IMMUNOHISTOCHEMISTRY is a diagnostic method that consists of using an antibody against a specific structure of interest in the tissue being studied.
In the direct method, the antibody is labeled with a fluorescent substance (immunofluorescence) or with a substance capable of causing a chemical reaction with color production (immunoperoxidase).
The presence and intensity of fluorescence or staining indicate the quantity of the structure of interest.
In the indirect method of immunohistochemical examination, a second antibody against the first is used, and this second antibody is labeled with a fluorescent substance or dye.
This diagnostic method is also applied to cytological samples and histological sections of material embedded in paraffin, and it is used to diagnose diseases based on the antigen-antibody reaction, such as primary site cancer.
