Antinuclear Antibodies (ANA)
An antinuclear antibody (ANA) test measures the amount and pattern of antibodies in your blood that work against your own body (autoimmune reaction).
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. Rheumatoid arthritis and systemic lupus erythematosus 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 antinuclear antibodies (ANA) test is done to help identify problems with the immune system, such as:
How To Prepare
You do not need to do anything before you have this test.
Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).
How It Is Done
The health professional drawing blood will:
How It Feels
The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight. You may feel nothing at all from the needle, or you may feel a quick sting or pinch.
There is very little chance of a problem from having a blood sample taken from a vein.
An antinuclear antibody (ANA) test measures the amount and pattern of antibodies in your blood that work against your own body (autoimmune reaction). If there are more antibodies in the blood than normal, the test is positive. When the test is positive, most labs do other tests right away to look for the cause. These tests can find out which antibodies are in the blood in higher amounts than normal.
A positive ANA test may be caused by:
What Affects the Test
Reasons you may not be able to have the test or why the results may not be helpful include:
What To Think About
eMedicineHealth Medical Reference from Healthwise
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