From the Research
A high monocyte count is typically caused by chronic infections, inflammatory conditions, certain cancers, or autoimmune disorders, as evidenced by recent studies 1, 2. The most common specific causes of a high monocyte count include:
- Bacterial infections like tuberculosis and endocarditis
- Viral infections such as mononucleosis and cytomegalovirus
- Fungal infections
- Inflammatory bowel disease
- Rheumatoid arthritis
- Lupus
- Leukemias, particularly chronic myelomonocytic leukemia and monocytic leukemia
- Lymphomas
- Recovery from bone marrow suppression Certain medications can also elevate monocyte counts, including corticosteroids, carbamazepine, and colony-stimulating factors, as noted in various studies 3, 4.
Monocytosis occurs because these conditions trigger the immune system to produce more monocytes, which are white blood cells that fight infections, remove damaged tissues, and regulate immune responses 1. Normal monocyte levels range from 2-8% of white blood cells or 200-800 cells per microliter of blood. If you have an elevated monocyte count, further testing is usually needed to determine the underlying cause, as treatment should target the specific condition rather than the monocytosis itself, according to the most recent and highest quality study 2.
Some key points to consider when evaluating a high monocyte count include:
- The role of monocytes in inflammation and immune responses 2
- The potential for monocytes to contribute to disease progression or regression 4
- The importance of identifying the underlying cause of monocytosis to guide treatment 1
- The need for further testing to determine the underlying cause of an elevated monocyte count 2