Clinical definition of the MPO (p ANCA) test
Myeloperoxidase (MPO) is a peroxidase enzyme most abundantly present in neutrophil granulocytes (a subtype of white blood cells). Myeloperoxidase deficiency is a hereditary deficiency of the enzyme which predisposes into immune deficiency. MPO level in the blood serves as a risk factor for artherosclerosis, coronary artery disease, myocardial infarction and other adverse cardiac events including severe chest pain. Antibodies against MPO are seen in various types of Vasculitis such as Crescentic Glomerulonephritis and Churg- Strauss Syndrome. They are detected as Perinuclear ANCAS (pANCAs).

Why is the MPO (p ANCA) test done?
MPO is carried out to test for autoimmune disorders such as Wegner’s Granulomatosis (WG), microscopic Polyangitis (MPA).

What are the common signs/symptoms when the MPO (p ANCA) test is done?
Early symptoms include:

  • Fever
  • Fatigue
  • Weight loss
  • Muscle and or/joint aches
  • Night sweats

As the disease progresses, damage to blood vessels throughout the body cause the following signs and symptoms:

  • Eyes — red, itchy eyes or "pink eye" (conjunctivitis); problems with sight (blurry vision, loss of vision)
  • Ears — hearing loss
  • Nose — runny nose or other persistent upper respiratory symptoms that do not go away
  • Skin — rashes and/or granulomas
  • Lungs — cough and/or difficulty breathing
  • Kidneys — abnormal amounts of protein in the urine

What should I do before the MPO (p ANCA) test?

Specimen type

Specimen collection procedure

Preparatory instructions before the test *

Serum (Blood Sample)


Collection of blood from a vein, usually from the arm.

No Fasting Required.

No other special preparations required.

* Subjects suffering from any illness or on oral or injectable medications are advised to consult their physician prior to requesting any tests or procedures.

How do I interpret my MPO test results?

Reference Range*


Below 20 RU/ml


20 and above RU/ml


 ‘*A Reference range is a set of values which helps the healthcare professional to interpret a medical test. It may vary with age, gender, and other factors. Reference ranges may also vary between labs, in value & units depending on instruments used and method of establishment of reference ranges’

Diseases/conditions related to the MPO (p ANCA) test

  • Myocardial Infarction
  • Acute Myeloid Leukemia
  • Lung Cancer
  • Alzheimer’s Disease
  • Multiple Sclerosis
  • Cardiovascular Diseases
  • Aneurysms
  • Rheumatoid Arthritis

Other tests related to the MPO (p ANCA) test

  • ESR (erythrocyte sedimentation rate)
  • CBC (complete blood count)
  • BUN (blood urea nitrogen)
  • Creatinine
  • Urinalysis
  • Autoantibodies

Synonyms : Myeloperoxidase Antibodies, P- Antineutrophil Cytoplasmic Antibodies