Your blood contains several different types of cells, including red blood cells, white blood cells, and platelets. Doctors order blood tests because they want to examine these cells for signs of health problems.
One of the most common tests that doctors run is a complete blood count (CBC). CBC is an umbrella term for a series of tests that look at specific types of cells in your blood.
One of the tests run during a CBC is a mean platelet volume (MPV) test. An MPV test measures the average size of your platelets. It's closely related to a platelet count test, which measures the number of platelets in your blood.
Platelets are small blood cells that play an essential role in blood clotting. When you cut yourself, for example, platelets stick together to stop the bleeding. In some cases, platelet abnormalities can be a sign of a bleeding disorder or other health problem.
Having a high or low MPV doesn't mean anything on its own. It should be interpreted within the context of other CBC results, such as platelet count. In most cases, your doctor will simply use your MPV test results to decide whether or not to do additional testing, such as a bone marrow biopsy.
Also keep in mind that several things can affect your MPV, including living at a high altitude or following a vigorous exercise routine. Make sure you go over your test results with your doctor so you get the full picture.
Testing your MPV is an easy process. It's typically done as part of your annual checkup with your primary care physician.
A phlebotomist (a person specially trained in drawing blood) will wrap a tourniquet around your arm to make your veins engorge. Then they'll insert a thin needle into your vein and draw your blood into test tubes. The pain should be minimal, but you may have some bruising and tenderness for a few days.
A high MPV means that your platelets are larger than average. This is sometimes a sign that you're producing too many platelets.
Platelets are produced in the bone marrow and released into the bloodstream. Larger platelets are usually young and more recently released from the bone marrow. Smaller platelets are more likely to have been in circulation for a few days.
When someone has a low platelet count and a high MPV level, it suggests that the bone marrow is rapidly producing platelets. This may be because older platelets are being destroyed, so the bone marrow is trying to compensate.
Increased MPV is associated with platelet activation, which can happen when platelets encounter tumor byproducts. Still, a high MPV doesn't mean you have cancer. However, if you have a family history of cancer or other risk factors, your doctor might do some additional testing to make sure there are no other signs.
If you do have cancer, a high MPV may be a warning sign, depending on the results of other blood tests. Platelets can help cancer spread to other parts of the body and promote tumor growth.
A high MPV suggests increased platelet production, which is associated with reduced survival rates in several types of cancer, including:
- lung cancer
- ovarian cancer
- endometrial cancer
- colon cancer
- kidney cancer
- stomach cancer
- pancreatic cancer
- breast cancer
Keep in mind that MPV only refers to the size of your platelets, not the actual number of them. Your MPV alone doesn't mean you have anything.
If you're worried about cancer, familiarize yourself with these early warning signs from the National Cancer Institute:
- skin changes
- breast changes
- thickening skin or lump on or under your skin
- hoarseness or cough that doesn't go away
- changes in bowel habits
- difficult or painful urination
- appetite changes
- trouble swallowing
- weight gain or loss for no reason
- abdominal pain
- unexplained night sweats
- unusual bleeding or discharge in urine or stool
- feeling weak or very tired
Depending on your other CBC results, high MPV levels can be an indicator of several conditions, such as:
- heart disease
- vitamin D deficiency
- high blood pressure
- atrial fibrillation
A low MPV means your platelets are smaller than average. Smaller platelets tend to be older, so a low MPV could mean your bone marrow isn't producing enough new ones. Again, a low MPV on its own doesn't mean anything.
Depending on your other CBC results, a low MPV could indicate:
- inflammatory bowel disease, including Crohn's disease or ulcerative colitis
- cytotoxic medications, which are used in chemotherapy
- aplastic anemia
An MPV test measures the average size of your platelets. While closely related, it's different from your platelet count, and you can have a combination of a high MPV and a low platelet count, or a low MPV and a high platelet count.
Depending on your lifestyle, a high or low MPV may be completely normal for you. However, based on other results from your CBC, it can signal to your doctor to do additional testing to rule out any possible underlying conditions.
On its own, though, a high or low MPV doesn't mean anything about your risk of having cancer or a certain type of disease.