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Serum Proteinase 3 (PR3) Immunoassay

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

This test measures the level of antibodies against Proteinase 3 (PR3) in your blood. PR3 is a protein linked to a type of autoimmune condition called vasculitis.

Quick summary

["This test helps diagnose or monitor conditions affecting blood vessels and immune response."]

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

Key facts at a glance

LOINC
29644-2
Short code
Proteinase3 Ser Ql IA
Synonyms
Proteinase3 Ser Ql IA
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
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 Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like joint pain, skin rashes, or unexplained bleeding, which could be linked to vasculitis. It may also be used to assess active disease in patients already diagnosed with conditions like Wegener’s granulomatosis or microscopic polyangiitis.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm to draw blood. The process usually takes a few minutes. If you’re on blood thinners, let your provider know before the test.

What the Results Mean

Elevated levels of PR3 antibodies may indicate an active autoimmune condition affecting blood vessels. Your results will be compared to a standard reference range provided by your lab. Consult your healthcare provider for interpretation.

Common Conditions Linked to PR3 Antibodies

Positive results are most commonly associated with vasculitis, a group of rare diseases that cause inflammation in blood vessels. Conditions like Wegener’s granulomatosis and microscopic polyangiitis are often linked to high PR3 antibody levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

PR3 Antibody Test

Frequently asked questions

What symptoms might trigger this test?
Symptoms such as persistent joint pain, unexplained skin lesions, nosebleeds, or kidney issues (like protein in urine) may prompt this test. It helps differentiate vasculitis from other conditions.
How often should I get this test?
Your provider will determine the frequency based on your diagnosis, symptoms, and treatment plan. Regular monitoring may be needed if you have an ongoing autoimmune condition.
Can lifestyle changes affect PR3 antibody levels?
While lifestyle factors like diet and stress management may influence overall health, they don’t directly alter PR3 antibody levels. Your results depend on your immune system’s activity and disease state.
  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