What is the role of crossmatching in transfusion safety?

• A. It ensures ABO/Rh compatibility between donor and recipient
• B. It ensures the unit is stored properly
• C. It ensures patient consent is obtained
• D. It ensures the label is scannable

Answer: (A)

Crossmatching provides a final compatibility check to ensure the recipient’s antibodies won’t attack the donor’s red blood cells. By testing the recipient’s plasma against the donor cells (and sometimes the donor plasma against the recipient's cells), we look for any antibody–antigen reactions that could cause agglutination or hemolysis. If the test is compatible, it confirms that the specific donor unit will be safe for that patient, supporting ABO and other antigen compatibility for the transfusion and helping prevent acute hemolytic transfusion reactions. Storage, patient consent, and labeling are not determined by the crossmatch.