When a screening cell positive has not been investigated, what is the appropriate action?

• A. Identify the antibody causing the positive screening cell
• B. Ignore the positive screen and continue
• C. Transfuse without further testing
• D. Request a repeat sample and perform antibody identification

Answer: (C)

When a screening cell is positive, you must investigate to determine if and which antibody is present before giving a transfusion. The positive result flags a potential alloimmune reaction, and without identifying the antibody and matching appropriately, transfusing could cause a hemolytic reaction. The safest course is to obtain a repeat sample to confirm the result and perform antibody identification (and, if needed, antigen typing and crossmatching) so you can select antigen-negative units. Ignoring the screen or transfusing without this workup risks patient safety.