What does the acronym DAT stand for in immunohematology?

• A. Direct Antigen Test
• B. Direct Antiglobulin Test
• C. Determinant Antibody Test
• D. Direct Agglutination Test

Answer: (B)

Direct Antiglobulin Test. It detects antibodies or complement bound directly to a person’s red blood cells in vivo. In practice, washed patient red cells are exposed to anti-human globulin; if IgG or C3d is coating the cells, the anti-globulin causes agglutination, yielding a positive result. This test helps diagnose immune-mediated hemolysis, such as autoimmune hemolytic anemia, transfusion reactions, or hemolytic disease of the newborn. It’s different from the indirect antiglobulin test, which screens for antibodies in serum by testing serum against donor red cells and then adding anti-human globulin. The other option names aren’t standard for this assay because they describe either antigen detection or nonstandard terms.