Which test measures the coating of red cells by antibodies in hemolytic transfusion reactions?

The test that measures the coating of red cells by antibodies in hemolytic transfusion reactions is the direct antiglobulin test (DAT). This test is specifically designed to detect antibodies that are attached to the surface of red blood cells. In the context of hemolytic transfusion reactions, the DAT helps to confirm the presence of antibodies that may have been introduced from the donor's blood into the recipient's system, leading to the lysis (hemolysis) of red blood cells.

When performing the DAT, a sample of the patient's blood is mixed with a reagent that contains antihuman globulin. If red blood cells are coated with antibodies, the antihuman globulin will bind to these antibodies, causing visible agglutination or clumping of the red blood cells. This agglutination indicates that the patient's immune system has reacted to the transfused red blood cells, which is characteristic of hemolytic reactions.

In contrast, tests like the indirect antiglobulin test (IAT) are used to detect antibodies in the serum that may attach to red blood cells, typically in a pre-transfusion setting rather than assessing the immediate reactions. ELISA is a different methodology used mainly for detecting proteins or antibodies in a sample, rather than