Antinuclear antibodies, also known as anti-nucleic acid antigen antibodies, are autoantibodies produced against various components of the nucleus of one’s own eukaryotic cells, including DNA, RNA, deoxyribonucleoproteins and complexes of these molecules. Antinuclear antibodies are a general term for non-specific anti-autoantibodies to organs that use the nuclear components of eukaryotic cells as putative antigens, and this test is a routine screening test for autoimmune diseases. It appears positive to varying degrees in many immune diseases, commonly including systemic lupus erythematosus, dry syndrome, mixed connective tissue disease, and systemic scleroderma. Therefore, when positive antinuclear antibodies are present, a high degree of attention needs to be paid to the presence of autoimmune diseases. However, it is not possible to rely only on this index to confirm the diagnosis, and it is necessary to combine the patient’s clinical symptoms and other tests, such as autoantibody spectrum, rheumatoid factor, anti-cyclic cysteine antibody, etc., to make a comprehensive judgment. As a screening test for autoimmune diseases, antinuclear antibody test provides a diagnostic basis for the screening of a variety of clinical diseases.