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Myeloperoxidase (MPO) Activity in Blood Cells

Published: August 9, 2026Updated: August 16, 2026

This test measures the activity of myeloperoxidase, an enzyme found in white blood cells (neutrophils). It helps assess immune system function and inflammation.

Quick summary

["MPO activity helps evaluate immune response and potential inflammation in your blood."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
107072-1
Short code
Myeloperoxidase Cells NFr Spec FC
Synonyms
Myeloperoxidase Cells NFr Spec FC
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
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 produced by certain white blood cells called neutrophils. These cells are part of your immune system and play a key role in fighting infections. The test measures how active this enzyme is in your blood cells, which can indicate how well your immune system is functioning or if there is an ongoing inflammatory process.

Why Might Your Doctor Order This Test?

Your doctor may recommend this test if they suspect conditions involving chronic inflammation, immune system disorders, or certain blood disorders. It can also be part of a broader evaluation for autoimmune diseases or infections.

How Is the Sample Collected?

A small amount of blood will be drawn from a vein, usually in your arm, using a needle. After the blood is collected, it will be processed to measure MPO activity.

What Are Common Uses?

This test is often used in conjunction with other blood tests to diagnose or monitor conditions such as chronic granulomatous disease, certain types of leukemia, or inflammatory conditions like vasculitis.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated MPO activity may suggest an overactive immune response or inflammation. Doctors use these results to guide treatment plans, especially for patients with suspected immune-related disorders or chronic infections. However, MPO alone is not typically used for diagnosing specific conditions but rather as part of a comprehensive evaluation.

Short name

MPO Activity

Frequently asked questions

What does an abnormal MPO result mean?
An abnormal result (either too high or too low) may indicate an underlying health issue, such as an immune system disorder or inflammation. Your doctor will consider the result alongside other tests and symptoms to determine the next steps.
How long does it take to get results?
Test results are usually available within a few days to a week, depending on the lab’s processing time and your healthcare provider’s follow-up schedule.
Can lifestyle changes affect MPO test results?
While lifestyle factors like diet and exercise can influence overall health, they typically do not directly affect MPO test results. However, chronic infections or recent illnesses may temporarily alter enzyme activity.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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