Generally, immunofluorescence staining is needed for the diagnosis of autoantibodies, immune function tests and tissue and organ specific function indexes. 1. Autoantibodies: can detect or localize various antigens, and can be combined with other proteins to detect or localize antibodies, such as nephritis diagnosis can be detected through the detection of the type of labeled antibody deposition to typify nephritis. 2. Immune function test: It is used to determine the expression of epidermal growth factor 2 (HER-2), which can be positive or negative. For example, immunohistochemical staining of HER-2 in breast cancer tissues shows 2+, which needs to be examined by immunofluorescence staining. Receptor positivity or negativity has an important role in guiding cancer prognosis and drug selection. 3. Tissue- and organ-specific functional indexes: the sections after staining need to be observed under a specific fluorescence microscope to determine the source, nature and location of the test substance according to the fluorescence emitted by the formed immune complexes. Immunofluorescence staining diagnosis needs to be carried out in regular hospitals, and the test results should be interpreted by professional doctors, so as not to cause errors in the test or interpretation of the results, which may delay the disease.