What does a direct ELISA test specifically detect?

A direct ELISA test specifically detects the presence of antigens within a sample. This testing method involves immobilizing the antigen of interest on a solid surface, followed by the addition of a detection antibody that is conjugated to an enzyme. If the antigen is present, the antibody will bind to it, forming a complex. The subsequent addition of a substrate for the enzyme allows for a measurable reaction, creating a signal that indicates the presence and level of that specific antigen.

This method is particularly useful in clinical and research settings for diagnosing infections, allergies, or other conditions where antigens are present. Understanding the presence of antigens rather than antibodies is critical in many scenarios, such as when detecting a pathogen directly from a sample.