Antibody detection tests: These tests are used to detect the presence of specific antibodies in a person's blood, which can indicate an immune response to a particular infection or disease. For example, an HIV antibody test is used to detect the presence of antibodies to HIV, which can indicate an HIV infection.
Antigen detection tests: These tests are used to detect the presence of specific antigens in a person's blood or other body fluids, which can indicate the presence of an infection or other condition. For example, a rapid antigen test for influenza can detect the presence of influenza virus antigens in a person's nose or throat swab, indicating an active influenza infection.
Antibody titers: These tests measure the concentration of specific antibodies in a person's blood, which can be used to determine the severity of an infection or disease. For example, a measles antibody titer can be used to determine whether a person has immunity to measles.
Agglutination tests: These tests involve the clumping of particles (such as red blood cells or bacteria) in the presence of specific antibodies. For example, the indirect Coombs test is used to detect the presence of antibodies on the surface of red blood cells, which can indicate an autoimmune disorder such as autoimmune hemolytic anemia.
Complement fixation tests: These tests involve the detection of specific antibodies that have bound to and activated complement proteins in the blood. For example, the Wassermann test is used to detect the presence of antibodies to syphilis.
Enzyme-linked immunosorbent assay (ELISA): This test involves the detection of specific antibodies using enzymes and colored reactions. ELISA tests are often used to detect antibodies to HIV, hepatitis, and other infections.