There are several detection methods in IHC, including:
Enzymatic detection: The secondary antibody is conjugated to an enzyme such as horseradish peroxidase (HRP) or alkaline phosphatase (AP). A substrate for the enzyme is added, which produces a colored precipitate at the site of the antigen. Fluorescent detection: The secondary antibody is conjugated to a fluorescent dye. When exposed to a specific wavelength of light, the dye emits fluorescence that can be detected using a fluorescence microscope. Chromogenic detection: Similar to enzymatic detection, but uses chromogens that produce a visible color reaction.
