Monocytes are a type of white blood cell produced by the bone marrow then released into the blood. They ingest bacteria and other foreign particles. Monocytes account for 2-8% of the total white blood cell count. Monocytes function to fight infections and help other white blood cells remove dead or damaged tissues, and regulate the immune response against foreign substances.
Monocytes are measured as part of a full blood count and can be used to evaluate the function of the immune system and the bone marrow.
An increased number of monocytes in the blood is called monocytosis and can occur in response to long term infections, autoimmune disorders, in blood disorders, and can increase in certain cancers such as leukaemia
A low number of monocytes in the blood is called monocytopenia can be caused by anything that decreases the overall white blood cell count such as infection, autoimmune disorders, chemotherapy, or a bone marrow disorder.