Medically Reviewed by: Dr. Dipak Ladda, M.D.
Expertise: Consultant Pathologist
Last Updated: August 5, 2026
Medical Analysis
Comprehensive Clinical Evaluation, Pathophysiology, and Diagnostic Strategies for C-ANCA Antibody Testing
C-ANCA
Here, IgG class ANCA are directed against proteinase 3 (PR3) of neutrophils and monocytes [10]. It is responsible for vascular damage by causing excessive neutrophil activation and vessel wall destruction [11]. The presence of PR3 ANCA is a specific diagnostic indicator of Wegener Granulomatosis [6]; less than 2% of positive results occur in patients who do not have the disease [6]. ANCAs are a type of autoantibodies; which are proteins made by immune system that mistakenly target normal tissues [3]. These particular autoantibodies target proteins inside neutrophils [10]. This can lead to a disorder called autoimmune vasculitis [1]. The ANCA associated vasculitides (AAV) are a collection of relatively rare autoimmune diseases of unknown cause, characterised by inflammatory cell infiltration causing necrosis of blood vessels [1].
Pathophysiology
We are describing both pANCA and cANCA under one umbrella i.e. Autoimmune vasculitis; which cause inflammation & swelling in blood vessels that leads to narrowing of blood vessels [1]. Depending upon affected blood vessels; further problems get created [1]. There are two main kinds of ANCA called PANCA & CANCA [2]. Each type targets a specific protein inside white blood cells [2]. CANCA: Targets a protein called proteinase 3 (PR3) [10]. PANCA: Targets a protein called myeloperoxidase (MPO) [2]. This information helps to diagnose which type of autoimmune vasculitis is there [2]. For e.g. – Testing for pANCA help in diagnosis of inflammatory bowel disease [2].
ANCA Antibody test
This test detects antineutrophil cytoplasmic antibodies (ANCA) in a blood sample [4]. ANCA testing helps in diagnosis and monitor certain types of vasculitis and inflammatory bowel disease [4].
Indications
To diagnose and monitor treatment of autoimmune vasculitis [12]. To diagnose ulcerative colitis or Crohn’s disease [2]. To find out autoimmune vasculitis and it’s type [1]. Types includes – Granulomatosis with polyangiitis (GPA) [6]. Microscopic polyangiitis (MPA) [2]. Eosinophilic granulomatosis with polyangiitis (EGPA) [15]. General symptoms may includes: Fatigue, Fever, General aches and pains, Loss of appetite, Weight loss [1].
Methods Of Estimation
Semi-Quantitative Indirect Fluorescent Antibody (IFA) [9]. Indirect immunofluorescence (IIF) [9]. Enzyme-linked immunosorbent assay (ELISA) [8]. Comprehensive panel for the evaluation of ANCA associated vasculitis [4]. First-line panel : Myeloperoxidase (MPO) Antibody, Serine Proteinase 3 (PR3) Antibody with Reflex to Anti-Neutrophil Cytoplasmic Antibody, IgG by IFA [4]. For evaluation of autoimmune liver disease, use in conjunction with Autoimmune Liver Disease Reflexive Panel [13].
Before Sample Collection
No special preparation is required for a PANCA blood test [4].
Sample Collection
Sample:- Blood sample: Collect 3.0 ml blood in plain tube (Red capped) [4]. Separate serum as early as possible & send it to lab [4].
Reference Range of Panel Components
| Components | Reference Range |
| Myeloperoxidase (MPO) Ab, IgG | 19 AU/mL or less [2] |
| Serine Proteinase 3 (PR3) Ab, IgG | 19 AU/mL or less [10] |
| ANCA IFA Pattern | None Detected [9] |
| ANCA IFA Titer | Less than 1:20 [9] |
MPO & PR3 Antibodies – Reference Ranges
| Components | Reference Range | Interpretation |
| Myeloperoxidase (MPO) Antibody | 19 AU/mL or less [2] | Negative [2] |
| Myeloperoxidase (MPO) Antibody | 20-25 AU/mL [2] | Equivocal [2] |
| Myeloperoxidase (MPO) Antibody | 26 AU/mL or greater [2] | Positive [2] |
| Serine Proteinase 3 (PR3) Antibody | 19 AU/mL or less [10] | Negative [10] |
| Serine Proteinase 3 (PR3) Antibody | 20-25 AU/mL [10] | Equivocal [10] |
| Serine Proteinase 3 (PR3) Antibody | 26 AU/mL or greater [10] | Positive [10] |
Associated Diseases
| Disease | CANCA Association | Key Notes |
| Granulomatosis with Polyangiitis (GPA) | Strongly positive (90-95%) [6] | Formerly known as Wegener’s granulomatosis; PR3-ANCA predominant [6, 10] |
| Microscopic Polyangiitis (MPA) | Variable, ~50% CANCA positive [2] | More often MPO-ANCA positive; CANCA less frequent [2] |
| Eosinophilic Granulomatosis with Polyangiitis (EGPA) | 30-40% positive, mostly MPO-ANCA [15] | Possible CANCA positivity Associated with asthma and eosinophilia [15] |
| Drug-Induced Vasculitis | Associated with medications like propylthiouracil [18] | |
| Renal-Limited Vasculitis | Variable CANCA positivity [2] | Vasculitis mainly confined to kidneys [2] |
PANCA & CANCA: Comparison
| Feature | PANCA (Perinuclear ANCA) | CANCA (Cytoplasmic ANCA) |
| Major Antigen Target | Myeloperoxidase (MPO) [2] | Proteinase 3 (PR3) [10] |
| Main Associated Disease | Microscopic Polyangiitis (MPA), EGPA, Ulcerative Colitis [2] | Polyangiitis (GPA; Wegener’s) [6, 10] |
| Typical Organs Involved | Kidney, lung, skin [1] | ENT, lung, kidney [6] |
| IIF Staining Pattern | Perinuclear [9] | Cytoplasmic [9] |
| Diagnostic Specificity | ↑MPA, EGPA, some autoimmune diseases [2] | ↑GPA [6] |
| Other Associations | PSC, autoimmune hepatitis, drug-induced vasculitis [13, 18] | Rarely seen outside GPA [6] |
| Clinical Notes | More frequent in non-GPA vasculitis [2] | Highly specific for GPA [6] |
Limitations
Results of this assay are not diagnostic proof of the presence or absence of disease and should be used in conjunction with clinical findings [7]. Lack of specificity [7]. Infections and other autoimmune conditions may give false positivity [7].
For Non-Medicos
Understanding ANCA Blood Tests and Vasculitis
ANCA blood tests look for specific autoantibodies that mistakenly attack proteins inside white blood cells, causing inflammation and damage to your blood vessels known as autoimmune vasculitis [1, 3].
Sample Collection, Results, and Patient Care
To complete this assessment, a quick blood sample is drawn into a red-capped tube with no special preparation needed beforehand [4]. Doctors use these lab findings alongside your symptoms—such as fever, fatigue, and weight loss—to guide accurate diagnoses and monitor ongoing treatments [1, 12].
References:
Jennette, J. C., & Falk, R. J. (1997). Small-vessel vasculitis. New England Journal of Medicine, 337(21), 1512-1523.
Falk, R. J., & Jennette, J. C. (1988). Anti-neutrophil cytoplasmic autoantibodies with specificity for myeloperoxidase in patients with systemic vasculitis and idiopathic necrotizing and crescentic glomerulonephritis. New England Journal of Medicine, 318(25), 1651-1657.
Kallenberg, C. G., Mulder, A. H., & Cohen Tervaert, J. W. (1992). Antineutrophil cytoplasmic antibodies: a still-growing class of autoantibodies in inflammatory and autoimmune diseases. American Journal of Medicine, 93(6), 675-682.
Savige, J., Gillis, D., Benson, E., Davies, D., Esdale, J., Hall, F., … & Wiik, A. (1999). International consensus statement on testing and reporting of antineutrophil cytoplasmic antibodies (ANCA). American Journal of Clinical Pathology, 111(4), 507-513.
Gross, W. L., Csernok, E., & Helmchen, U. (1993). Antineutrophil cytoplasmic antibodies, autoantigens, and systemic vasculitis. World Journal of Surgery, 17(2), 172-180.
Niles, J. L., McCluskey, R. T., Ahmad, M. F., & Arnaout, M. A. (1989). Wegener’s granulomatosis, systemic vasculitis, and renal disease. Annals of Internal Medicine, 111(8), 655-659.
Rao, J. K., Allen, N. B., & Pincus, T. (1995). Limitations of antineutrophil cytoplasmic antibodies (ANCAs) in the diagnosis of primary systemic vasculitis. Annals of Internal Medicine, 123(8), 579-584.
Hagen, E. C., Daha, M. R., & van der Woude, F. J. (1998). Diagnostic value of standardized assays for anti-neutrophil cytoplasmic antibodies in systemic vasculitis. Kidney International, 53(3), 743-753.
Wiik, A. (1989). Delineation of a standard method for indirect immunofluorescence detection of ANCA. APMIS, 97(1-6), 12-13.
Goldschmeding, R., van der Schoot, C. E., ten Bokkel Huinink, D., Hack, C. E., Spaargaren, M., & von dem Borne, A. E. (1989). Wegener’s granulomatosis autoantibodies identify a novel diisopropylfluorophosphate-binding protein in the lysosomes of normal human neutrophils. Journal of Clinical Investigation, 84(5), 1577-1587.
Falk, R. J., Terrell, R. S., Charles, L. A., & Jennette, J. C. (1990). Anti-neutrophil cytoplasmic autoantibodies induce neutrophils to degranulate and produce oxygen radicals in vitro. Proceedings of the National Academy of Sciences, 87(11), 4115-4119.
Cohen Tervaert, J. W., Mulder, A. H., & Kallenberg, C. G. (1990). The role of antineutrophil cytoplasmic antibodies (ANCA) in the management of patients with Wegener’s granulomatosis. Clinical and Experimental Rheumatology, 8(6), 569-574.
Wiik, A. (2003). Autoantibodies in vasculitis. Arthritis Research & Therapy, 5(3), 156-161.
Radice, A., & Sinico, R. A. (2005). Antineutrophil cytoplasmic antibodies (ANCA). Autoimmunity, 38(1), 93-103.
Choi, H. K., & Merkel, P. A. (2002). Diagnostic test performance of antineutrophil cytoplasmic antibodies in polyarteritis nodosa and Churg-Strauss syndrome. Arthritis & Rheumatism, 46(6), 1601-1607.
Jennette, J. C., & Falk, R. J. (2005). Pathogenesis of antineutrophil cytoplasmic autoantibody-associated small-vessel vasculitis. Current Opinion in Rheumatology, 17(1), 9-14.
Csernok, E., & Gross, W. L. (1999). Antineutrophil cytoplasmic antibodies (ANCA): target antigens and assay methods. Autoimmunity Reviews, 1(1), 30-34.
Stone, J. H., Merkel, P. A., Spiera, R., Seo, P., Langford, C. A., Hoffman, G. S., … & WACS Investigators. (2010). Rituximab versus cyclophosphamide for ANCA-associated vasculitis. New England Journal of Medicine, 363(3), 221-232.
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FAQ’s:
What is C-ANCA?
IgG antibodies directed against proteinase 3 of neutrophils causing vascular damage and Wegener Granulomatosis.What are ANCAs?
Autoantibodies produced by the immune system that mistakenly target normal tissues and proteins inside neutrophils.What does ANCA testing diagnose?
It helps diagnose and monitor autoimmune vasculitis, inflammatory bowel disease, Crohn’s disease, and ulcerative colitis.What are common symptoms?
General signs include fatigue, fever, general aches and pains, loss of appetite, and weight loss.What methods estimate antibodies?
Estimations use semi-quantitative indirect fluorescent antibody, indirect immunofluorescence, and enzyme-linked immunosorbent assay methods.How is blood collected?
Collect 3.0 ml of blood in a plain red-capped tube and separate serum early for the lab.What is MPO reference range?
Myelopheroxidase antibody levels of 19 AU/mL or less are negative, and 26 AU/mL or greater are positive.What is PR3 reference range?
Serine proteinase 3 antibody levels of 19 AU/mL or less are negative, and 26 AU/mL or greater are positive.How does GPA associate?
Granulomatosis with polyangiitis is strongly positive for C-ANCA at 90 to 95 percent and strongly associated.
Are results absolute proof?
No, assay results are not diagnostic proof and must be used with clinical findings and patient context.
