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Serum or Plasma Anti-Neutrophil Cytoplasmic Antibody (ANCA) by Immunofluorescence

Published: August 9, 2026Updated: August 16, 2026

This test checks for antibodies that may indicate a rare but serious autoimmune condition affecting blood vessels, called vasculitis.

Quick summary

["The ANCA test helps doctors diagnose or monitor blood vessel diseases linked to immune system activity."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
6554-0
Short code
S pneum Ag Spt Ql IF
Synonyms
S pneum Ag Spt Ql IF
Category
coagulation
Sample
sputum
Container
Sterile sputum container
Units
N/A
Ref low
0.8
Ref high
1.2
Critical range
— – 5 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
CPT
85610
SNOMED
396252006
Specimen volume
3-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
TAT
4–24 hours
Order
routine

What This Test Measures

The ANCA test detects specific antibodies (antineutrophil cytoplasmic antibodies) found in the blood. These antibodies target proteins in white blood cells called neutrophils, which can damage blood vessels when overactive. The test uses immunofluorescence to identify these antibodies in your serum or plasma.

Why It’s Done

Your doctor may order this test if you have symptoms like skin rashes, joint pain, kidney problems, or unexplained infections that could suggest vasculitis. It’s also used to monitor treatment progress in people with known vasculitis.

Sample Collection and Preparation

A small blood sample is drawn from your arm. The blood is processed to separate serum or plasma, which is then tested for ANCA antibodies. This process typically takes a few minutes.

What to Expect Before the Test

No special preparation is needed, but inform your doctor about any medications, especially blood thinners, or recent infections that might affect results.

Reference range

INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A

Specimen: sputum

Inform your healthcare provider if you are taking blood thinners. No special preparation required.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

ANCA Test

Frequently asked questions

What does a positive ANCA test mean?
A positive ANCA test indicates the presence of antibodies that may signal vasculitis. However, not everyone with positive results will have active disease, and symptoms may not appear immediately. Your doctor will interpret results in the context of your symptoms and other tests.
Can ANCA test results change over time?
Yes, ANCA levels can fluctuate. Some people with vasculitis experience temporary changes in antibody levels as their condition improves or worsens. Regular follow-up testing may be needed to monitor progression or response to treatment.
Does this test require fasting?
No fasting is required for this test. However, if you’re taking medications that affect blood tests, always check with your healthcare provider before the test.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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 16, 2026. · Read our editorial policy