Also Known As
ANCA Antibodies
c-ANCA
p-ANCA
Serine Protease 3
MPO
PR3
Anticytoplasmic Autoantibodies
3-ANCA
PR3-ANCA
MPO-ANCA
Formal Name
Antineutrophil Cytoplasmic Antibodies; Myeloperoxidase Antibodies; Proteinase 3 Antibodies
This article was last reviewed on
This article waslast modified on
23 May 2018.
At a Glance
Why Get Tested?

To test for certain autoimmune disorders, specifically small vessel vasculitities such as Granulomatosis with polyangitis (GPA formerly known as Wegners Granulomatosis (WG), microscopic polyangitis (MPA), Churg-Strauss Syndrome and a few others

When To Get Tested?

When your doctor thinks that you have symptoms, such as a vasculitic rash or respiratory/renal symptoms that may be due to a vascular autoimmune disorder; In patients who are known to have antineutrophil cytoplasmic antibodies (ANCA) associated small vessel vasculitis, ANCA measurement is sometimes used to monitor response to therapy

Sample Required?

A blood sample taken from a vein in your arm

Test Preparation Needed?

None

On average it takes 7 working days for the blood test results to come back from the hospital, depending on the exact tests requested. Some specialist test results may take longer, if samples have to be sent to a reference (specialist) laboratory. The X-ray & scan results may take longer. If you are registered to use the online services of your local practice, you will be able to access your results online.

If the doctor wants to see you about the result(s), you will be offered an appointment. If you are concerned about your test results, you will need to arrange an appointment with your doctor so that all relevant information including age, ethnicity, health history, signs and symptoms, laboratory and other procedures (radiology, endoscopy, etc.), can be considered.

Lab Tests Online-UK is an educational website designed to provide patients and carers with information on laboratory tests used in medical care. We are not a laboratory and are unable to comment on an individual's health and treatment.

Reference ranges are dependent on many factors, including patient age, gender, sample population, and test method, and numeric test results can have different meanings in different laboratories.

For these reasons, you will not find reference ranges for the majority of tests described on this web site. The lab report containing your test results should include the relevant reference range for your test(s). Please consult your doctor or the laboratory that performed the test(s) to obtain the reference range if you do not have the lab report.

For more information on reference ranges, please read Reference Ranges and What They Mean.

What is being tested?

Antineutrophil cytoplasmic antibodies (ANCA) are a group of autoantibodies produced when a person's immune system mistakenly targets and attacks its own neutrophil proteins. Two of the most commonly targeted proteins are myeloperoxidase (MPO) and proteinase 3 (PR3). This results in the production of antibodies to MPO and/or PR3. The ANCA blood test detects the presence or absence of these autoantibodies by looking at the pattern of fluorescence on a slide under a microscope.

Antineutrophil cytoplasmic antibodies may be present in a variety of autoimmune disorders that cause inflammation and damage to blood vessels, predominantly small blood vessels, throughout the body (systemic vasculitis). Vasculitis can cause tissue and organ damage due to the narrowing and obstruction of these small blood vessels and the subsequent loss of blood supply. It can also produce areas of weakness in blood vessel walls, known as aneurysms, which have the potential to rupture.

The symptoms experienced by a person with small vessel systemic vasculitis depend upon the degree of autoimmune activity and the parts of the body involved. Early in the disease process, symptoms are often nonspecific – they include fatigue, fever, weight loss, muscle aches, and night sweats. As the disorder progresses, vascular damage may affect the functioning of the kidneys, eyes, skin, lungs, and liver. This can cause a wide range of symptoms related to these organ systems.

PR3 antibodies are most frequently seen in Granulomatosis with polyangitis (GPA). MPO antibodies are most often associated with microscopic polyangitis but may also be seen in people with pauci-immune necrotising glomerulonephritis, Churg-Strauss syndrome, and GPA.For more about these conditions, visit the Vasculitis UK.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

Accordion Title
Common Questions
  • How is it used?

    An ANCA test is requested in order to evaluate someone who has symptoms that may be due to autoimmune vasculitis. It may be requested by itself or along with two other tests that are used to distinguish between different autoimmune disorders. These include:

    • MPO antibodies
    • PR3 antibodies

    Additional tests that may be performed to aid in a diagnosis include ESR (erythrocyte sedimentation rate) to check for inflammation, FBC (full blood count) to measure and evaluate white and red blood cells, complement levels to assess inflammation and creatinine to evaluate kidney function. Sometimes an ANCA test may be requested to monitor the response to therapy, follow the course of the disease, and/or to detect a relapse.

  • When is it requested?

    An ANCA test and/or tests for MPO and PR3 are requested when a person is suspected of having a systemic autoimmune vasculitis, especially when symptoms suggest Granulomatosis with polyangitis (GPA ) or microscopic polyangiitis. Early in the disease, symptoms may be vague or nonspecific, such as fever, fatigue, weight loss, muscle and/or joint aches, and night sweats.

    As the disease progresses, damage to small blood vessels throughout the body may cause signs and symptoms associated with complications involving various tissues and organs. A few examples include:

    • Eyes — red, itchy eyes or "pink eye" (conjunctivitis); problems with sight (blurry vision, loss of vision)
    • Ears — hearing loss
    • Nose — runny nose or other upper respiratory symptoms that do not go away
    • Skin — rashes and/or granulomas
    • Lungs — cough and/or difficulty breathing
    • Kidneys — abnormal amounts of protein in the urine

    Some laboratories will perform all three tests, ANCA, MPO and PR3, as a panel while others will perform MPO and PR3 only if an initial ANCA test is positive.

    Testing may also be performed periodically to monitor a person who has been diagnosed with an autoimmune vasculitis.

  • What does the test result mean?

    Results of ANCA tests must be interpreted carefully and take several factors into account. A doctor will consider clinical signs and symptoms and results of other types of tests such as imaging studies when determining a diagnosis.

    Positive ANCA, PR3, and/or MPO tests help to support a diagnosis of systemic autoimmune vasculitis and to distinguish between different types. However, to confirm a diagnosis, a biopsy of an affected site is most often required. Negative tests results make it less likely that a person's symptoms are due to an autoimmune vasculitis.

    Most often, ANCA tests are performed using indirect immunofluorescence microscopy. Serum samples are mixed with neutrophils to allow autoantibodies that may be present to react with the cells. The sample is put on a slide and treated with a fluorescent stain. The slide is then examined under a microscope and the resulting pattern noted.

    Several different ANCA patterns may be seen:

    • Perinuclear (p-ANCA) – most of the fluorescence occurs near the nucleus. About 90% of samples with a p-ANCA pattern will have MPO antibodies.
    • Cytoplasmic (c-ANCA) – the fluorescence occurs throughout the cytoplasm of the cell. About 85% of samples with a c-ANCA pattern will have PR3 antibodies.
    • Negative ANCA — very little or no fluorescence
    • Atypical p-ANCA — seen in many cases of ulcerative colitis as well as some patients with Crohn's disease and rheumatoid arthritis.

    If an ANCA test result is positive, then an additional test is performed to determine the amount of antibody present. This is called a titer. To determine the titer, a serum sample is diluted in steps and each dilution is tested for the presence of the antibody. The greatest dilution at which the antibody can be detected is the titer. For example, if a serum tests positive after being diluted 64-fold, the titer is 1:64. The higher the titer, the more antibody is present in the blood.

    In addition, tests that are specific for antibodies to MPO and PR3 may be performed:

    • A positive test for PR3 antibodies and a positive c-ANCA or p-ANCA are seen in more than 80% of patients with active GPA
    • A positive test for MPO antibodies and a positive p-ANCA are consistent with microscopic polyangitis, glomerulonephritis, Churg-Strauss syndrome, and Goodpasture's syndrome. MPO and p-ANCA may also be present non specifically in other autoimmune disorders, such as systemic lupus erythematosus, rheumatoid arthritis, and Sjögren syndrome.

    The following table shows results that may be seen in some vasculitis conditions.

    Condition % of patients with c-ANCA pattern (PR3 antibodies) % of patients with p-ANCA pattern (MPO antibodies)
    Granulomatosis with polyangitis (GPA) 90% in active disease, 60-70% no active disease Less than 10%
    Microscopic polyangiitis 30% 60%
    Churg-Strauss syndrome Rare 50-80%
    Polyarteritis nodosa Rare Rare

    ANCA levels can change over time and may sometimes be used in a general way to monitor disease activity and/or response to therapy.

  • Is there anything else I should know?

    In most cases, a biopsy of an affected blood vessel is necessary to confirm a diagnosis of autoimmune vasculitis.

  • Will my ANCA, PR3 and MPO autoantibodies ever go away?

    Levels may fluctuate, but once a person has developed an autoantibody, they will continue to have it.

  • Can the ANCA test be performed in my doctor's surgery?

    ANCA, MPO and PR3 tests require specialised equipment. Your sample will need to be sent to a clinical immunology laboratory that performs these tests.

  • Should everyone have an ANCA test done?

    ANCA testing is only necessary when a person has symptoms that suggest systemic vasculitis. Most people will never need to have an ANCA test performed.

  • Are there conditions other than vasculitis that can cause a positive ANCA?

    Yes, there are several. Some of these include rheumatoid arthritis, inflammatory bowel disease, certain drugs, and infections involving the heart (endocarditis) or the respiratory system. The presence of a positive ANCA in these diseases does not mean that the patient has small vessel vasculitis.

  • How many autoimmune disorders cause systemic vasculitis?

    There is quite a long list of autoimmune disorders that have been identified (see the Links tab for more on these). They are organised, with some overlap, by the size of the blood vessels that they affect – small, medium, or large.