Final answer:
Serological antibody tests like ELISA are used to detect and quantify antigens or antibodies, diagnose diseases, and are highly sensitive for measuring substances like pathogens and hormones.
Step-by-step explanation:
Serological Antibody Tests: ELISA
Serological antibody tests, such as the Enzyme-linked Immunosorbent Assay (ELISA), are utilized to detect and quantify specific antigens or antibodies in a sample, which is especially helpful in diagnosing diseases. The sandwich ELISA involves capturing antigens with a primary antibody and then detecting them with a secondary antibody linked to an enzyme to produce a color change. The intensity of the color change is proportional to the quantity of the antigen. The indirect ELISA is used to identify antigen-specific antibodies in patient serum. This is particularly useful for diagnosing infections such as Lyme disease and HIV. The highly sensitive nature of ELISAs allows for detection and quantification of antigens in very small amounts, typically in the nanogram per milliliter range.
ELISA tests are significant diagnostic tools because they are highly sensitive, can be quantitatively accurate, and provide critical information about the presence of various substances, including pathogens, serum proteins, and hormones. These assays are critical in clinical settings for disease diagnosis, in pharmaceutical applications to monitor drug levels, and in research to measure the concentrations of molecules of interest.