Make sure you understand the results of your ANA test. Ask what other tests you need for your diagnosis to be confirmed. Also find out how your test results will affect your treatment.
Antinuclear Antibody Test
An antinuclear antibody test is a blood test that looks for certain kinds of antibodies in your body. It’s also called an ANA or FANA (fluorescent antinuclear antibody) test.
Antibodies are proteins that your immune system makes to fight off bacteria, viruses, and other germs. But sometimes, your immune system can mistake parts of your own body for foreign invaders. It releases special antibodies, called “autoantibodies,” that attack your cells and tissues. Autoantibodies can damage your joints, skin, muscles, and other parts of your body. And they can be a sign of autoimmune diseases, including:
- Systemic lupus erythematosus, the most common type of lupus
- Rheumatoid arthritis
- Scleroderma
- Sjogren’s syndrome
Sometimes people with cancer or people taking certain medications test positive on an ANA test. Some people with no health conditions test positive on ANA tests.
Why Would I Need This Test?
Your doctor might order an ANA test if you have symptoms of an autoimmune disease, such as:
- Joint and/or muscle pain, stiffness or swelling
- Tiredness
- Recurring or persistent fever
- A red rash on the cheeks and bridge of the nose that looks like a butterfly
- Weakness
- Light sensitivity
- Numbness and tingling in your hands or feet
- Hair loss
Preparing for an ANA Test
You usually don’t need to prepare for an ANA test. But let your doctor know ahead of time what medicines, vitamins, and supplements you take. They can affect the ANA test results.
Antinuclear Body Test Procedure
A lab tech will take a sample of your blood — usually from a vein in your arm. They’ll tie a band around the upper part of your arm to make your vein fill with blood and swell up. Then they’ll clean the area with an antiseptic and insert a needle into your vein. Your blood will collect into a vial or tube.
The blood test should only take a couple of minutes. After your blood is drawn, the needle and band will be removed, and you’ll get a piece of gauze and a bandage placed over the area.
The blood sample will go to a lab to be tested. The lab will check to see if there are antinuclear antibodies in your blood.
Antinuclear Body Test Risks
The blood test has very few risks. You might feel a slight sting as your blood is drawn. You may notice a small bruise later.
You may also have a slight chance of:
- Dizziness or fainting
- Bleeding
- Soreness
- Bruising
Antinuclear Antibody Test Results
Your test is positive if it finds antinuclear antibodies in your blood. A negative result means it found none. A positive test doesn’t mean that you have an autoimmune condition. Between 3% and 15% of people with no conditions have antinuclear antibodies. Some medicines or other diseases also can cause them.
Not everyone who has an autoimmune disease will test positive. That’s why the ANA blood test is just one part of a doctor’s autoimmune disease diagnosis. They’ll also consider your symptoms, do a physical exam, and most likely do other tests.
Conditions that usually cause a positive ANA test include:
- Systemic lupus erythematosus
- Sjögren’s syndrome — a disease that causes dry eyes and mouth
- Scleroderma — a connective tissue disease
- Rheumatoid arthritis — this causes joint damage, pain, and swelling
- Polymyositis — a disease that causes muscle weakness
- Mixed connective tissue disease — a condition that has symptoms of lupus, scleroderma, and polymyositis
- Juvenile chronic arthritis — a type of autoimmune arthritis that affects children
- Dermatomyositis — a rare disease that causes weak muscles and a rash
- Polyarteritis nodosa — a rare disease that causes the blood vessels to swell up and damage organs
- Autoimmune hepatitis
The ANA test result can sometimes also be positive if you have one of these conditions:
- Raynaud’s syndrome — a disease that makes your fingers and toes turn blue and feel cold
- Thyroid diseases — Hashimoto’s thyroiditis, Grave’s disease
- Liver diseases — autoimmune hepatitis, primary biliary cirrhosis
- Inflammatory bowel disease
- Lung diseases — idiopathic pulmonary fibrosis
- Cancer
- Viral infections
About 20% of healthy people will test positive for antinuclear antibodies, even though they don’t have an autoimmune disease. You’re more likely to have a false positive result if you:
- Are a woman age 65 or older
- Have an infection such as mononucleosis or tuberculosis
- Take blood pressure or anti-seizure drugs
Would I Need Any Other Tests?
The ANA test only shows that you may have an autoimmune disease; it can’t detect the exact one.
If your ANA test is positive, your doctor might test you for ANAs that are specific to certain diseases:
- An anti-centromere test diagnoses scleroderma.
- An anti-double-stranded DNA (anti-dsDNA) test diagnoses lupus.
- An anti-histone test diagnoses lupus that was caused by medicine you took.
- An ENA panel helps your doctor see which autoimmune disease you have.
Make sure you understand the results of your ANA test. Ask what other tests you need for your diagnosis to be confirmed. Also find out how your test results will affect your treatment.
Show Sources
American Association for Clinical Chemistry: “ANA.”
American College of Rheumatology: “Antinuclear Antibodies (ANA).”
Cleveland Clinic: “Antinuclear Antibody Test in Children.”
Lupus Research Alliance: “A Positive ANA Test: Should You Worry?”
Mayo Clinic: “ANA test: How you prepare.” “Results,” “Why It’s Done.”
National Heart, Lung, and Blood Institute: “What to Expect With Blood Tests.”
UpToDate: “Antinuclear antibodies (ANA) (Beyond the Basics).”
MedLine Plus: “ANA (Antinuclear Antibody) Test.”
National Health Service: “Overview: Blood Tests.”
Frontiers in Immunology: “Autoantibodies in Autoimmune Liver Disease—Clinical and Diagnostic Relevance.”
Johns Hopkins Lupus Center: “Lupus Blood Tests.”
What is a positive ANA and what does it mean?
What does it mean to have a positive ANA also known as an antinuclear antibody? This is a loaded question and the answer is complex. The answer is usually quite personalized to the person and their symptoms. The answer also usually entails follow-up bloodwork and evaluation by a rheumatologist. But in simple terms, an ANA is an antibody directed towards the nucleus of a cell.
How is an ANA measured?
The ANA is calculated by taking a standardized cell from the lab and mixing it with a person’s blood. If a person has antinuclear antibodies, these will stick to the standardized cells’ nuclei. At this point, there’s no way for us to know whether this has happened, so the lab tech adds fluoresceinated antibodies to the mix. These antibodies bind to ANAs that stuck to a nucleus. With the help of a specialized microscope, the lab tech can now visualize the ANA because the fluoresceinated antibodies make them light up.
My doctor told me my ANA was high. What does that mean?
Unfortunately, the tech cannot count how many ANAs they see. Instead, they see how much they can dilute the blood and still see the fluoresceinated antibodies. So when you see and ANA of 1:80, that means the tech really wasn’t able to dilute very much. This is a low level. If you see a value of 1:640, that means they were able to dilute a lot more. This is a higher level.
So how much dilution is enough to consider an ANA as positive? That answer really depends on the lab. Every lab has different cut off values, but in general, an ANA of 1:80 is typically considered positive. Whether it’s clinically significant, is a whole different question. This is where the art of medicine comes into play. But before that, let’s talk about patterns because those are important too.
Positive ANA patterns
So let’s take an example. Your doctor runs an ANA and it comes back as 1:320 speckled pattern. So what does that mean? When the lab tech was looking at the fluoresceinated antibodies, it basically literally looked speckled. There are many other kinds of patterns: homogenous, centromere, nucleolar, speckled, rim etc. Each of these patterns possibly indicate the presence of specific nuclear antibodies. For example, the presence of a speckled positive ANA indicates the presence of these specific autoantibodies, SSA, SSB, RNP, Smith, and Ku antibodies. These specific nuclear antibodies are themselves associated with specific autoimmune diseases. It’s important to take ANA patterns with a grain of salt because interpretation highly depends on experience.
I’m not going to go more into details about specific nuclear antibodies because first, there’s about 150 of them and second, they’re all associated with different diseases lupus being one of them. That’s a lot of material to cover in one article.
When is a positive ANA clinically significant?
Now that we understand what an ANA actually is, we can now start to approach the subject of clinical significance AND when you should be tested.
The problem with the ANA is that it can be found in normal healthy people.
- ANA 1:40 is found in 20 – 30% of healthy people
- ANA 1:80 is found in 10 – 15% of healthy people
- ANA 1:160 is found in 5% of healthy people
- ANA 1:320 is found in 3% of healthy people
- 5 – 25% of healthy people with a family member suffering from lupus have a positive ANA
- Up to 70% of people aged above 70 years have a positive ANA
To complicate things even more, someone who is about to have and autoimmune disease can have a positive ANA… UP TO 10 YEARS before they actually develop the disease. Cancer and infections can also cause someone to have a positive ANA. It can even be positive when people are taking certain medications. Not terribly helpful right?
Bad example
So someone runs an ANA just because and it’s positive.
- Does it mean anything?
- Is the person one of those healthy people that has a positive ANA?
- Is the person going to develop an autoimmune disease in the future?
In this scenario, I would say that this test is of low clinical significance because that person did not have any symptoms. Because so many people who are completely healthy have an ANA, the test should only be run if a person has a symptom or better yet, multiple symptoms that potentially indicate the presence of an autoimmune disease like lupus, Sjögren’s syndrome, systemic sclerosis, mixed connective tissue disease, etc. In that situation, it is helping rule in or rule out certain diagnoses.
Good example
If you’ve read my earlier post, 8 important warning signs of scleroderma, you’ll remember that Raynaud’s phenomenon is an important red flag for scleroderma. The majority of people suffering from Raynaud’s have no underlying autoimmune disease but a small proportion does. This is the perfect scenario, where an ANA would be useful. If the ANA is negative, the person likely will NOT develop an autoimmune disease. If the ANA is positive, then the person has a high risk of developing an autoimmune disease like lupus, scleroderma or Sjogren’s syndrome.
Let’s wrap things up
Ultimately it all boils down to this simple fact: doctors treat people not numbers.
As a physician I care about symptoms and signs way more than lab tests. Don’t get me wrong, these tests are important. For example, over 99% of people suffering from systemic lupus erythematosus have a positive ANA. It’s pretty much safe to say that if someone tests negative for ANA, they likely don’t have lupus. FYI that other less than 1% usually have a positive SSA, they have a problem with their complement system, or they have a lot of protein in their urine (nephrotic syndrome).
I hope I’ve helped you better understand the elusive and mysterious positive ANA. If you’ve tested positive for an ANA and have more questions, I highly urge you to speak with your physician or local rheumatologist. And remember, doctors treat people not numbers.
References
Rheumatology Secrets 3 rd edition
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This information is offered to educate the general public. The information posted on this website does not replace professional medical advice, but for general information purposes only. There is no Doctor – Patient relationship established. We strongly advised you to speak with your medical professional if you have questions concerning your symptoms, diagnosis and treatment.
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