Answer:
For the diagnosis of patients having bacterial infection, many immunological tests can be performed by the doctor's like agglutination test and enzyme immunoassays.
Agglutination test: This test confirms the bacterial infection based on antigen-antibody interaction. In this test, patient serum is taken which contains antibody, and latex beads with attached specific antigens are added into it. Agglutination of blood serum confirms the infection of that bacteria whose antigen is used in the test.
Enzyme immunoassays: In this test, the antibody is used which has attached enzyme. This antibody binds to the antigen and the enzyme converts some substrate into a product which have fluorescence. Higher the fluorescence higher is the amount of antigen.