Antineutrophil Cytoplasmic Antibodies (ANCA) Test
Reviewed
Also called: ANCA antibodies, cANCA, pANCA, cytoplasmic neutrophil antibodies, serum anticytoplasmic autoantibodies
This test looks for antineutrophil cytoplasmic antibodies (ANCA) in your blood. These antibodies attack healthy white blood cells and can be a sign of autoimmune vasculitis or inflammatory bowel disease (IBD).
Specimen: Blood sample from a vein in your arm
Why this test may be ordered
- To find out if you have autoimmune vasculitis and which type
- To monitor treatment for autoimmune vasculitis
- To help diagnose whether you have ulcerative colitis or Crohn's disease (types of IBD)
Preparation and collection
You usually don't need any special preparations. Your provider will let you know if you need to prepare if the test is done with other blood tests.
A health care professional will take a blood sample from a vein in your arm using a small needle. This usually takes less than five minutes.
There is very little risk to having 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 provider will consider your ANCA test results along with your symptoms and the results of other tests. Ask your provider to explain what your test results mean.
- Negative (no ANCAs found): Your symptoms probably aren't caused by autoimmune vasculitis. Limitation: A negative result does not completely rule out all forms of vasculitis or other conditions. Next step: Your provider will consider other possible causes for your symptoms.
- Positive (ANCAs found): This may mean you have autoimmune vasculitis. The type of ANCA (cANCA or pANCA) can help diagnose which type of vasculitis you have. Limitation: A positive result alone is not enough to confirm a diagnosis. You will often need other blood tests and a biopsy to confirm the diagnosis. Next step: Your provider may order additional tests, including a biopsy of a swollen blood vessel, to confirm the diagnosis.
- A positive ANCA test does not confirm autoimmune vasculitis; other tests and a biopsy are often needed.
- ANCA test results are not always an accurate way to measure how much disease you have when monitoring treatment.
- For IBD, if neither ANCA nor ASCA antibodies are found, you may still have IBD.
What to do next
If you have questions about your results, talk with your provider. Your provider will consider your ANCA test results along with your symptoms and the results of other tests.
- What do my ANCA test results mean for my health?
- Do I need any additional tests to confirm a diagnosis?
- What type of ANCA was found in my blood?
- How will my results affect my treatment plan?
- Should I be tested for ASCA antibodies if I have symptoms of IBD?
Evidence source
U.S. National Library of Medicine: Antineutrophil Cytoplasmic Antibodies (ANCA) Test