bweak) Phenotype Detected in a Healthy Blood Donor from Eastern India

Abstract

A 52-year-old male repeats voluntary blood donor donated at our blood center for the first time. Historical blood group was O, Rh (D) positive. Initial blood grouping was done on the fully automated immunohematology analyzer using column agglutination technique (CAT). Discrepant results (forward as group O and reverse as group B) were observed while performing the ABO blood grouping by CAT. Repeat testing by conventional tube technique showed the same discrepancy. Antibody detection test and direct antiglobulin test results were negative. After adsorption-elution, the eluate reacted only with group B red cells. Saliva testing for secretor status shows the presence of B and H substances. Finally, it was classified as a case of Bm (now called Bweak) phenotype. As a precautionary measure, the donor was recalled and a special blood group card was issued with a clear mention of his respective donor and recipient status. This case showed the importance of ABO subgroup determination that can help blood centers to establish defined transfusion protocol and prepare an elaborate rare blood donor registry.