Test Overview

An antinuclear antibody (ANA) test looks for the presence of certain types of autoantibodies in the blood. Autoantibodies are types of antibodies in your blood that work against your own body (autoimmune reaction). Antinuclear antibodies target your cell's nucleus and other cellular parts.

The body's immune system normally attacks and destroys foreign substances such as bacteria and viruses. But in disorders known as autoimmune diseases, the immune system attacks and destroys the body's normal tissues. When a person has an autoimmune disease, the immune system produces antibodies that attach to the body's own cells as though they were foreign substances, often causing them to be damaged or destroyed. Systemic lupus erythematosus and autoimmune inflammatory myositis are examples of autoimmune diseases.

An ANA test is used along with your symptoms, physical examination, and other tests to find an autoimmune disease.

Why It Is Done

An ANA test is done when your doctor thinks you may have an autoimmune disease, especially systemic rheumatic disease, such as:

• systemic lupus erythematosus
• autoimmune inflammatory myositis
• scleroderma
• Sjogren's disease
• mixed connective tissue disease
• juvenile idiopathic arthritis

How To Prepare

In general, there's nothing you have to do before this test, unless your doctor tells you to.

How It Is Done

An ANA test is a type of blood test. A health professional uses a needle to take a blood sample, usually from the arm.

How long the test takes

Taking the blood sample can take several minutes. It can take several days for the test results to be reported.

Watch

How It Feels

When a blood sample is taken, you may feel nothing at all from the needle. Or you might feel a quick sting or pinch.

Risks

There is very little chance of having a problem from this test. When a blood sample is taken, a small bruise may form at the site.

Results

ANA test results can tell your doctor about how reactive the autoantibodies are. The test results can also give your doctor some information about which antibodies are present. These are called the ANA titer and patterns. Knowing this information is one thing that can help your doctor make a diagnosis. If there are more autoantibodies present in the blood over a certain titer, the test is positive.

A positive ANA test also does not diagnose an autoimmune disease, and the results do not directly relate to your experience of the disease. Having serious symptoms or many symptoms of an autoimmune disease, for example, may not mean that your test results will show high reactivity.

The pattern of the ANA test can give information about which antibodies are present and are associated with the underlying autoimmune disease, but identifying a specific autoimmune disease usually needs more specific follow-up tests.

Positive test

A positive ANA test can also be seen un up to 1 in 5 healthy individuals. Beause the ANA test is not looking for a specific disease, a positive test can also be caused by conditions that might cause autoantibodies, including infections, cancer, multiple sclerosis, or thyroid disease. For these conditions, having a positive ANA test does not help your doctor diagnose the condition.