Monocytes are cellular components of the blood. They are a subset of leukocytes (white blood cells). When they leave the circulating blood, they develop into macrophages scavenger cells).
Monocytes have a diameter of about 12-20 µm. This makes them the largest cells in the circulating blood.The life span of circulating monocytes is 1-3 days; as macrophages they have a life span of 2-3 months.
They are counted as part of both the specific and non-specific cellular immune systems.
Monocytes are determined as part of the differentiation of leukocytes (see “Differential blood count” below).
The procedure
Material needed
- 4 ml EDTA blood (mix well!); for children, at least 0.25 ml.
Preparation of the patient
- Not necessary
Disruptive factors
- None known
Indications
- Infections
- Autoimmune diseases
- Granulomatous diseases of the lung
- Malignant (malignant) neoplasms
Normal values
Age | Absolute values | Percentage(of total leukocyte count) |
Infants | 630-3,000/μl | 630-3,000/μl |
Children | 80-720/μl | 1-6 % |
Adults | 200-800/μl | 2-10 % |
Interpretation
Interpretation of elevated values (monocytosis).
- Physiologic: pregnancy, after extreme sports
- Infections
- Bacterial infections
- Brucellosis (extremely rare)
- Endocarditis lenta
- Paratyphoid fever
- Tuberculosis (TB)
- Syphilis
- Viral infections
- Dengue fever (severe form)
- Hantavirus infection
- Infectious mononucleosis (EBV infection)
- Morbilli (measles)
- Parotitis epidemica (mumps)
- Rocky mountain spotted fever (rocky mountain spotted fever; rare).
- Varicella (chickenpox)
- Parasitic infections
- Malaria (severe form)
- Leishmaniasis (Leishmania)
- Trypanosomiasis (trypanosomes; sleeping sickness).
- Bacterial infections
- Convalescence / recovery phase after acute infections.
- Autoimmune diseases
- Polymyalgia rheumatica
- Rheumatoid arthritis
- Giant cell arteritis (formerly arteritis temporalis).
- Sarcoidosis
- Scleroderma (rare)
- Systemic lupus erythematosus (SLE)
- Granulomatous diseases of the lung: granuloma formations.
- By inorganic and organic dusts, e.g., berylliosis, silicosis, exogenous allergic alveolitis.
- By diseases such as sarcoidosis, histiocytosis X, granulomatous vasculitides.
- Malignant neoplasms
- Chronic myeloid leukemia (CML).
- Malignant lymphoma
- Myelomonocytic leukemia
- Hodgkin’s disease
- Metastatic tumors
- Drugs