Understanding Your Laboratory Test: What It Is, How It Is Done, and What Your Results Mean
This test detects autoantibodies (ANCA) in cerebrospinal fluid that may indicate autoimmune vasculitis affecting the nervous system.
{"The test checks for ANCA antibodies in the fluid surrounding your brain and spinal cord","It helps diagnose autoimmune conditions that cause blood vessel inflammation","A lumbar puncture (spinal tap) is required to collect the sample","Results are reported as titers (dilution levels)","Positive results suggest autoimmune vasculitis but require clinical correlation"}
Key facts at a glance
- LOINC
- 63293-5
- Short code
- ANCA-CSFT
- Synonyms
- ANCA Ab Titr CSF IF
- Category
- chemistry
- Sample
- csf
- Container
- Sterile, screw-cap, polypropylene CSF collection tube (tube 3 or 4 recommended to minimize blood contamination)
- Units
- N/A
- Ref low
- 0
- Ref high
- 1
- Critical range
- 0.5 N/A – —
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–99 years
- Method
- Indirect Immunofluorescence (IIF) using neutrophil substrates for titer determination
- CPT
- 86256 (ANCA titer)
- SNOMED
- 425646009 (Anti-neutrophil cytoplasmic antibody measurement)
- Specimen volume
- 1-2 mL of cerebrospinal fluid
- Stability
- Room temperature: 2 hours; Refrigerated (2-8°C): 24 hours; Frozen (-20°C or below): up to 1 month for delayed testing
- Hemolysis max
- 200
- TAT
- 24–96 hours
- Order
- routine
What is this test? This laboratory test helps your doctor evaluate your overall health, screen for certain medical conditions, or monitor a known diagnosis and how well your current treatment is working over time.
The Neutrophil Cytoplasmic Antibody (ANCA) test detects specific autoantibodies in your cerebrospinal fluid (CSF). These antibodies target proteins in neutrophils (a type of white blood cell). When present in the CSF, they may indicate that autoimmune inflammation is affecting the blood vessels in your brain or spinal cord.
How is the sample collected? A trained healthcare professional will draw a small sample, usually from a vein in your arm using a thin needle, and the collection process is quick, safe, and typically takes only a few minutes.
A lumbar puncture (spinal tap) is performed to collect CSF. The healthcare provider will insert a thin needle between two vertebrae in your lower back to withdraw fluid. The procedure takes about 15-30 minutes. You may experience mild discomfort or headache afterward.
What do the results mean? Your values are compared against standard reference ranges, and results outside those ranges may point to a condition that needs further attention; your doctor will interpret them alongside your symptoms, medications, and medical history before recommending any next steps.
Results are reported as titers, indicating the highest dilution of CSF that still shows antibody activity. A positive or elevated titer suggests the presence of ANCA-associated vasculitis. However, results must be interpreted alongside your symptoms, other tests, and clinical examination by your doctor.
Reference range
Negative: Titer <1:1 or undetectable; Positive titers reported as serial dilutions (e.g., 1:10, 1:20, 1:40, 1:80, 1:160 or higher) depending on staining pattern (c-ANCA/p-ANCA)N/A
No fasting required. Inform the ordering physician of any immunosuppressive medications, recent infections, or neurological symptoms. CSF collection is performed via lumbar puncture by a qualified healthcare professional.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test is primarily used to diagnose and monitor ANCA-associated vasculitis that may involve the central nervous system, such as granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), or eosinophilic granulomatosis with polyangiitis (EGPA). It helps differentiate autoimmune vasculitis from other conditions with similar symptoms like multiple sclerosis or infections.
Frequently asked questions
Do I need to fast before this test?
How long does it take to get results?
Is the lumbar puncture painful?
What conditions can cause a positive result?
Sources
- 1
- 2
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