ANA IgG

A negative ANA titer result suggests that ANA-associated autoimmune diseases are not present, but does not rule out the possibility. People with negative results on the ANA titer usually also have negative results for specific ANA antibodies.

A low ANA titer (1:40 to 1:80) may be associated with preclinical disease or lack of disease. Some normal people have a low level of ANA. Thus, the presence of a low level of ANA is not always abnormal. ANA is reported as a "titer". Low titers are in the range of 1:40 to 1:60. A positive ANA test is of much more importance if you also have antibodies against the double-stranded form of DNA. The presence of ANA does not confirm a diagnosis of systemic lupus erythematosus (SLE). However, a lack of ANA makes that diagnosis much less likely.

Patients with the following systemic autoimmune diseases may have a positive test for antinuclear antibodies (ANA): - Systemic lupus erythematosus (SLE) - Scleroderma - Sjögren's syndrome - Mixed connective tissue disease - Drug-induced lupus - Polymyositis/dermatomyositis - Rheumatoid arthritis - Oligoarticular juvenile chronic arthritis - Polyarteritis nodosum Patients with organ-specific autoimmune diseases may also have a positive test for ANA. These diseases include: - Thyroid diseases (Hashimoto thyroiditis, Grave disease) - Gastrointestinal diseases (autoimmune hepatitis, primary biliary cholangitis [also known as primary biliary cirrhosis], inflammatory bowel disease) - Pulmonary diseases (idiopathic pulmonary fibrosis) Patients with infectious diseases may also test positive for ANA. These diseases include: - Viral infections (hepatitis C, parvovirus) - Bacterial infections (tuberculosis) - Parasitic infections (schistosomiasis) Other associations with positive ANA tests have been noted, including: - Various forms of cancer (rarely) - As a harbinger of the future development of autoimmune disease - Various medications, without causing an autoimmune disease - Having one or more relatives with an autoimmune disease Some individuals, even those without a relative with autoimmune disease, may have a positive test for ANA and yet never develop any autoimmune disease. Additional note: A positive test for antinuclear antibodies (ANA) does not, by itself, indicate the presence of an autoimmune disease. Many normal individuals will have a positive test at low titers. Even when detected at high titer, a positive ANA result, by itself (in the absence of symptoms or physical findings), does not indicate that a patient either has, or will develop, an autoimmune disease. Some ANA appear to be unrelated to the development of autoimmune disorders. Future studies may help identify these "benign" autoantibodies and may permit health care providers to provide reassurance to their patients.