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Anti-Proteinase 3 Antibody (ANCA-P3) - Serum

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

This test measures the presence of antibodies against Proteinase 3, a protein found in certain white blood cells. These antibodies are linked to a type of autoimmune condition called vasculitis.

Quick summary

["This test helps diagnose or monitor a specific type of inflammation in blood vessels."]

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

Key facts at a glance

LOINC
82433-4
Short code
Deprecated Proteinase3 Ab Ser Ql IB
Synonyms
Deprecated Proteinase3 Ab Ser Ql IB
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ib
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 This Test Measuring?

Proteinase 3 is an enzyme produced by neutrophils, a type of white blood cell. When the immune system mistakenly attacks this protein, it can lead to inflammation in small blood vessels. The test detects antibodies (immune proteins) that target Proteinase 3, which are associated with a condition called **c-ANCA vasculitis** (a subtype of vasculitis).

Why Might This Test Be Ordered?

Your healthcare provider may recommend this test if you have symptoms like skin rashes, joint pain, kidney issues, or unexplained infections. It is often used to confirm a diagnosis of vasculitis or to monitor disease activity in patients already diagnosed with this condition.

How Is the Sample Collected?

A small amount of blood is drawn from a vein in your arm. The blood is processed into serum (the liquid part after clotting) for testing.

What Are Possible Results?

Results are qualitative (positive or negative) and indicate whether antibodies are present. A positive result suggests a higher likelihood of vasculitis, but it is not definitive on its own. Further evaluation, including clinical symptoms and other tests, is needed for diagnosis.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

ANCA-P3 Antibody

Frequently asked questions

What Does a Positive Result Mean?
A positive test result for anti-Proteinase 3 antibodies strongly suggests **c-ANCA vasculitis**, a type of vasculitis that affects small blood vessels. This condition requires prompt medical attention to prevent organ damage. Your doctor will likely order additional tests and follow-up to guide treatment, which may include medications to control inflammation.
What If My Results Are Negative?
A negative result means no detectable antibodies against Proteinase 3, which reduces the likelihood of c-ANCA vasculitis. However, other types of vasculitis or autoimmune conditions may still be possible. Your doctor may recommend further testing or monitoring based on your symptoms and medical history.
How Often Should I Get This Test?
The frequency of testing depends on your medical condition. If you have vasculitis, your doctor may order this test periodically to check for disease progression or response to treatment. Follow their guidance closely.
  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