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ANA (Antinuclear Antibody) Test
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Lab Tests

ANA (Antinuclear Antibody) Test

The ANA test is a blood test used to detect antinuclear antibodies, which can be a sign of an autoimmune disorder.

What is an ANA (antinuclear antibody) test?

An ANA test looks for antinuclear antibodies in your blood. While antibodies are normally produced by the immune system to fight foreign substances like bacteria, antinuclear antibodies mistakenly attack the nucleus of your own healthy cells. A high number of these antibodies can be a sign of an autoimmune disorder, where the immune system attacks the body's own organs and tissues.

What is it used for?

The test helps diagnose various autoimmune conditions, including:

  • Systemic lupus erythematosus (SLE): A chronic disease affecting joints, skin, heart, lungs, blood vessels, kidneys, and brain.
  • Rheumatoid arthritis: Causes pain and swelling, often in the wrists, hands, and feet.
  • Scleroderma: A rare disease affecting skin, blood vessels, and organs.
  • Sjögren's syndrome: Affects glands that produce tears and saliva.
  • Addison Disease: Affects the adrenal glands, causing fatigue and weakness.
  • Autoimmune hepatitis: Causes swelling in the liver.
  • Thyroid diseases: Affects thyroid hormone production.

Why do I need an ANA test?

Your provider may order this test if you have symptoms of an autoimmune disorder, such as:

  • Fever
  • Rash, blisters, or skin color changes
  • Fatigue
  • Joint pain, stiffness, and swelling
  • Muscle pain
  • Swollen glands
  • Abdominal pain

What happens during an ANA test?

A health care professional will take a blood sample from a vein in your arm using a small needle. The procedure usually takes less than five minutes.

Preparation and Risks

Preparation: Tell your provider about all medicines you take, as some may affect test results. Do not stop taking any medication unless instructed by your provider.

Risks: There is very little risk, though you may experience slight pain or bruising at the needle site.

What do the results mean?

An ANA test alone cannot diagnose a specific disease; it is used alongside other tests and clinical information.

  • Negative result: Antinuclear antibodies were not found. It is less likely you have an autoimmune disorder, though it does not rule it out completely.
  • Positive result: Antinuclear antibodies were found. This may indicate SLE, another autoimmune disease, a viral infection, or other health conditions like cancer.

Note that some healthy people, particularly women over 65, may have a positive ANA result. If your result is positive, your provider will likely order further testing.

Frequently Asked Questions

The titer indicates the concentration of the antibodies in your blood, usually expressed as a ratio (e.g., 1:40, 1:160). Higher titers generally suggest a higher likelihood of an autoimmune condition, though low titers can still be significant in certain contexts. The pattern describes how the antibodies bind to the cell nucleus under a microscope (e.g., homogeneous, speckled, or nucleolar). Different patterns are associated with different diseases; for example, a speckled pattern is often seen in systemic lupus erythematosus, while a nucleolar pattern may suggest scleroderma.
Yes, it is possible to have an autoimmune disease with a negative ANA test. While the test is highly sensitive for systemic lupus erythematosus, it is less sensitive for other conditions like rheumatoid arthritis or Sjögren's syndrome. Some patients with these conditions may have negative ANA results but positive results for other specific antibodies, such as rheumatoid factor or anti-CCP. Diagnosis relies on a combination of clinical symptoms and multiple laboratory tests.
No, a positive ANA test does not automatically confirm a diagnosis of an autoimmune disorder. Up to 15% of healthy individuals, particularly women, may have low levels of antinuclear antibodies without having any disease. Clinicians interpret the result based on the specific antibody pattern, the titer level, and your clinical symptoms. A positive result is often a starting point for further, more specific testing to identify the exact condition.
There is typically no special dietary preparation required, such as fasting, unless your provider orders additional blood tests that require it. However, you must disclose all medications, supplements, and herbal remedies you are taking. Certain drugs, such as procainamide, hydralazine, and isoniazid, can induce the production of antinuclear antibodies, leading to a false-positive result or masking the true cause of your symptoms.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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