High monocyte levels in the blood are referred to as monocytosis, states MedFriendly. Monocytosis may have a common cause such as inflammation, stress or a fever from a virus. It also may be caused by something more complex and potentially more serious.
A monocyte is a type of white blood cell that helps the body fight infection and protects against disease, according to MedFriendly. A monocyte count is ascertained through a blood test called a complete blood count with differential. A CBC provides a breakdown of the kinds and numbers of cells present in the blood. Monocytes react to signals of inflammation and travel to areas of infection or tissue damage as part of the body's immune system response.
Monocytosis is caused by a severe infection such as tuberculosis, listeriosis, subacute bacterial endocarditis, syphilis, brucellosis or malaria, indicates Wikipedia. Inflammatory diseases that cause an elevated monocyte count include rheumatoid arthritis, Crohn's disease, ulcerative colitis or systemic lupus erythematosus, states NTPathology.com. Cancers such as Hodgkin's lymphoma may also result in monocytosis.
Other potential causes for monocytosis include sarcoidosis, Cushing's syndrome or chronic granulomatous disease, states MedFriendly. A health care provider uses the number of monocytes present to help determine a diagnosis.