Cardio IQ Myeloperoxidase (MPO) Biomarker Testing
It measures MPO, an inflammation-related enzyme linked to plaque activity and heart risk, with convenient ordering and Quest lab access via Vitals Vault.
With Vitals Vault, you have access to a comprehensive range of biomarker tests.
Myeloperoxidase (MPO) is an enzyme released by certain white blood cells when they are activated during inflammation. In the cardiovascular setting, MPO is used as a blood marker that can reflect inflammatory activity in blood vessels and within atherosclerotic plaque.
An MPO result does not tell you whether you have a blockage, and it cannot diagnose a heart attack. What it can do is add context to your overall risk picture, especially when you are trying to understand whether “inflammation” may be playing a role alongside cholesterol, blood pressure, blood sugar, and family history.
Because MPO is not the same thing as cholesterol, it is often most useful when you interpret it next to other cardiometabolic labs rather than in isolation.
Do I need a Cardio IQ Myeloperoxidase (MPO) test?
You might consider an MPO test if you are trying to refine your cardiovascular risk beyond a standard lipid panel. This is especially relevant if you have a strong family history of early heart disease, you have metabolic risk factors (such as insulin resistance or high blood pressure), or your usual cholesterol numbers do not seem to match your personal risk story.
MPO testing can also be helpful when you are already working on risk reduction and want another data point to track over time. For example, if you have made changes to diet, exercise, weight, smoking status, or medications, trending MPO alongside other markers may help you and your clinician judge whether vascular inflammation is moving in the right direction.
You do not usually need MPO testing for routine screening if your risk is clearly low and your standard labs are consistently reassuring. And if you have chest pain, shortness of breath, or other urgent symptoms, you should seek immediate medical care rather than relying on an outpatient biomarker.
This test is meant to support clinician-directed care and shared decision-making, not self-diagnosis.
MPO is measured from a blood sample in a CLIA-certified laboratory; results should be interpreted in clinical context and are not a standalone diagnosis of cardiovascular disease.
Lab testing
Order Cardio IQ Myeloperoxidase (MPO) testing
Schedule online, results typically within about a week
Clear reporting and optional clinician context
HSA/FSA eligible where applicable
Get this test with Vitals Vault
Vitals Vault lets you order Cardio IQ Myeloperoxidase (MPO) testing directly, so you can get an objective data point without waiting for a separate office visit just to place the order. After you check out, you complete your blood draw at a participating lab location.
Once your result is back, you can use PocketMD to ask practical questions like what a “high” MPO might mean for you, what other labs commonly clarify the picture (such as hs-CRP, ApoB, or Lp(a)), and when it makes sense to repeat testing. If you are already working with a clinician, you can bring your report to that visit and use it to guide next steps.
If your goal is broader mapping, you can also pair MPO with companion cardiometabolic tests through Vitals Vault so you are not making decisions from a single number.
- Order online and complete your draw at a participating lab location
- PocketMD helps you interpret results and plan follow-up questions
- Designed for trending over time, not one-off guesswork
Key benefits of Myeloperoxidase (MPO) testing
- Adds an inflammation-focused signal that complements cholesterol and lipoprotein testing.
- Can help identify higher-risk patterns when standard lipid numbers look “fine” but your history suggests otherwise.
- Supports more personalized conversations about prevention intensity (lifestyle and, when appropriate, medications).
- Useful for trending over time to see whether vascular inflammation appears to be improving.
- Helps differentiate “inflammation-driven risk” from primarily lipid-driven risk when interpreted with other markers.
- May provide additional context in people with metabolic syndrome features or smoking history, where oxidative stress can be higher.
- Pairs well with other cardiometabolic labs so you can interpret your risk picture with fewer blind spots.
What is Myeloperoxidase (MPO)?
Myeloperoxidase (MPO) is an enzyme stored in certain white blood cells (especially neutrophils and monocytes). When these cells are activated as part of inflammation, they can release MPO, which participates in chemical reactions that generate reactive oxidant compounds.
In blood vessels, those oxidant reactions are one reason MPO is discussed in cardiovascular prevention. MPO-related oxidative stress can contribute to endothelial dysfunction (how well the vessel lining works) and may be associated with inflammatory activity inside atherosclerotic plaque. That is why MPO is often described as a marker linked to “plaque activity” rather than simply the amount of cholesterol in the blood.
MPO is not specific to the heart. Because it reflects immune activation, it can rise with infections and other inflammatory conditions. The most useful interpretation comes from looking at your MPO result alongside your symptoms, your overall risk profile, and other lab markers.
How MPO differs from hs-CRP
High-sensitivity C-reactive protein (hs-CRP) is a liver-produced protein that rises with systemic inflammation. MPO is an enzyme released by activated white blood cells and is often framed as more directly connected to oxidative processes in the vessel wall. In practice, the two tests can be complementary: hs-CRP can reflect broader inflammatory burden, while MPO may add another angle on vascular inflammatory activity.
Where MPO fits in a heart-risk workup
MPO is typically used as an add-on marker, not a first-line screening test. It is most informative when you also know your ApoB or LDL particle burden, triglycerides, blood pressure, glucose/insulin status, and key inherited risks such as lipoprotein(a).
What do my Myeloperoxidase (MPO) results mean?
Low MPO
A low MPO result generally suggests less measurable MPO-related inflammatory activity at the time of the blood draw. For many people, that is reassuring when it matches a broader picture of low cardiometabolic risk. However, a low result does not “rule out” atherosclerosis, because plaque burden and plaque activity are different concepts. If you have strong risk factors, your clinician may still focus on proven prevention targets like ApoB, blood pressure, and glucose control.
In-range (optimal) MPO
An in-range MPO result suggests that this particular marker is not elevated right now. It is most meaningful when it aligns with other favorable markers, such as low ApoB, healthy triglycerides, and low hs-CRP. If you are monitoring changes, an in-range result can serve as a baseline for future comparison. Ask your clinician which reference range your lab used, since cutoffs can vary by method and reporting format.
High MPO
A high MPO result can indicate increased activation of white blood cells and higher oxidative inflammatory activity at the time of testing. In cardiovascular prevention, that pattern may be discussed as potentially higher vascular inflammation or plaque-related activity, especially if other risk markers are also elevated. It is also common for MPO to rise for non-cardiac reasons, such as a recent infection, inflammatory disease flare, or smoking exposure. A high result is usually a prompt to look for context and consider repeat testing when you are well, rather than a reason to panic.
Factors that can influence MPO
MPO can be affected by acute illness (like a cold or flu), chronic inflammatory conditions, and smoking or recent smoke exposure. Some people see changes with shifts in metabolic health, such as improved insulin sensitivity, weight loss, or better blood pressure control, although MPO is not a direct measure of any one lifestyle factor. Timing matters: testing during or soon after an infection can temporarily elevate results. Because MPO is one piece of the puzzle, it is usually interpreted alongside hs-CRP, a lipid or ApoB-based assessment, and your clinical history.
What’s included
- Myeloperoxidase
Frequently Asked Questions
What is the Cardio IQ Myeloperoxidase (MPO) test used for?
It is used as an additional cardiovascular risk marker that reflects immune activation and oxidative inflammatory activity. It is often ordered to add context beyond standard cholesterol testing, especially when you are refining prevention strategy or trending risk over time.
Do I need to fast for an MPO blood test?
Fasting is not typically required for MPO itself. If you are ordering MPO alongside other cardiometabolic tests (like triglycerides, insulin, or a full lipid panel), your clinician or the lab instructions may recommend fasting so the combined results are easier to interpret.
What is a normal MPO level?
“Normal” depends on the laboratory method and the reference range printed on your report. Use the range provided with your result, and interpret it with your overall risk profile rather than treating a single cutoff as a diagnosis.
Can an infection make MPO high?
Yes. Because MPO is released by activated white blood cells, acute infections or other inflammatory stressors can raise it temporarily. If your result is high and you were recently sick, it is reasonable to discuss repeating the test when you are back to your baseline.
How is MPO different from hs-CRP?
hs-CRP is a liver-produced protein that reflects systemic inflammation, while MPO is an enzyme released by activated white blood cells and is often discussed in relation to oxidative processes in blood vessels. They can move together, but they do not measure the same thing, so ordering both can provide a more complete picture.
How often should MPO be retested?
Retesting depends on why you checked it. If you are trending prevention progress, many clinicians recheck inflammatory and lipid-related markers after a meaningful intervention window (often several weeks to a few months). If the first result may have been affected by illness, retesting once you are well can be more informative.