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Blood Test Tracker

p-ANCA (perinuclear) Titer

A microscope test for antibodies that make white blood cells glow around the nucleus. It is linked to vasculitis, ulcerative colitis and some autoimmune liver conditions.

AI-verified against cited sources. Awaiting expert reviewAlso called p-ANCA, pANCA, P-ANCALOINC 14278-6

What it is

Anti-neutrophil cytoplasmic antibodies (ANCA) are immune proteins that attach to substances inside neutrophils, a type of white blood cell. In this test a lab scientist looks at neutrophils on a slide under a microscope. A glow that hugs the nucleus is called the perinuclear pattern, or p-ANCA. It is often caused by antibodies to a protein called MPO, but other antibodies can make the same glow. The result is reported as negative, or as a titer, which shows how far your blood can be diluted and still glow.

Why it matters

A p-ANCA pattern with MPO antibodies is a feature of microscopic polyangiitis and eosinophilic granulomatosis with polyangiitis, which are types of vasculitis (inflamed blood vessels). The same pattern is also found in ulcerative colitis, some autoimmune liver conditions and some reactions to medicines, and not all of those involve MPO antibodies. That is why a positive p-ANCA is usually followed by an MPO antibody test. It is not a diagnosis by itself, and clinicians read it with symptoms and other tests.

If it’s high

A positive result means antibodies that stain around the nucleus of neutrophils were found. In the right clinical setting, and especially with MPO antibodies, this supports a type of vasculitis. The same glow also occurs in bowel and liver conditions and with some medicines, and some positive results do not match any specific disease.

Common causes

  • Ulcerative colitis, which is more often linked to ANCA than Crohn disease
  • Autoimmune liver conditions such as autoimmune hepatitis and primary sclerosing cholangitis, which often show an atypical p-ANCA pattern
  • Reactions to some medicines, including hydralazine, minocycline and propylthiouracil, or to cocaine mixed with levamisole
  • Other autoimmune conditions, such as drug-induced lupus
  • Antibodies that are not aimed at MPO or PR3, which can make a similar glow
  • ANCA-associated vasculitis, most often microscopic polyangiitis or eosinophilic granulomatosis with polyangiitis

What can help

  • Ask whether an MPO and PR3 antibody test should be done to confirm the result
  • Ask which other tests, such as kidney function, urine tests, liver tests or bowel evaluation, make sense for your symptoms
  • Ask whether any of your medicines could be linked to this result
  • Keep track of symptoms such as blood in the urine, a long-lasting stuffy or bloody nose, a cough that will not clear, or belly pain with diarrhea, and share them with your clinician

What can affect your result

  • Test type: the microscope test shows the glow pattern, while MPO and PR3 antibody tests find the exact target, and the two can disagree
  • Each lab's dilution series and cutoff, for example below 1:20 at ARUP, Quest and Labcorp and below 1:4 at Mayo
  • Medicines and bowel or liver conditions that can cause the pattern
  • Some labs report p-ANCA only when it is positive, and otherwise print "ANCA negative"
  • Antibodies other than MPO antibodies can also make a perinuclear glow, so labs usually confirm a positive result with MPO and PR3 antibody tests (Mayo, ARUP).
  • Labs use different dilution series and cutoffs: ARUP, Quest and Labcorp call a titer below 1:20 negative, while Mayo Clinic Laboratories calls a titer below 1:4 negative.
  • ARUP runs the slides on both ethanol-fixed and formalin-fixed neutrophils to tell perinuclear from cytoplasmic patterns.
  • Samples with gross hemolysis, lipemia or bacterial contamination can be rejected by the lab (Labcorp).

Titers can change with treatment, but Mayo Clinic Laboratories suggests MPO or PR3 antibody tests, not the microscope titer, for following disease activity.

When to talk to a clinician

If your lab or clinician has not already contacted you about a positive result, call the clinician who ordered the test soon. Talk with a clinician promptly about blood or foam in your urine, a cough that will not go away, a long-lasting bloody or crusted nose, new numbness or weakness, or ongoing belly pain with diarrhea. Call 911 or your local emergency number if you cough up blood or have severe trouble breathing.

Questions you could ask

  • Is the microscope titer or the MPO antibody test better for following me over time?
  • Should an MPO and PR3 antibody test be done to confirm this?
  • Could a bowel or liver condition, or a medicine, explain this result?
  • Do my symptoms mean I should have kidney or urine tests?

Questions people ask

What is the difference between p-ANCA and MPO-ANCA?

p-ANCA is the glow pattern seen under a microscope. MPO-ANCA is a blood test that finds the specific protein (MPO) the antibody attaches to. Most p-ANCA patterns in vasculitis come from MPO antibodies, but other antibodies can cause the same pattern, so labs often run both.

Does a positive p-ANCA mean I have vasculitis?

No, not by itself. A p-ANCA pattern also occurs in ulcerative colitis, some liver conditions and with some medicines. Your clinician looks at your symptoms and other tests, including MPO antibodies.

Why does my report just say ANCA negative, with no titer?

Some labs report a p-ANCA or c-ANCA result only when it is positive. Otherwise the report simply says ANCA negative.

Show the science and sources

For clinicians and researchers

p-ANCA is the perinuclear staining pattern of IgG antibodies on ethanol-fixed neutrophils in indirect immunofluorescence (IIF). Mayo explains that anti-MPO antibodies produce the perinuclear pattern because of an artefact of the fixation process, whereas anti-PR3 antibodies give a granular cytoplasmic (c-ANCA) pattern. ARUP reports that about 90% of people with a p-ANCA pattern by IFA have MPO-specific antibodies (Labcorp states at least 60%). Other antigens can give a perinuclear pattern (Quest notes that people with bowel disease have antibodies that give a p-ANCA or c-ANCA pattern but may not be directed at MPO), and Mayo notes that a positive or indeterminate p-ANCA or c-ANCA without a detectable PR3 or MPO antibody may reflect an antibody of unidentified specificity. Atypical p-ANCA is reported in primary sclerosing cholangitis and autoimmune hepatitis (Terjung and Spengler 2009), and the 2003 consensus addendum includes recommendations for ANCA testing in inflammatory bowel disease. The 2017 revised international consensus (Bossuyt et al.) proposes that high-quality PR3 and MPO immunoassays can be the primary screen for GPA and MPA without a categorical need for IIF, and the EUVAS study found large differences between two IIF methods (AUC 0.923 and 0.843) compared with most immunoassays (AUC 0.936 to 0.959). Mayo advises that a positive ANCA IIF ordered as a stand-alone test should be confirmed with PR3 and MPO solid-phase immunoassays. ARUP's IFA is run on ethanol-fixed and formalin-fixed neutrophils to separate C- and P-ANCA patterns, reports a titer (reference below 1:20) and a pattern ('none detected'), and notes that ANCA is found in over 90% of people with certain necrotizing vasculitides and usually in under 5% of people with collagen vascular disease or arthritis. Reference cutoffs: ARUP, Quest and Labcorp below 1:20, Mayo below 1:4. In the 2022 ACR/EULAR classification criteria, p-ANCA or anti-MPO positivity scores +6 for MPA and -1 for GPA.

LOINC 14278-6 (primary), 32787-4, 17357-5, 30539-1. Specimen: serum.

Sources

  1. Anti-Neutrophil Cytoplasmic Antibody, IgG by IFA (test 3003747), ARUP Laboratories
  2. Myeloperoxidase (MPO) Antibody and Serine Proteinase 3 (PR3) Antibody with Reflex to Anti-Neutrophil Cytoplasmic Antibody, IgG by IFA (test 3003746), ARUP Laboratories
  3. ANCA Screen with Reflex to ANCA Titer (test 70171), Quest Diagnostics
  4. Antineutrophil Cytoplasmic Antibodies (ANCA) (test 162388), Labcorp
  5. Cytoplasmic Neutrophil Antibodies, Serum (test ANCA), Mayo Clinic Laboratories
  6. Position paper: Revised 2017 international consensus on testing of ANCAs in granulomatosis with polyangiitis and microscopic polyangiitis, Nature Reviews Rheumatology (2017)
  7. Detection of antineutrophil cytoplasmic antibodies (ANCAs): a multicentre European Vasculitis Study Group (EUVAS) evaluation of the value of indirect immunofluorescence (IIF) versus antigen-specific immunoassays, Annals of the Rheumatic Diseases (2017)
  8. 2022 American College of Rheumatology/European Alliance of Associations for Rheumatology classification criteria for microscopic polyangiitis, Annals of the Rheumatic Diseases (ACR/EULAR) (2022)
  9. Addendum to the International Consensus Statement on testing and reporting of antineutrophil cytoplasmic antibodies. Quality control guidelines, comments, and recommendations for testing in other autoimmune diseases, American Journal of Clinical Pathology (2003)
  10. Atypical p-ANCA in PSC and AIH: a hint toward a "leaky gut"?, Clinical Reviews in Allergy & Immunology (2009)
  11. Trojan horses: drug culprits associated with antineutrophil cytoplasmic autoantibody (ANCA) vasculitis, Current Opinion in Rheumatology (2014)
  12. Antineutrophil Cytoplasmic Antibodies (ANCA) Test, MedlinePlus (U.S. National Library of Medicine)

AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.

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