Quick Facts
- Sample: Blood (serum)
- Fasting: Not required
- Turn-around: 5-7 business days. May take longer based on weather, holiday, or lab delays.
Benefits
- Detect autoimmune vasculitis early — identify MPO antibodies linked to microscopic polyangiitis and EGPA.
- Monitor disease activity conveniently — track treatment response and predict relapse risk without specialist visits.
- No fasting needed — quick blood draw with results in days.
- Distinguish vasculitis subtypes — pairs with PR3 testing for comprehensive ANCA-associated vasculitis assessment.
Who Is This Test For?
- Patients with unexplained kidney or lung inflammation
- Individuals experiencing systemic vasculitis symptoms like joint pain or rashes
- Those monitoring known ANCA-associated vasculitis or treatment effectiveness
- People with recurring inflammation needing diagnostic clarity
- Patients tracking remission status to catch early relapse signs
How It Works – Just 3 Steps
- Order online — Select your test and complete a brief health questionnaire.
- Visit a lab near you — Get a simple blood draw at any of our nationwide partner locations.
- Receive confidential results — Access your results online within 5-7 business days.
FAQ
What does this test measure? It detects IgG antibodies against myeloperoxidase, an enzyme in neutrophils associated with autoimmune vasculitis (Mayo Clinic 2024).
Is fasting required before the test? No, you can eat and drink normally before your blood draw.
How accurate is the MPO antibody test? It shows approximately 82% sensitivity and 90% specificity for microscopic polyangiitis when combined with PR3 testing (ACR 2024).
Can this test predict disease flare-ups? Yes, rising MPO-ANCA levels during remission predict relapse with over 79% accuracy (Frontiers in Immunology 2025).
Will I need a doctor's prescription? No prescription needed — order directly and consult your provider with results.
What if my results are positive? Positive results warrant rheumatologist consultation to confirm diagnosis and guide treatment decisions.
More Details
What is the purpose of this test?
The Myeloperoxidase Antibody (MPO) Blood Test identifies antibodies targeting myeloperoxidase, an enzyme found in white blood cells called neutrophils. These MPO antibodies are strongly associated with ANCA-associated vasculitis, particularly microscopic polyangiitis (MPA) and eosinophilic granulomatosis with polyangiitis (EGPA). The test uses high-sensitivity immunoassays to measure serum MPO antibody levels, helping diagnose autoimmune vasculitis and monitor disease activity or treatment response (Mayo Clinic 2024).
About 90% of patients showing a perinuclear ANCA pattern have MPO-specific antibodies, making this test highly relevant for diagnostic workups (Mayo Clinic 2024).
Who would benefit from this test?
This test is valuable for patients experiencing symptoms of systemic vasculitis affecting small blood vessels. You may benefit if you have unexplained kidney dysfunction, lung involvement, recurring inflammation, or symptoms like joint pain, rashes, fever, or fatigue. It's also essential for individuals with known ANCA-associated vasculitis who need to monitor disease progression or evaluate how well treatment is working.
When should I order a Myeloperoxidase Antibody (MPO) Blood Test?
Order this test when clinical suspicion exists for ANCA-associated vasculitis, particularly microscopic polyangiitis or eosinophilic granulomatosis with polyangiitis. Symptoms warranting testing include persistent inflammation, unexplained kidney or respiratory problems, joint and muscle pain, abnormal heart rate, shortness of breath, skin rashes or ulcers, and unexplained weight loss. Serial testing helps track treatment effectiveness and identify early signs of disease relapse during remission.
How do I interpret the results?
MPO antibody levels are reported in quantitative units (AU/mL). Results require clinical correlation with your symptoms and medical history for accurate interpretation.
MPO Antibody ≤26 AU/mL
- Meaning: Negative — no significant MPO antibodies detected
- Typical action: Monitor symptoms; consider alternative diagnoses or retest if clinical suspicion persists
MPO Antibody >26 AU/mL
- Meaning: Positive — MPO antibodies present, suggesting ANCA-associated vasculitis
- Typical action: Consult rheumatologist for further evaluation, confirmatory testing, and treatment planning
Rising MPO antibody levels during remission
- Meaning: Increased relapse risk
- Typical action: Adjust treatment regimen; increase monitoring frequency to help prevent disease flare
Some individuals may have low-level antibodies without active disease, so interpretation must consider your full clinical picture.
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
Pre-test preparation
No fasting is required for this test. You can eat, drink, and take medications normally before your blood draw. However, inform your healthcare provider about all medications you're taking and provide relevant clinical context, as certain immunosuppressive therapies may affect antibody levels. The test requires a standard venous blood sample collected in a serum separator tube.
How often should I get tested?
Testing frequency depends on your clinical situation and disease status.
- Initial diagnosis / new symptoms: One-time baseline test with PR3 antibody testing
- Active vasculitis under treatment: Every 3–6 months to monitor treatment response
- Disease remission: Every 6–12 months to detect early relapse signs
- Rising symptoms or suspected flare: Immediate testing to guide treatment adjustments
Why early detection matters
Early detection of MPO antibodies enables timely diagnosis of ANCA-associated vasculitis before serious organ damage occurs. Untreated vasculitis can cause permanent kidney failure, lung hemorrhage, and other life-threatening complications. Monitoring MPO levels during treatment helps predict relapse with positive predictive value exceeding 79%, allowing your medical team to adjust therapy proactively and prevent disease flares (Frontiers in Immunology 2025). This proactive approach reduces hospitalizations, preserves organ function, and improves long-term outcomes.
Related tests you may consider
Proteinase 3 (PR3) Antibody Test - Detects antibodies to proteinase 3 to help screen for Wegener's granulomatosis.
Antineutrophil Cytoplasmic Antibodies (ANCA) Blood Test - Detects and measures ANCA in the blood to screen for certain forms of systemic vasculitis.
Complete Blood Count (CBC) and Comprehensive Metabolic Panel (CMP-14) Blood Test Panel - Used to diagnose and monitor health conditions by evaluating blood cells, liver and kidney function, and detecting diabetes.
