Monocytes are white blood cells that help fight infections and diseases in your body. A high monocyte level may indicate inflammation, infection, blood disorders, or 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
- tuberculosis (TB)
But it’s worth noting that doctors interpret monocyte levels in the context of other factors and tests. A high monocyte level is not enough to diagnose any health issue.
An absolute monocyte count
The following table shows the
| Type of white blood cell | Typical percentage range |
|---|---|
| monocytes | 2% to 8% (100 to 700 per mm3) |
| basophils | less than 1% |
| eosinophils | 1% to 4% |
| lymphocytes | 20% to 40% |
| neutrophils | 50% to 70% |
Monocytes typically make up a relatively small percentage of your white blood cells. They can be called absolute monocytes or “monocytes (absolute)” in blood test results that report the count.
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. Labs typically list each type of white blood cell 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.
Your monocyte level and overall white blood count may rise in response to:
- acute stress
- blood disorders
- immune response
- infection
- inflammation
In many cases, the balance between different types of white blood cells helps doctors determine the cause.
- viral infections, such as infectious mononucleosis and measles
- parasitic infections
- bacterial infections, including TB
- spleen removal
- chronic inflammatory diseases
autoimmune diseases , such as:medications and other treatments, such as:- the antipsychotic drug ziprasidone (Geodon)
- granulocyte colony-stimulating factor (G-CSF) drugs that increase white blood cells
- radiation therapy
A high monocyte count is also
A 2019 study suggests that a higher monocyte count may also be related to cardiovascular disease risk and that early detection of increased monocytes could help with heart health management. However, more large-scale research is needed to confirm this.
In general, you’ll need to follow your doctor’s treatment plan as closely as possible to keep your monocyte counts in a healthy range.
On your own, regular physical activity can promote overall good health and may help you maintain optimal blood counts. A 2018 research review suggests exercise can help improve monocyte function, especially as you age.
Since monocytes respond to inflammation, an anti-inflammatory diet like the Mediterranean diet may also be beneficial.
Treatment of elevated monocytes depends on the cause. A 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 your doctor can prescribe the appropriate medication.
Treatment for blood cancers like leukemia can include:
- chemotherapy
- radiation therapy
- stem cell transplant
- supportive therapy
- surgery
If your blood test results show a higher monocyte count than usual, your doctor may recommend additional testing to determine the underlying cause. If the cause still isn’t clear, they may refer you to a hematologist (blood specialist).
A hematologist may be able to identify what’s causing a high monocyte count and coordinate further care for you.
Viral infections, such as infectious mononucleosis, mumps, and measles, are the most common cause of a high absolute monocyte count. Other infections that can cause high absolute monocytes include parasitic infections or bacterial infections, including tuberculosis.
Chronic myelomonocytic leukemia (CMML) is a rare type of blood cancer that can cause elevated levels of monoctyes in the blood. Lymphoma and multiple myeloma may also cause high monocyte levels.
People with chronic myelomonocytic leukemia (CMML) typically have monocyte counts of at least 500 per mm3. They may also have lower numbers of other white blood cells, red blood cells, and platelets.
Doctors must order additional tests, including looking at blood cells under a microscope, to diagnose leukemia.
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.