autoantibody-testing
Reviewed
Also called: antibody serology test, antinuclear antibody (ANA) test, extractable nuclear antigen (ENA) test, anti-dsDNA test, rheumatoid factor (RF) test, antineutrophil cytoplasmic antibodies (ANCA) test
This test checks a sample of your blood for autoantibodies—proteins made by your immune system that mistakenly attack your own healthy tissues. It helps diagnose or monitor autoimmune diseases, but results alone are usually not enough to make a diagnosis.
Specimen: blood
Why this test may be ordered
- You have symptoms that could be from an autoimmune disease, such as fever, fatigue, joint pain or swelling, muscle pain or weakness, swollen glands, unexplained rash, or unexpected weight changes.
- You have been diagnosed with an autoimmune disease and your provider wants to monitor your condition.
Preparation and collection
No special preparation is needed.
A health care professional will take a blood sample from a vein in your arm. You may feel a brief sting, and the process usually takes less than five minutes.
There is very little risk to a blood test. You may have slight pain or bruising at the needle site, but most symptoms go away quickly.
Understanding results
Your results depend on the type of autoantibody test you had. Generally, results are either positive or negative. Some results may give a number (titer) with a reference range. Because results can mean many different things, it is important to talk to your provider about what your results mean for you.
- Negative (normal): Little or no autoantibodies were found in your blood. This does not rule out an autoimmune disease. For example, people with rheumatoid arthritis may have little to no rheumatoid factor in their blood. If you have symptoms, your provider may order more tests. Limitation: A negative result does not exclude an autoimmune disease. Next step: Your provider may order additional tests to help make a diagnosis.
- Positive (abnormal): Some amount of autoantibodies were found in your blood. This does not necessarily mean you have an autoimmune disease—some healthy people have autoantibodies. Your provider will consider other test results, your symptoms, and your medical history. Limitation: A positive result alone is not enough to diagnose an autoimmune disease. Next step: Your provider will interpret this result along with other information to determine if you have an autoimmune condition.
- Titer value higher than the reference range: A higher level of autoantibodies may be a sign of an autoimmune disease. Limitation: The reference range is a set of numbers that form the high and low ends of what is considered normal. A value above that range may be significant, but it must be interpreted by your provider. Next step: Your provider will discuss what the titer means in your specific situation.
- Panel results (e.g., ANA, ENA) with mixed findings: You may have positive results for some autoantibodies and negative results for others. This pattern can help your provider narrow down possible autoimmune conditions. Limitation: Results from autoantibody panels can be complex and require expert interpretation. Next step: Your provider will explain what each result means and how it fits with your overall picture.
- A negative result does not rule out an autoimmune disease.
- A positive result does not necessarily mean you have an autoimmune disease—some healthy people have autoantibodies.
- Results alone are usually not enough to make a diagnosis; your provider will also consider imaging, biopsy, symptoms, and family/health history.
What to do next
Talk to your provider about what your results mean for you. They may order additional tests or refer you to a specialist.
- What type of autoantibody test did I have?
- What do my results mean in my specific situation?
- Do I need any follow-up tests or appointments?