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Ancaiggtitrserif

Published: August 9, 2026Updated: August 17, 2026

This blood test checks for antibodies that attack white blood cells, helping doctors diagnose certain types of blood vessel inflammation.

Quick summary

{"Measures IgG antibodies against neutrophils in your blood","Helps diagnose ANCA-associated vasculitis conditions","Results are reported as a titer (dilution ratio)","A positive result suggests autoimmune vessel inflammation","Results are interpreted alongside symptoms and other tests"}

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
29967-7
Short code
ANCAT
Synonyms
ANCA IgG Titr Ser IF
Category
chemistry
Sample
serum
Container
Serum separator tube (SST) - red-top or gold-top tube; alternatively plain red-top tube without anticoagulant
Units
N/A
Ref low
0
Ref high
1
Critical range
0.5 N/A – —
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
Indirect Immunofluorescence (IIF) using ethanol-fixed and formalin-fixed neutrophil substrates; serial dilution titer determination
CPT
86256
SNOMED
39527001
Specimen volume
1-2 mL serum (minimum 0.5 mL)
Stability
Serum stable for 7 days at 2-8°C; for extended storage, freeze at -20°C or below for up to 6 months. Avoid repeated freeze-thaw cycles.
Hemolysis max
100
Lipemia max
100
Icterus max
50
TAT
24–72 hours
Order
routine

What is this test?

The Neutrophil Cytoplasmic IgG Antibody (ANCA) test is a blood test that detects IgG antibodies directed against proteins in neutrophils (a type of white blood cell). These antibodies can attack the body's own blood vessels, causing inflammation. The test uses immunofluorescence technology to identify and measure these antibodies in your blood serum.

Why do I need this test?

Your doctor may order this test if you have symptoms suggesting vasculitis (blood vessel inflammation), such as persistent fever, unexplained weight loss, skin rashes, joint pain, kidney problems, or sinus/nasal issues. This test helps differentiate between different types of vasculitis and guides treatment decisions.

How is the test performed?

A healthcare professional will draw a blood sample from a vein in your arm. The blood is collected in a tube, allowed to clot, and then spun to separate the serum. The serum is then tested using immunofluorescence techniques to detect and measure ANCA antibodies. Results are typically reported as a titer (for example, 1:40) indicating the highest dilution at which antibodies can still be detected.

What do the results mean?

Results are reported as either negative or positive, with a titer value if positive. A positive result with high titer levels suggests ANCA-associated vasculitis. However, results must be interpreted alongside your clinical symptoms, physical examination, and other laboratory tests. Some infections or medications can also cause false-positive results.

Reference range

Negative: <1:10 (reported as no detectable ANCA). Positive results reported as the highest dilution showing detectable fluorescence pattern (c-ANCA, p-ANCA, or atypical). Endpoint titer reported with pattern interpretation.N/A

Specimen: serum

No fasting required. Patients should inform the laboratory of any current immunosuppressive therapy, as treatment may affect antibody titers. Avoid hemolyzed, lipemic, or contaminated specimens.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

Do I need to fast before this test?
No, you do not need to fast before this blood test. You can eat and drink normally unless your doctor gives you other instructions.
Are there any risks with this test?
The risks are minimal and include slight pain or bruising at the needle site, lightheadedness, and in rare cases, infection. These risks are similar to any standard blood draw.
Can medications affect my results?
Yes, certain medications such as immunosuppressants, hydralazine, minocycline, and antithyroid drugs may affect test results. Always inform your doctor about all medications and supplements you are taking.
How long does it take to get results?
Results are typically available within a few days to a week, depending on the laboratory. Your healthcare provider will contact you with the results.
What happens if my test is positive?
A positive test does not automatically mean you have vasculitis. Your doctor will evaluate the result along with your symptoms, physical examination, and other test results (such as kidney function tests) to make a diagnosis. Additional testing may be needed.
  1. 1
    Mayo Clinic - ANCA VasculitisSource
  2. 2
    National Institutes of Health - ANCA TestingSource
  3. 3
    American College of Rheumatology - VasculitisSource

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.

Medical Disclaimer

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