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What to Know About High Monocyte Count

Reviewed by Dan Brennan, MD on April 14, 2021

Your blood is made up of red blood cells, white blood cells, platelets, and plasma. White blood cells only make up about 1% of your blood, but they have an important function. As part of your immune system, they protect you against illnesses. There are five different types of white blood cells, and each one has a specific purpose. 

What Are Monocytes?

Monocytes are a type of white blood cell. They are produced in the bone marrow and then enter the bloodstream. They fight certain infections and help other white blood cells remove dead or damaged cells and fight cancer cells. After a few hours, monocytes move from the blood to tissues — such as lung, liver, or spleen tissue — and are then called macrophages. 

Monocytes are one of the five different types of white blood cells. The others include:

  • Lymphocytes create antibodies to fight against viruses and bacteria.
  • Basophils secrete chemicals such as histamine to help your body's immune response.
  • Neutrophils are your body's first line of defense. They are the most numerous type of white blood cells. They kill bacteria and fungi. 
  • Eosinophils help with your body's allergic response and kill cancer cells and parasites. 

What Does a High Monocyte Count Mean?

A high monocyte count — also called monocytosis — is often associated with chronic or sub-acute infections. It can also be linked with some types of cancer, especially leukemia. A high monocyte count can occur when you are recovering from an acute infection. 

Some conditions that can cause monocytosis include: 

How Is a High Monocyte Count Measured?

Monocytes are measured with a blood test called a white blood count (WBC) differential.  It's often part of a complete blood count (CBC). A CBC does tests on the red blood cells, white blood cells, and platelets in your blood. A CBC is a routine part of an annual physical exam. If the result shows a high or low white blood count, your doctor may order a WBC differential test.

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A CBC with WBC differential tells your healthcare provider how many of each of the five types of white blood cells you have. It tells if the number of white blood cells you have is in normal in proportion to each other, if there are more or less of them than normal, and if any abnormal or immature white blood cells are present. 

A WBC differential is done by collecting a sample of your blood from a vein or by pricking your finger. No special preparation is needed for this test.  

What Is a Normal Monocyte Count?

Monocytes normally make up between 2% and 8% of your total white blood cells. The complete range of normal white blood cells includes:

  • Neutrophils: 2500 to 8000 per mm3, between 55% and 70% of total white blood cells
  • ‌Lymphocytes: 1000 to 4000 per mm3, between 20% and 40% of total white blood cells
  • Monocytes: 100 to 700 per mm3, between 2% and 8% of total white blood cells
  • Eosinophils: 50 to 500 per mm3, between 1% and 4% of total white blood cells
  • Basophils: 25 to 100 per mm3, between 0.5% and 1% of total white blood cells 

How Is a High Monocyte Count Treated?

The treatment for monocytosis will depend on the cause. Monocytosis itself is only a symptom and doesn't require treatment. Treating the underlying cause will resolve the monocytosis. A high monocyte count can have a wide range of causes. Your doctor may do additional tests to help determine the cause of your monocytosis. Once the cause is determined, you will be given an appropriate treatment plan if needed.

What Can You Do About a High Monocyte Count?

While some causes of monocytosis will only respond to medical treatment, there are some causes that you can improve with lifestyle changes. There is evidence that you can improve your monocyte function with exercise, especially as you age. Both aerobic and strength-training exercises can benefit your monocyte function, which will help you fight illness and disease.

Additionally, since monocytes are associated with inflammation, eating an anti-inflammatory diet may help. Foods that are high in antioxidants and polyphenols, which are the protective compounds found in plants, can help fight inflammation. Examples of these foods include:

  • Green, leafy vegetables such as kale, spinach, and collards
  • Nuts, including walnuts and almonds
  • Fruits such as strawberries, blueberries, oranges, and cherries
  • Fatty fish, including salmon, mackerel, and sardines
  • Olive oil
  • Tomatoes

You should also avoid foods that cause inflammation like: 

  • Red meat such as burgers and steaks 
  • Processed meat such as hot dogs
  • Refined carbohydrates like white bread and pastries
  • Fried foods
  • Soda and other beverages high in sugar
  • Margarine, shortening, and lard
WebMD Medical Reference

Sources

SOURCES: 

Brain Behavior and Immunity: "The Dietary Inflammatory Index is Associated with Elevated White Blood Cell Counts in the National Health and Nutrition Examination Survey."

Cancer Therapy Advisor: "Monocytosis."

Exercise Medicine: "Monocytes in Aging and Exercise."

Harvard Health Publishing: "Foods that fight inflammation."

Lab Tests Online: "White Blood Cell (WBC) Differential."

Medscape: "Differential Blood Count."

Merck Manual: "Monocyte Disorders."

Primary Care Notebook: "monocytosis."

University of Rochester Medical Center: "What Are White Blood Cells?"

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