What does a positive result in an ELISA test indicate?

In an ELISA (Enzyme-Linked Immunosorbent Assay) test, a positive result indicates the presence of a specific antigen. This immunoassay method is commonly used to detect and quantify proteins, peptides, antibodies, and hormones. In the context of the test, if the specific antigen is present in the sample being tested, it will bind to the antibodies coated on the plate. The subsequent steps in the assay will lead to a measurable signal, such as a color change, that correlates with the amount of antigen present in the sample.

This approach is fundamental in various settings, including diagnostics and research, as it allows for the detection of disease markers, hormonal levels, or other biomolecules of interest. The ability to accurately identify an antigen is crucial for diagnostic purposes, making the ELISA a valuable tool in clinical settings.

While the presence of antibodies is often measured in other types of tests, a positive ELISA focuses specifically on the detection of the target antigen itself. The other options, such as a color change indicating no antigen or high concentrations of proteins, do not accurately describe what a positive ELISA result signifies.