Direct Coombs' Test (DAT)

A qualitative immunoassay to detect the presence of antibodies (IgG) and/or complement components (C3) attached to the surface of red blood cells in a blood sample. This test is considered fundamental in diagnosing autoimmune hemolytic anemia (AIHA), diagnosing hemolytic transfusion reactions, and diagnosing hemolytic disease of the newborn (HDN).