What is antinuclear antibody (ANA)?
Antibodies are substances that are produced by the immune system of the body to fight the germs causing infection.
Sometimes there is abnormal production of antibodies (auto-antibody) that attack the body’s own body systems and tissues leading to autoimmune diseases such as systemic lupus erythematosus (SLE), Rheumatoid Arthritis (RA), scleroderma, Sjogren’s syndrome etc.
Antinuclear antibodies (ANA) are unusual antibodies that are directed against the structures within the nucleus of the cells. Presence of ANA indicates the presence of autoimmune disease.

In what other conditions can ANA test be positive?
ANA test may be positive in persons taking antihypertensives (blood pressure lowering agents) and anticonvulsants (drugs to treat epilepsy) such as procainamide, hydralazine and phenytoin. These are referred to as drug induced ANA positive and does not necessarily indicate the presence of disease.
ANA can be produced in patients with lung diseases such primary pulmonary fibrosis, pulmonary hypertension, Gl diseases such as ulcerative colitis, Crohn’s disease, primary biliary cirrhosis, alcoholic liver disease; blood diseases such as ITP, hemolytic anemia; skin diseases such as psoriasis and pemphigus as well as in elderly and those persons with a family history of rheumatic diseases.

How is the ANA test performed?
ANA test is performed using a blood test. The antibodies in the blood are exposed in the laboratory to cells. It is then tested whether these antibodies are reactive to various parts of the nucleus of cells.


Last updated on 15-12-2003