Monocytes
Monocytes are large white blood cells (leukocytes) that play an important role in the immune system. They belong to agranulocytes and act as 'cleaners'—removing dead cells, microbes, and toxins from the body. After migrating into tissues, they transform into macrophages—active phagocytes.
Normal monocyte values:
- Absolute count: 0.1–0.6 × 10⁹/L
- Percentage of total white blood cells: 3–11%
Main functions of monocytes:
- Phagocytosis—engulfing and destroying bacteria, viruses, and fungi
- Clearing the site of inflammation from destroyed cells
- Stimulating other immune cells (lymphocytes)
- Participating in immune response formation and tissue repair
Increased monocytes (monocytosis) may occur with:
- Viral and bacterial infections (tuberculosis, syphilis)
- Parasitic diseases (malaria, toxoplasmosis)
- Autoimmune diseases (rheumatoid arthritis, systemic lupus erythematosus)
- Chronic inflammations
- Blood cancers (leukemia, lymphoma)
Decreased monocytes (monocytopenia) may be observed with:
- Severe infections leading to immune system exhaustion
- Postoperative or trauma conditions
- Bone marrow suppression (e.g., after chemotherapy)
- Use of glucocorticosteroids
Features:
- Monocytes activate in later phases of inflammation when cleaning damaged tissues is necessary.
- It is important to evaluate monocyte levels together with other leukocyte parameters (neutrophils, lymphocytes, etc.).
- Monocytosis with normal other leukocytes may indicate chronic infections or early recovery stages.
How to take the test:
- Blood is drawn from a finger or vein, fasting (preferably in the morning).
- Avoid stress and physical exertion for 24 hours before the test.