What Are Monocytes in a Blood Test?

Monocytes are white blood cells that circulate in the blood and become macrophages in tissues, engulfing debris and pathogens.

Normal Range

• 2–8% of WBC
• Absolute: 200–800/µL

High Monocytes (Monocytosis)

• Chronic infection (tuberculosis, endocarditis)
• Recovery phase after acute infection
• Autoimmune disease
• Inflammatory bowel disease
• Leukemia (rare)

Low Monocytes

• Usually not clinically significant
• Bone marrow suppression
• Corticosteroid use