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Anti Nuclear Antibody / Factor (ANA/ANF)

About the test
What is this test done for?
The antibodies targeting “normal” proteins within the nucleus of a cell are called antinuclear antibodies (ANA). The ANA test is a sensitive screening blood test used to detect autoimmune diseases.
Why is it Done?
ANAs could signal the body to begin attacking itself. Therefore, when they are detected in a patient's blood (referred to as a "positive" result), doctors will consider the possibility of an autoimmune illness in that patient e.g. rheumatoid arthritis, Sjogren’s syndrome, Systemic Lupus Erythematosus (SLE), etc.
When should it be performed?
Your doctor will order an ANA test if you show signs of an autoimmune disorder. An ANA test can indicate that you have an autoimmune condition, but it can’t diagnose a specific disorder. If a patient has the following symptoms, the doctor might order it-
  • Joint swellings
  • Recurrent fevers
  • Sensitivity to light
  • Sudden rash over the joints or body
How is it done
A blood sample will be collected from a vein in your arm. Fluorescence techniques are frequently used to detect the antibodies in the cells. Thus, ANA testing is sometimes referred to as fluorescent antinuclear antibody test (FANA).
Results
A positive ANA reading alone does not indicate an autoimmune disease.
  • Even healthy people with viral infections can have a positive ANA, although for a short time.
  • Some medications can also cause a positive ANA. It is important to talk with your doctor about all the drugs that you are taking.
  • Other conditions, such as cancer, can cause a positive ANA.
However, some conditions that are associated with a positive ANA test include systemic lupus erythematosus (lupus), chronic liver disease (cirrhosis), rheumatoid arthritis, Sjögren’s syndrome, scleroderma, thyroid disease, or temporal arteritis. The ANA test is especially helpful in diagnosing lupus since more than 95 percent of people with lupus test positive for ANA. However, not everyone who tests positive for ANA has lupus and not everyone with lupus tests positive for ANA.
Other Tests
These tests might be done to further confirm the exact condition-
  • Anti-DNA antibody
  • Antiphospholipid antibody
  • Anti-smooth muscle antibody
  • Anti-mitochondrial antibody
  • Acetylcholine receptor antibodies
  • C reactive protein to assess inflammatory origin
  • Erythrocyte sedimentation rate. (ESR) to assess presence of inflammation