HomeLab TestsAntineutrophil Cytoplasmic Antibodies (ANCA) Test
Back to Lab Tests
Antineutrophil Cytoplasmic Antibodies (ANCA) Test
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Lab Tests

Antineutrophil Cytoplasmic Antibodies (ANCA) Test

The ANCA test detects specific antibodies in the blood that can cause autoimmune vasculitis, a condition characterized by inflammation of the blood vessels.

Overview

The antineutrophil cytoplasmic antibodies (ANCA) test looks for specific proteins in your blood. While antibodies are normally produced by the immune system to fight foreign substances like bacteria, in autoimmune disease, they mistakenly attack healthy cells. ANCAs specifically target white blood cells called neutrophils.

This attack leads to autoimmune vasculitis, which causes inflammation and narrowing of the blood vessels. There are two main types of ANCA: pANCA and cANCA. Identifying which type is present helps providers diagnose the specific form of vasculitis or, in the case of pANCA, certain types of inflammatory bowel disease (IBD).

What is it used for?

ANCA testing is used to:

  • Diagnose and monitor autoimmune vasculitis, such as:
    • Granulomatosis with polyangiitis (GPA)
    • Microscopic polyangiitis (MPA)
    • Eosinophilic granulomatosis with polyangiitis (EGPA)
  • Distinguish between types of IBD, such as ulcerative colitis and Crohn's disease.

Why do I need an ANCA test?

You may need this test if you exhibit symptoms of vasculitis or IBD. Symptoms of vasculitis vary based on the affected organs but often include fatigue, fever, weight loss, and specific issues like vision changes, hearing loss, skin rashes, coughing up blood, or numbness. Symptoms of IBD include abdominal pain, diarrhea, fever, and blood in the stool.

What happens during the test?

A health care professional will take a blood sample from a vein in your arm using a small needle. The procedure is quick, typically taking less than five minutes. There are no special preparations required, though your provider may order this test alongside other blood work.

Understanding Results

  • Negative Result: No ANCAs were found, suggesting your symptoms are likely not caused by autoimmune vasculitis.
  • Positive Result: ANCAs were found. Your provider will use the specific type of ANCA detected to help identify the type of vasculitis. Further testing, such as a biopsy of a swollen blood vessel, is often required to confirm a diagnosis.
  • Monitoring: While used to monitor treatment, ANCA levels are not always a perfectly accurate measure of disease activity.
  • IBD Testing: If tested for IBD, results are often compared with an ASCA antibody test. Finding ANCA without ASCA may suggest ulcerative colitis, while finding ASCA without ANCA may suggest Crohn's disease.

Frequently Asked Questions

NCA testing is usually considered when a clinician suspects an autoimmune vasculitis because of a combination of systemic symptoms (fatigue, fever, weight loss) plus organ‑specific signs such as unexplained kidney dysfunction, sinus or ear problems, skin purpura, lung infiltrates, or peripheral neuropathy. Isolated fatigue or mild joint pain without any organ involvement rarely warrants ANCA testing; your doctor will first evaluate more common causes before ordering the test.
positive ANCA establishes a baseline. Serial ANCA measurements (usually every 3–6 months or when symptoms change) can help gauge disease activity—rising titers may precede a flare, while decreasing titers often accompany remission. However, clinical assessment remains paramount; some patients have stable disease despite persistent ANCA positivity, and others flare with low or unchanged titers. Treatment decisions are based on the overall clinical picture, not solely on ANCA levels.
Most laboratories report ANCA results within 3–7 business days after the blood draw. A positive c‑ANCA (cytoplasmic pattern) most often targets proteinase‑3 (PR3) and is strongly associated with granulomatosis with polyangiitis (GPA). A positive p‑ANCA (perinuclear pattern) usually targets myeloperoxidase (MPO) and is seen in microscopic polyangiitis (MPA), eosinophilic granulomatosis with polyangiitis (EGPA), and occasionally in ulcerative colitis or other inflammatory conditions. The pattern helps narrow the differential diagnosis but must be interpreted alongside clinical findings.
Yes. Certain drugs (e.g., propylthiouracil, hydralazine, minocycline) and chronic infections (e.g., hepatitis C, bacterial endocarditis) can induce ANCA positivity without true vasculitis. Low‑titer ANCA in the absence of compatible symptoms is often considered a false‑positive or an incidental finding. Your physician will review any recent medications or infections when interpreting the result.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

kontakt@hittavard.se

Ⓒ 2024. Alla rättigheter förbehålls av juxt ab

Sök
Om ossVillkor och policyVanliga frågorKontakta oss