Monocytes

Complete Blood CountImmunity & InflammationBlood

Monocytes are the largest white blood cells, comprising 2-8% of the WBC count. They circulate in blood for 1-3 days before migrating into tissues where they differentiate into macrophages (tissue scavengers) or dendritic cells (antigen presenters). They are key players in both innate immunity and the bridge to adaptive immunity.

Why it matters: Elevated monocytes (monocytosis) often indicate chronic infections (tuberculosis, endocarditis), inflammatory conditions, or recovery from acute infection. Persistent monocytosis can also signal myeloproliferative disorders (CMML). Monocytes drive atherosclerosis by entering arterial walls and becoming foam cells.

Reference Range
0.2 – 1.010x9/L
0.2
1LowNormalHigh
Symptoms of Low Monocytes
Typically without noticeable symptoms
Symptoms of High Monocytes
Fatigue
Symptoms of a chronic infection or inflammatory condition
What Moves It

May increase with:

Chronic infections (TB, endocarditis, fungal)
Chronic inflammatory diseases
Recovery from acute infection
Autoimmune disorders
Chronic myelomonocytic leukemia (CMML)
Post-splenectomy

May decrease with:

Acute stress (cortisol redistributes monocytes)
Bone marrow suppression
Aplastic anemia
Hairy cell leukemia
Associated Conditions
TuberculosisChronic infectionsCMMLAutoimmune diseaseAtherosclerosis
Related Markers
White Blood CellsCRPESR
Common questions

What is Monocytes?

Monocytes are the largest white blood cells, comprising 2-8% of the WBC count. They circulate in blood for 1-3 days before migrating into tissues where they differentiate into macrophages (tissue scavengers) or dendritic cells (antigen presenters). They are key players in both innate immunity and the bridge to adaptive immunity.

What might a high or low Monocytes mean?

Elevated monocytes (monocytosis) often indicate chronic infections (tuberculosis, endocarditis), inflammatory conditions, or recovery from acute infection. Persistent monocytosis can also signal myeloproliferative disorders (CMML). Monocytes drive atherosclerosis by entering arterial walls and becoming foam cells.

What is the typical reference range for Monocytes?

The general-population reference range shown here is 0.2 – 1 10x9/L. Reference ranges describe the general population and are not a personal target — discuss your results with your physician.

What can affect Monocytes?

It may be higher with: Chronic infections (TB, endocarditis, fungal), Chronic inflammatory diseases, Recovery from acute infection, Autoimmune disorders, Chronic myelomonocytic leukemia (CMML), Post-splenectomy. It may be lower with: Acute stress (cortisol redistributes monocytes), Bone marrow suppression, Aplastic anemia, Hairy cell leukemia.

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