Monocytes are a type of white blood cell. They help fight bacteria, viruses, and other infections in your body. A high monocyte level may be a sign of inflammation, infection, acute stress, blood disorders, and other health issues.
Along with other types of white blood cells, monocytes are a key element of your immune response. High levels can result from a range of issues, including leukemia, radiotherapy, spleen removal, and tuberculosis (TB).
However, it is worth noting that doctors need to interpret monocyte levels in the context of other factors and tests. Just having a high monocyte level is not enough to diagnose any health issue.
Let’s take a closer look at monocytes, their role in keeping you healthy, and what it means when your monocyte levels are high.
In addition to platelets and plasma, your blood contains red and white blood cells. Only about 1 percent of your blood is comprised of white blood cells, but they play a huge role in protecting you from illness. There are five types of white blood cells, each with a specific purpose.
Your bone marrow produces monocytes and releases them into your bloodstream. Once they reach tissues in your body, they’re called macrophages.
There, they isolate and clean up germs and other harmful microorganisms. They also get rid of dead cells and assist in the immune response.
Here’s a bit about the other types of white blood cells:
- Basophils secrete chemicals to help mediate the body’s response to allergies and infectious agents.
- Eosinophils respond to parasites and cancer cells and assist with allergic response.
- Lymphocytes produce antibodies against bacteria, viruses, and other invaders.
- Neutrophils kill bacteria and fungi.
Some types of white blood cells typically only live for 1 to 3 days, so your bone marrow is constantly producing more.
White blood cells live in a delicate balance. When one type is high, another might be low.
Looking at monocytes alone may not give you the whole picture. That’s why each type of white blood cell will be listed as a percentage on your blood test report. This report may refer to the overall count as the leukocyte count. It’s another term for white blood cell count.
Monocytes typically make up a fairly small percentage of your white blood cells. They can be referred to as absolute monocytes or “monocytes (absolute)” in blood test results when a count of monocytes is reported.
The typical percentage range of each type of white blood cell is:
- Monocytes: 2 to 8 percent (100 to 700 per mm3, or cells per cubic millimeter)
- Basophils: 0.5 to 1 percent
- Eosinophils: 1 to 4 percent
- Lymphocytes: 20 to 40 percent
- Neutrophils: 55 to 70 percent
- Young neutrophils (band): 0 to 3 percent
An absolute monocyte count above
If your monocyte count is high, you may not have symptoms. Any symptoms you have may be associated with the underlying cause.
In general, symptoms may include:
Your monocyte level and overall white blood count are likely to rise in response to:
- acute stress
- blood disorders
- immune response
In many cases, the balance between different types of white blood cells helps tell the tale.
The following are some of the conditions that may be risk factors for elevated monocyte levels:
- viral infections, such as infectious mononucleosis, mumps, and measles
- parasitic infections
- bacterial infections, including TB
- chronic inflammatory disease
autoimmune diseases, such as rheumatoid arthritis, inflammatory bowel disease (IBD), and celiac disease medicationsand other treatments, such as the antipsychotic drug ziprasidone (Geodon), granulocyte colony stimulating factor (G-CSF) drugs that increase white blood cells, and radiation therapy
- spleen removal
To know how many monocytes are circulating in your blood, you’ll need a blood differential test. This test determines the level of each type of white blood cell in your blood. It can also tell if some types of white blood cells are atypical or immature.
The blood differential test is done the same way as most other blood tests. A medical professional will draw a sample of blood from a vein in your arm. You do not have to fast or do anything in preparation for this test.
Once your blood is drawn, a special dye helps the pathologist count the different types of white blood cells in your blood sample.
It’s a test your doctor might order with a complete blood count to help diagnose infection or conditions, like anemia and leukemia.
Treatment of elevated monocytes depends on the cause. Your doctor may have to do more tests to determine the underlying cause.
Generally, treatment may include the following:
- Treatment for viral infections usually focuses on symptom management.
- Antibiotics can treat many bacterial infections, such as TB.
- There are many types of parasitic diseases. You’ll likely need other lab tests to determine the exact cause before the correct medication can be prescribed.
Treatment for blood cancers can include:
When it comes to white blood cells, you want to keep them all within the healthy range. If your white blood cell count is too low, you’ll be more vulnerable to illness. If it’s too high, it may mean your body is responding to something.
Regular exercise is an important component to overall good health and maintaining the right blood counts. There’s some evidence to suggest exercise can help improve monocyte function, especially as you age.
Since monocytes respond to inflammation, an anti-inflammatory diet might be beneficial. Anti-inflammatory foods include:
- olive oil
- green leafy vegetables
- strawberries, blueberries, cherries, and oranges
- fatty fish, such as salmon, tuna, sardines, and mackerel
Some foods, like those listed below, can increase inflammation. Try to limit:
- red and processed meat
- refined carbohydrates, like baked goods, white bread, and white pasta
- fried foods
- soda and other sugary drinks
- margarine, shortening, and lard
The Mediterranean diet is a good example of an anti-inflammatory diet. It includes a lot of fresh vegetables, fruit, nuts, seeds, fish, olive oil, and whole grains.
The white blood cell count is complicated. If you think your monocyte level is too high, talk with your doctor about why that is, whether you need treatment, and if lifestyle changes may be helpful.
Monocytes, along with other types of white blood cells, are a vital part of your immune system. They help protect you against infection and illness.
If your monocytes are higher than they should be, a doctor can work with you to find the cause and start any treatments that may be necessary.