An immunoassay test is used to detect what?

An immunoassay test is specifically designed to detect the presence of antibodies or antigens in a sample, which are crucial indicators of immune responses to infections or diseases. In this context, when the test is utilized to detect an infectious agent antibody, it indicates whether the body has produced an immune response to a specific infectious pathogen. This ability to identify antibodies is particularly useful in diagnosing infections, determining immunity to certain diseases, and monitoring the effectiveness of vaccines.

While immunoassays can indirectly relate to the other answer choices, such as measuring hormonal levels or detecting autoimmune markers, their primary function revolves around the detection of antibodies related to infectious agents. This is what distinctly characterizes immunoassays compared to other types of diagnostic tests, such as complete blood counts, which focus on evaluating blood components rather than immune responses.