In an antibody screening procedure, after adding check cells, what is the most logical next step?

• A. Perform an antibody identification
• B. Run a crossmatch
• C. Perform a direct antiglobulin test
• D. Repeat the screening

Answer: (A)

Check cells are added to verify that the screening test is functioning correctly. When those controls validate the run and the screening cells show reactivity, the next logical step is to identify the antibody by testing a panel of reagent red cells to pinpoint the antibody’s specificity. Knowing the exact antibody guides you to select antigen-negative donor units and then perform the appropriate crossmatch. A direct antiglobulin test isn’t the next step here, as it’s used for different indications, and repeating the screen won’t advance the goal once a valid positive screen is being pursued.