What type of tests involve antigens located on red blood cells (RBCs)?

Agglutination tests are designed to identify the presence of specific antigens located on the surface of red blood cells (RBCs). This type of testing involves mixing serum containing antibodies with a suspension of RBCs. If the antibodies present in the serum recognize and bind to the corresponding antigens on the RBCs, agglutination (clumping) occurs. This reaction indicates a positive result for the presence of the specific antigen, commonly utilized in blood typing and diagnosing certain infections.

The use of agglutination is fundamental in immunohematology, particularly in blood transfusion practices, where matching donor and recipient blood types is critical to avoid transfusion reactions. In contrast, other tests such as complement fixation tests, enzyme-linked immunosorbent assays (ELISAs), and Western blotting do not primarily focus on the antigens present on RBCs; rather, they target soluble antigens or proteins in various biological fluids, serving different purposes in clinical and research settings.