An ANA test detects antinuclear antibodies in your blood. Your immune system normally makes antibodies to help you fight infection. In contrast, antinuclear antibodies often attack your body's own tissues — specifically targeting each cell's nucleus.
In most cases, a positive ANA test indicates that your immune system has launched a misdirected attack on your own tissue — in other words, an autoimmune reaction. But some people have positive ANA tests even when they're healthy.
Your doctor may order an ANA test if he or she suspects you have an autoimmune disease such as lupus, rheumatoid arthritis or scleroderma.
Aug. 31, 2011
- Arend WP, et al. Laboratory evaluation of systemic inflammatory disease. In: Goldman L, et al. Cecil Medicine. 23rd ed. Philadelphia, Pa.: Saunders Elsevier; 2008. http://www.mdconsult.com/das/book/body/191371208-2/0/1492/0.html#. Accessed June 21, 2011.
- Reichlin M. Measurement and clinical significance of antinuclear antibodies. http://www.uptodate.com/home/index.html. Accessed June 21, 2011.
- Tassiulas IO, et al. Clinical features and treatment of systemic lupus erythematosus: Diagnostic tests. In: Firestein GS, et al. Kelley's Textbook of Rheumatology. 8th ed. Philadelphia, Pa.: Saunders Elsevier; 2009. http://www.mdconsult.com/das/book/body/208746819-6/0/1807/0.html. Accessed June 21, 2011.