Myeloperoxidase (MPO) Activity in Serum
This test measures the activity of myeloperoxidase, an enzyme produced by white blood cells (neutrophils) that plays a role in immune responses and inflammation.
["MPO helps assess immune function and inflammation in your blood."]
Key facts at a glance
- LOINC
- 111021-2
- Short code
- Myeloperoxidase Ab Msmt Ser
- Synonyms
- Myeloperoxidase Ab Msmt Ser
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What Does This Test Measure?
Myeloperoxidase (MPO) is an enzyme found in the granules of neutrophils, a type of white blood cell. This test evaluates its functional activity in your serum. MPO is involved in producing reactive oxygen species that help fight infections and contribute to inflammation. Measuring MPO activity can help doctors understand how effectively your immune system is responding to certain conditions.
Why Might This Test Be Ordered?
Your healthcare provider may order this test if they suspect an inflammatory condition, such as certain autoimmune diseases, infections, or to evaluate immune function in patients with suspected neutropenia (low neutrophil count). It may also be used in research or specialized clinical settings to monitor immune responses.
Sample Collection and Preparation
A blood sample is drawn from a vein, usually in your arm. The blood is then processed to separate the serum, which is sent to the lab for testing. This test does not require fasting and is typically performed on fresh serum samples.
What to Expect Before the Test
There are no special preparations needed for this test. You may eat and drink as usual before your blood draw. If you are on blood-thinning medications, let your healthcare provider know before the test.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated MPO activity may indicate increased inflammation or immune activation, potentially linked to conditions such as infections, autoimmune diseases, or certain cancers. Lower than expected levels could suggest impaired neutrophil function or a deficiency in immune cell activity. This test is often used in conjunction with other diagnostic tests for a comprehensive evaluation.
Short name
Serum MPO Activity
Frequently asked questions
How Long Does It Take to Get Results?
What Are Common Causes of Abnormal Results?
Is This Test Painful?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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 16, 2026. · Read our editorial policy