Skip to content

Proteinase 3 Anti-Neutrophil Cytoplasmic Antibody (PR3-ANCA)

Published: July 27, 2026Updated: August 25, 2026

PR3-ANCA is an antibody directed against proteinase 3, a protein found in neutrophil granules, and is primarily associated with granulomatosis with polyangiitis (GPA), formerly known as Wegener's granulomatosis.

Quick summary

PR3-ANCA is a diagnostic biomarker for GPA, an autoimmune vasculitis.

Medically reviewed by WellAlly Editorial TeamLast reviewed August 25, 2026Editorial policy

Key facts at a glance

Units
U/mL
Clinical utility
diagnostic
Result kind
quantitative
FDA-cleared
Roche PR3-ANCA, Abbott PR3-ANCA, Euroimmun PR3-ANCA
interpretation: {"text":"0–20 U/mL: Levels within this range are generally considered normal and indicate a lower likelihood of GPA.","label":"Normal"}; {"text":">20 U/mL: Levels above 20 U/mL may suggest the presence of GPA or another autoimmune condition.","label":"Elevated"}

PR3-ANCA is measured in units per milliliter (U/mL) and is typically used to aid in the diagnosis of systemic vasculitides, particularly granulomatosis with polyangiitis (GPA).

Elevated levels of PR3-ANCA in the blood can indicate the presence of an autoimmune condition, with levels above 20 U/mL often considered clinically significant.

This biomarker is also useful in monitoring disease activity and treatment response in patients diagnosed with GPA.

Frequently asked questions

What conditions are associated with a positive PR3-ANCA test?
A positive PR3-ANCA test is most commonly associated with granulomatosis with polyangiitis (GPA), but it can also be found in other autoimmune conditions.
How is PR3-ANCA testing used in disease management?
PR3-ANCA testing is used to diagnose GPA, monitor disease activity, and assess the effectiveness of treatment.
  1. 1
    National Institute of Allergy and Infectious DiseasesSource
  2. 2
    Mayo ClinicSource

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 25, 2026. · Read our editorial policy