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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 specific protein found in white blood cells, called Proteinase 3. These antibodies are linked to certain types of autoimmune conditions affecting blood vessels.

Quick summary

["This test helps diagnose or monitor conditions like vasculitis, where inflammation damages blood vessels."]

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

Key facts at a glance

LOINC
86104-7
Short code
S pneum Da 10A IgG 2:1 Ser-Rto
Synonyms
S pneum Da 10A 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

What Is PR3-ANCA Used For?

PR3-ANCA is primarily used to identify people at risk for **vasculitis**, a group of rare conditions where inflammation causes blood vessels to become damaged. It may also help determine the cause of unexplained symptoms like joint pain, skin rashes, or organ damage.

How Is This Test Performed?

A blood sample is drawn from a vein in your arm. The sample is sent to a lab where it undergoes an immunoassay to detect PR3-ANCA antibodies. Results are reported as either **positive or negative** (no numeric range provided).

What Might Trigger a Positive Result?

A positive PR3-ANCA result often suggests **granulomatosis with polyangiitis (Wegener’s granulomatosis)**, a type of vasculitis affecting the nose, lungs, and kidneys. Other conditions (like microscopic polyangiitis) may also show positive results, but further testing is needed for diagnosis.

What Should You Expect After Testing?

If your test is positive, your doctor may order additional tests (like kidney function checks or imaging) to confirm the diagnosis and guide treatment. Follow-up tests may be needed to monitor your condition over time.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

PR3-ANCA (Anti-Proteinase 3 Antibody)

Frequently asked questions

Why was I asked to have this test?
Your doctor may recommend this test if you have symptoms like persistent sinus or lung infections, unexplained skin rashes, kidney problems, or unexplained joint pain. It helps identify whether your symptoms could be linked to vasculitis.
What does a positive result mean?
A positive result suggests you may have antibodies targeting Proteinase 3, which could indicate a condition like granulomatosis with polyangiitis. This does not confirm a diagnosis alone—further testing is needed to assess your health and treatment options.
Can I eat or drink before this test?
You may eat and drink normally before this test unless instructed otherwise. No special preparation is required, but avoid alcohol for 24 hours if your doctor advises it.
  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