What is the primary goal of the antibody screen?

• A. Identify autoantibodies to red cells
• B. Confirm ABO compatibility
• C. Screen for alloantibodies to non-ABO antigens
• D. Detect ABO antibodies

Answer: (C)

The antibody screen is used to find unexpected antibodies directed against red cell antigens other than ABO. By testing the patient’s serum against a panel of reagent red cells that express a broad range of non-ABO antigens (such as Rh, Kell, Duffy, Kidd, MNS, and others), any alloantibodies present can be detected. If a clinically significant alloantibody is identified, donor units can be matched to lack the corresponding antigen to prevent a transfusion reaction. This screening complements, but is distinct from, ABO typing and crossmatching, which focus on ensuring ABO compatibility. It is not primarily about detecting ABO antibodies, which are addressed through the standard ABO compatibility process.