Anti-nuclear antibodies (ANA) are autoantibodies directed against components of the cell nucleus. They are found in many connective tissue diseases, such as systemic lupus erythematosus (SLE). ANA testing is used to help diagnose autoimmune diseases.
What Are Anti-Nuclear Antibodies?
Anti-nuclear antibodies (ANA) are autoantibodies that target the components of the cell nucleus. The nucleus is the control center of a cell, where genetic material is stored. These autoantibodies are made by the body’s immune system in response to an infection or some other type of stress. ANA are found in many autoimmune diseases, including systemic lupus erythematosus (SLE).
What Does It Mean for the ANA Test to Be Positive?
A positive ANA test means the body has produced autoantibodies directed against the nucleus of its own cells. This suggests the presence of an autoimmune disorder, such as lupus, rheumatoid arthritis, or Sjögren’s syndrome. However, it’s important to note that a positive ANA test does not necessarily mean the person has an autoimmune disorder. The test can be positive in healthy people, especially those over the age of 65.
What Other Tests Are Used to Diagnose Autoimmune Diseases?
In addition to the ANA test, other tests may be used to diagnose autoimmune diseases, such as a complete blood count (CBC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) tests. Imaging tests, such as X-rays and MRI scans, may also be used to detect joint damage caused by autoimmune disorders.
Finally, tissue biopsy may be performed to examine the cells and tissues for signs of autoimmune disease. A biopsy can help confirm a diagnosis and rule out other conditions with similar symptoms.