🔬 What is this Test?
The ANCA-C Test detects Cytoplasmic Anti-Neutrophilic Cytoplasmic Antibodies (C-ANCA) in the blood. It helps diagnose autoimmune vasculitis, especially Granulomatosis with Polyangiitis (GPA, formerly Wegener’s granulomatosis).
📊 Normal Ranges:
✅ Negative: No detectable C-ANCA (<1:20 dilution)
⚠️ Low Positive: Borderline, may need further testing (1:40 to 1:80 dilution)
❌ High Positive: Suggestive of active autoimmune disease (>1:160 dilution)
🎯 Purpose of the Test:
✔️ Diagnose autoimmune vasculitis disorders
✔️ Identify C-ANCA pattern, associated with PR3 antibodies
✔️ Monitor disease activity and treatment response
✔️ Differentiate between types of vasculitis (GPA vs. MPA, EGPA)
🩺 C-ANCA vs. P-ANCA:
🔹 C-ANCA (Cytoplasmic ANCA - PR3 Antibody) → Strongly associated with Granulomatosis with Polyangiitis (GPA)
🔹 P-ANCA (Perinuclear ANCA - MPO Antibody) → More common in Microscopic Polyangiitis (MPA) and EGPA
⚠️ Who Might Need This Test?
Persistent sinusitis or lung issues with unknown cause
Kidney dysfunction with blood in urine (hematuria)
Skin ulcers, nodules, or rashes
Neuropathy (nerve pain) or unexplained systemic inflammation
📌 Understanding the Results:
Negative C-ANCA: No significant autoimmune vasculitis detected
Low-Positive C-ANCA: May require additional testing
High-Positive C-ANCA: Suggests active disease, requiring medical attention
🔬 Additional Notes:
A positive C-ANCA test is often accompanied by PR3-ANCA testing
Higher titres may indicate more severe disease
Results should be interpreted with clinical symptoms and other lab tests