Monocytes
Immune system healthAlso known as: MONO, Monos
Monocytes develop into macrophages that kill pathogens and dead cells.
Reference range
Source: lab benchmark
Reference ranges may vary between labs and assays. Always interpret results with your healthcare provider.
Why this matters
Monocyte levels provide an early indication of immune system activity before symptoms become severe. Elevated monocytes often signal chronic infections, inflammation, or autoimmune conditions, while very high levels can point to blood cancers. Low monocytes are rare but may impair wound healing. Supporting immune health through adequate sleep, balanced nutrition, stress management, and regular exercise helps maintain healthy monocyte levels and effective immune function.
How this connects to other biomarkers
- Elevated Monocytes (monocytosis) with chronic inflammation, autoimmune disease, or chronic infection (TB, endocarditis) is common.
- Persistent monocytosis > 1 × 10⁹/L (see Monocytes (abs.)) with reduced cell counts elsewhere raises concern for chronic myelomonocytic leukemia (CMML — a slow-growing bone marrow cancer).
- Low Monocytes can occur with corticosteroid therapy, chemotherapy, or aplastic anemia (bone marrow failure).
How often should I test Monocytes?
Most adults benefit from yearly monocyte percentage testing as part of a CBC differential. Persistent elevation prompts your clinician's follow-up rather than a fixed retest interval.
At baseline / for screening: Once every 12 months from age 30 as part of a CBC with differential.
Included in
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