Background
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Anti-nuclear antibodies (ANAs, also known as anti-nuclear factor or ANF) are antibodies directed against contents of the cell nucleus.They are present in higher than normal numbers in autoimmune disease. The ANA test measures the pattern and amount of autoantibody which can attack the body's tissues as if they were foreign material. Autoantibodies are present in low titers in the general population, but in about 5% of the population, their concentration is increased, and about half of this 5% have an autoimmune disease. Normal titer of ANA is 1:40. Higher titers are indicative of an autoimmune disease. The presence of ANA is indicative of lupus erythematosus (present in 80-90% of cases), though they also appear in some other auto-immune diseases such as Sj ? gren's syndrome (60%), rheumatoid arthritis, autoimmune hepatitis, scleroderma and polymyositis & dermatomyositis (30%), and various non-rheumatological conditions associated with tissue damage. ANA are also directed to the nuclear pore complex in primary biliary cirrhosis. Other conditions with high ANA titre include Addison disease, Idiopathic thrombocytopenic purpura (ITP), Hashimoto's, Autoimmune hemolytic anemia, Type I diabetes mellitus, Mixed connective tissue disorder.
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