PR3 (c-ANCA)

PR3 antibodies are formed when the immune system mistakenly attacks the PR3 enzyme, found inside neutrophils. These antibodies are also called c-ANCA (cytoplasmic antineutrophil cytoplasmic antibodies) due to their staining pattern (diffuse, granular appearance of cytoplasm) during lab tests.

The PR3 (c-ANCA) test helps diagnose autoimmune diseases such as GPA and other forms of vasculitis, monitor disease activity, guide treatment decisions, and rule out other conditions that can cause similar symptoms, such as infections or other autoimmune diseases.

A doctor may advise a PR3 (c-ANCA) test when there are symptoms of autoimmune vasculitis. General symptoms may include fever, fatigue, headache, weight loss, aches and pains, etc. Other symptoms depend on the parts of the body affected.

No special preparation is required for the PR3 (c-ANCA) test. Inform a doctor about all the medications (e.g., immunosuppressants, steroids, etc.) and supplements (e.g., biotin, etc.) that are currently being taken, as some of them may affect the test results, potentially requiring dosage adjustments or temporary discontinuation before the test.

Test result ranges are approximate and may differ slightly between labs depending on the methodology and laboratory guidelines. Do not self-medicate, and always consult a doctor to understand the test results correctly.