Answer:
By using detection antibodies specific for the infected carrier
Step-by-step explanation:
The enzyme-linked immunosorbent assay (ELISA) assay is widely used in molecular biology (and biochemistry) laboratories to detect and measure antibodies in the blood. The antibodies are specific immunoglobulin proteins produced by B lymphocytes, these molecules bind to specific antigens present in pathogenic microorganisms during adaptive (acquired) immune responses, thereby protecting the organism against infectious agents. In consequence, the ELISA assay is a diagnostic method to assess the immune system responses against pathogenic microorganisms. The ELISA technique is specific because it is possible to use different detection antibodies, which bind to specific antigens in the polystyrene microtiter plate.