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
Autoantibody testing checks a sample of your blood for autoantibodies, proteins made by the immune system.
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
You don't need any special preparations for autoantibody testing.
A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.
There is very little risk to a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.
Understanding results
Your results may depend on the type of autoantibody test you had. But generally, your results will be either positive or negative.
- Negative (normal): A negative (normal) result means that you have little or no autoantibodies in your blood. Limitation: But that doesn't rule out an autoimmune disease. People with rheumatoid arthritis, for example, may have little to no RF in their blood. Next step: If you have symptoms of an autoimmune disease, but your results are normal, your provider may order more tests to make a diagnosis.
- Positive (abnormal): A positive (abnormal) result means that some amount of autoantibodies were found in your blood. Limitation: This doesn't necessarily mean that you have an autoimmune disease. Some healthy people have autoantibodies in their blood. Next step: To make a diagnosis, your provider will consider other test results along with your symptoms and medical history.
- Titer higher than the reference range: a titer value that is higher than the reference range may be a sign of an autoimmune disease. Limitation: This doesn't necessarily mean that you have an autoimmune disease. Next step: Because autoantibody test results can mean so many different things, it's important to talk to your provider about what your results mean for you.
- 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
Because autoantibody test results can mean so many different things, it's important to talk to your provider about what your results mean for you.
- 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?
Evidence source
Source: U.S. National Library of Medicine (MedlinePlus). Practices and reference ranges may differ in your country.