Which donor blood compatibility scenario would be easiest to satisfy for a patient with anti-Le^a antibodies?

• A. anti-Le^a positive patient
• B. anti-E positive patient
• C. anti-K negative patient
• D. D positive patient

Answer: (A)

When a patient has anti-Le^a antibodies, the goal is to transfuse red cells that do not express the Le^a antigen. The simplest way to ensure this is to choose a donor whose red cells lack Le^a (Le(a-)). A donor described as anti-Le^a positive is the one most consistent with Le(a-) red cells, since their plasma contains anti-Le^a antibodies but their red cells do not present the Le^a antigen for the antibodies to react with. The other options involve different antigens or antibodies (E, K, or D) that could introduce separate incompatibilities if the recipient has corresponding antibodies, making them less directly protective against Le^a–related reactions.