Monocytes are white blood cells (B-Monos, L-Monos%)
White blood cells are an important part of the human immune system. They protect the body from attacks of bacteria, viruses, and parasites. Bone marrow produces five different types of white blood cells, one of which is the monocyte.

Monocytes are white blood cells (B-Monos, L-Monos%)
White blood cells are an important part of the human immune system. They protect the body from attacks of bacteria, viruses, and parasites. Bone marrow produces five different types of white blood cells, one of which is the monocyte.
Monocytes
- Monocytes are largest of the white blood cells.
- They are able to travel from blood to other tissues and differentiate into macrophages or phagocytes.
- White blood cells are an important part of the human immune system.
- The B-Monos test measures the amount of monocytes in the blood.
What are monocytes?
White blood cells are an important part of the human immune system. They protect the body from attacks of bacteria, viruses, and parasites. Bone marrow produces five different types of white blood cells, one of which is the monocyte.
Monocytes are largest of white blood cells. They make up an average of 3–8% of all the white blood cells. Monocytes are able to move from blood to tissues and act as phagocytes that break down pathogens and remnants of dead cells.
Reference values for monocytes
Reference levels may vary depending on the laboratory and the test analysis method. Puhti samples are taken and analysed at the laboratories of Mehiläinen.
B-Monos
Reference value for monocytes (B-Monos) in adult men and women is 0,2-0,8 xE9/l.
B-Monos test measures the amount of monocytes in the blood.
L-Monos%
Reference value for monocytes (L-Monos%) in adult men and women is 2-10 %.
L-Monos% test shows the relative percentage of monocytes in white blood cells.
L-Monos% value is calculated in connection with the leukocyte differential (B-Diffi) test in a complete blood count. B-Diffi should be done when the number of leukocytes in the blood is elevated.
Low monocyte level (monocytopenia)
Monocytopenia, a lower than normal monocyte count, can occur for example in the context of the following conditions and diseases:
- Aplastic anemia
- Leukemia
- Severe burns
- Rheumatoid arthritis
- Systemic lupus erythematosus
- HIV infection
- Vitamin B12 deficiency
- Radiation therapy
High monocyte level (monocytosis)
Monocytosis, a higher than normal monocyte count, can occur for example in the context of the following conditions and diseases:
- Hematological diseases
- Infections such as tuberculosis, viral infections, malaria, and syphilis
- Autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis, and inflammatory bowel diseases
- Sarcoidosis
- Some cancers
- Heart attack
- HIV infection
- Depression
- Childbirth
- Obesity
- Severe pneumonia
- Liver disease due to alcoholism
