An antineutrophil cytoplasmic antibodies (ANCA) test is a blood test that detects ANCAs in your blood. ANCAs are proteins made by the immune system that mistakenly target neutrophils, infection-fighting white blood cells. ANCA testing helps healthcare providers diagnose and monitor certain types of vasculitis and inflammatory bowel disease.
An ANCA test is a blood test that looks for antineutrophil cytoplasmic antibodies (ANCAs) in your blood.
ANCAs are a type of autoantibody. Autoantibodies are proteins made by your immune system that mistakenly target normal tissues. These particular autoantibodies target proteins inside neutrophils. Neutrophils are white blood cells that help your body fight infection.
ANCA testing can detect autoantibodies and measure the number of autoantibodies in your blood.
ANCA testing helps healthcare providers diagnose certain kinds of vasculitis. Vasculitis is a group of autoimmune disorders that causes inflammation (swelling) of the blood vessels.
The types of vasculitis associated with ANCA are:
Blood vessels transport blood between your heart and your organs and tissues. Blood vessel inflammation can cause serious health problems, including organ damage and aneurysm.
There are two main types of ANCA, and testing can determine whether you have one or both:
A healthcare provider, like a nurse, doctor or laboratory technician, takes the sample of blood. Then the sample is sent to a laboratory for testing.
At the lab, some of your blood sample is mixed with neutrophils on a slide. If the sample contains ANCAs, they will attach to the neutrophils. A special stain added to the slide helps the lab see this activity under a microscope. The cells have a certain pattern of fluorescence, which the lab can identify as cytoplasmic (cANCA) or perinuclear (pANCA).
A laboratory may use one or two types of ANCA testing:
ANCA testing doesn’t usually require any preparation.
Sometimes a blood test measures several things at once. Some tests require you to fast for eight to 12 hours. That means you shouldn’t eat or drink anything besides water. Your healthcare provider will give you specific instructions.
Collecting blood for the ANCA test takes only a few minutes. In an office, clinic or lab, a healthcare provider will:
Your healthcare provider may ask you to keep the bandage on for a few hours. You may also need to avoid exercise for a few hours after the blood test.
Blood tests are very safe and involve little risk. You may have a small bruise where the needle went into your skin. Rarely, the vein may swell. Warm compresses can help.
ANCA testing is performed at a special laboratory. Results may take several days to a week.
Your healthcare provider will talk to you about the test results and what they mean for you. If the results are negative, then you likely don’t have autoimmune vasculitis. If the results are positive, you may be diagnosed with autoimmune vasculitis.
Your healthcare provider may order additional tests, such as a biopsy or more bloodwork. And they’ll consider many other factors to make an accurate diagnosis.
A note from Cleveland Clinic
An antineutrophil cytoplasmic antibodies (ANCA) test is a blood test that helps healthcare providers diagnose certain kinds of autoimmune vasculitis. Your healthcare provider will explain why you need this test and what the results mean for you.
Last reviewed by a Cleveland Clinic medical professional on 03/11/2022.
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