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Serum Immunoassay for Anti-Neutrophil Cytoplasmic Antibodies (ANCA) – Specific to Proteinase 3 (PR3)

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

This test measures antibodies in your blood that target a protein found in white blood cells called Proteinase 3. These antibodies may be linked to certain autoimmune conditions affecting blood vessels.

Quick summary

["This test helps diagnose or monitor inflammatory conditions linked to ANCA-related vasculitis."]

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

Key facts at a glance

LOINC
85964-5
Short code
S pneum Da 1 IgG 2:1 Ser-Rto
Synonyms
S pneum Da 1 IgG 2:1 Ser-Rto
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your doctor may order this test if you have symptoms like persistent rash, kidney problems, lung issues, or unexplained inflammation. It’s often used to check for conditions like Wegener’s granulomatosis or microscopic polyangiitis, which involve inflammation in small blood vessels.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample, usually drawn from your arm. If you’re on blood thinners, let your doctor know before the test to avoid unusual bleeding.

What the Test Results Mean

Positive results suggest a high likelihood of ANCA-related vasculitis, but further testing (like biopsy) is often needed to confirm the diagnosis. Negative results mean fewer antibodies were detected, but other conditions could still be causing your symptoms.

Common Conditions Linked to This Test

Positive results are most strongly associated with vasculitis affecting small blood vessels, such as Wegener’s granulomatosis or microscopic polyangiitis. It may also be linked to other autoimmune conditions like rheumatoid arthritis or certain types of lupus.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

PR3-ANCA (Serum)

Frequently asked questions

What does a positive result mean for my health?
A positive result strongly suggests ANCA-related vasculitis, but your doctor will likely order additional tests (like imaging or a biopsy) to confirm the diagnosis. Treatment may include medications to reduce inflammation and control symptoms.
Can I eat or drink anything before this test?
You can eat and drink normally unless your doctor specifies otherwise. No fasting is required for this blood test.
Will this test affect my medications?
This test itself won’t interact with your medications, but if you’re on blood thinners (e.g., warfarin), let your doctor know before the test to avoid excessive bleeding.
  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