Final answer:
Enzyme-linked immunosorbent assay (ELISA) is the method of serology described in the question. It involves mixing a patient sample with an enzyme-labeled antibody against the antigen and adding a chemical that produces a colored substance, indicating the presence of the antigen.
Step-by-step explanation:
The method of serology described in the question is called Enzyme-linked immunosorbent assay (ELISA). ELISA involves mixing a patient sample with an enzyme-labeled antibody against the antigen. Then, a chemical is added that produces a colored substance, indicating the presence of the antigen.