Understanding Your Laboratory Test: What It Is, How It Is Done, and What Your Results Mean
This blood test detects antibodies that attack white blood cells, helping diagnose certain autoimmune diseases affecting blood vessels.
{"The test identifies antibodies (p-ANCA and c-ANCA) that mistakenly target white blood cells","It primarily helps diagnose vasculitis and inflammatory bowel diseases","A blood sample is drawn from a vein in your arm","Results help doctors distinguish between different types of autoimmune conditions","Positive results require clinical correlation with symptoms"}
Key facts at a glance
- LOINC
- 87427-1
- Short code
- ANCAPAN
- Synonyms
- ANCA Pnl Ser IF
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) or red-top tube (no anticoagulant)
- Units
- N/A
- Critical range
- 0.5 N/A – —
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Indirect Immunofluorescence Assay (IFA) using ethanol- and formalin-fixed neutrophil substrates
- CPT
- 86255
- SNOMED
- 39579001
- Specimen volume
- 1-2 mL of serum (minimum 0.5 mL)
- Stability
- Room temperature: 8 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 100
- Lipemia max
- 200
- Icterus max
- 40
- TAT
- 24–72 hours
- Order
- routine
What is this test, what does it measure, and why has my healthcare provider ordered it as part of my care?
The Neutrophil Cytoplasmic Antibody (ANCA) test is a blood test that detects specific antibodies in your blood. These antibodies (called antineutrophil cytoplasmic antibodies) are proteins that your immune system mistakenly produces against your own white blood cells called neutrophils. The test uses a technique called immunofluorescence to visualize and identify these antibodies.
How is the test performed, what happens during the procedure, and will it cause pain or take a long time?
A healthcare professional will draw a small blood sample from a vein in your arm using a needle. The blood is collected into a tube and sent to a laboratory for analysis. In the lab, technicians use special fluorescent dyes and microscopes to detect the presence and pattern of ANCA antibodies. There are two main patterns: c-ANCA (cytoplasmic) and p-ANCA (perinuclear), each associated with different conditions.
Why might I need this test, and what symptoms or health conditions could lead my doctor to recommend it?
Your doctor may order this test if you have symptoms suggesting an autoimmune disease, such as unexplained fever, joint pain, skin rashes, kidney problems, or respiratory symptoms. It is most commonly used to help diagnose conditions like granulomatosis with polyangiitis, microscopic polyangiitis, and other forms of vasculitis (blood vessel inflammation). It may also be used to monitor disease activity in patients already diagnosed with these conditions.
What do the results mean, and how will my doctor use normal or abnormal findings to guide my treatment?
Results are typically reported as positive or negative for ANCA antibodies. A positive result with c-ANCA pattern is strongly associated with granulomatosis with polyangiitis. A positive p-ANCA pattern may be seen in microscopic polyangiitis, ulcerative colitis, or primary sclerosing cholangitis. However, a positive test alone does not confirm a diagnosis—your doctor will interpret results alongside your symptoms, physical exam, and other test results.
Reference range
Negative: No fluorescence pattern detected at screening dilution (typically 1:20). Positive results are reported with titer and pattern (c-ANCA, p-ANCA, or atypical ANCA). Titers ≥1:20 generally considered positive.N/A
No special patient preparation required. Fasting is not necessary. Patient should be informed about the test purpose. Recent immunosuppressive therapy may affect antibody titers; document current medications.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
The ANCA test is primarily used to diagnose and monitor autoimmune vasculitis, including granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). It helps distinguish between different types of vasculitis, which is important because treatment approaches vary. The test can also aid in diagnosing inflammatory bowel diseases like ulcerative colitis and primary sclerosing cholangitis. In patients already diagnosed with these conditions, serial ANCA testing may help track disease activity and response to treatment.
Frequently asked questions
Do I need to fast before this test?
Are there any risks or side effects?
How long does it take to get results?
Can this test diagnose my condition definitively?
Do healthy people ever have positive ANCA results?
Sources
- 1Mayo Clinic - ANCA testSource
- 2
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy