ANA Test

An antinuclear antibody test, or ANA test, is a test that checks your blood for possible signs of an autoimmune disease. Autoimmune diseases happen when your immune system attacks your own cells. Antinuclear antibodies (ANAs) are one way your immune system can target your own cells.

What are antinuclear antibodies?

Antibodies are your body’s version of a “WANTED” poster. They circulate in your blood so your immune system can recognize and react quickly to germs like viruses or bacteria.

ANAs are autoantibodies, meaning they label your own cells for attack. ANAs get their name from how they target the nucleus of a cell. The higher the level of ANAs, the more likely you are to have an autoimmune disease.

What is an ANA test used for?

Your healthcare provider may want to run an ANA test if they suspect you have an autoimmune disease. That includes diseases like:

• Autoimmune hepatitis
• Juvenile onset idiopathic arthritis (JIA)
• Mixed connective tissue disease (MCTD)
• Polymyositis or dermatomyositis
• Psoriatic arthritis
• Scleroderma
• Sjögren’s syndrome
• Systemic lupus erythematosus (SLE), also known as lupus

Some cancers or related paraneoplastic syndromes can also cause a positive ANA test.

How an ANA test works

An ANA test starts with a blood draw. A healthcare provider, like a phlebotomist, will insert a needle into a vein (usually one on your arm). They’ll then collect some of your blood into one or more sample tubes. Once they’ve drawn your blood, they’ll take the needle out and put a bandage over the needle site. After that, your part of the test is over.

A pathologist will take your blood samples and prepare them for analysis. The most common method for preparing the samples is called indirect immunofluorescence (IIF). That makes antinuclear antibodies in the sample glow when viewed with a fluorescent microscope. The pathologist can then view the sample under a microscope to look for glowing cells. They’ll also look for different patterns in how the affected cells glow.

What to expect after the blood draw?

After your blood sample is drawn, it can take a few days to get your results. Your healthcare provider will tell you how long it usually takes and when you can expect to learn the results.

The results you'll get and what they mean

There are three main parts of ANA test results:

• Interpretation: This is whether or not the test detected ANAs. If the test detects ANAs, that means a positive result.
• Titer reading: This is the concentration of the antibodies. The higher the concentration, the more antibodies there are. And the more antibodies you have, the more likely you are to have an autoimmune disease.
• Fluorescent pattern: ANAs target different things. And what they target determines where they latch onto a cell’s nucleus. Some ANAs make the whole surface of the nucleus glow. Others might just appear as glowing speckles or dots on the nucleus’ surface. Certain patterns may suggest a specific autoimmune disease.

Your provider can tell you more about the specifics of your results and what they mean.

What does a positive ANA result mean?

A positive ANA result means the test detected ANAs in your blood. But it’s important to remember that a positive ANA test doesn’t automatically mean you have an autoimmune disease. Up to 3 in 10 people who don’t have an autoimmune disease will still have a positive ANA test. You can also have a positive ANA test when you have a viral infection or when you take certain medicines.

If your test is positive, your healthcare provider will likely recommend additional testing. That can help them confirm or rule out an autoimmune disease. And if you have one, further testing can narrow down which you have.