Monocytes (monos), although small in number, perform an important defense function in the body. These large cells are phagocytes and respond to bacteria in the same manner as neutrophils. Monocytes remain in circulation longer than neutrophils and phagocytize bacterial and cellular debris. Phagocytosis is the process of engulfing and destroying microorganisms and cellular debris. Monocytes also act as phagocytes in some chronic inflammatory diseases such as arthritis.
Normal Range Monocytes 2-8% of all white cells.
An increase in the number of monocytes is called monocytosis and is seen during infections such as tuberculosis and bacterial endocarditis. Diseases such as chronic ulcerative colitis, malaria, rheumatoid arthritis, and hemolytic anemia can exhibit an increase in the monocyte count. A decreased monocyte count is not usually identified with any specific disease processes.