The differential leucocyte count or DLC is a relative proportion of different types of WBCs (leucocytes) expressed as percentages. There are five types of WBC cells (leukocytes) i.e., Neutrophils, Eosinophils, Basophils, Monocyte, and Lymphocyte.
When we calculate the percentage of these individual type of cells in whole WBC in relation to each other, then this process is called DLC or Differential leukocyte count.
A blood sample of a person is used to find out the DLC of his WBC cells. If the percentage of any individual type of WBC cells is lower or higher compared to the normal range then, this can be an indication of any infection.
The normal range of DLC is as follows (in Percentage)
- Neutrophils: 40 – 70%
- Lymphocyte: 15 – 40%
- Monocyte: 2 – 10%
- Eosinophils: 1 – 6%
- Basophils: 0 – 2%
The normal range of DLC per cubic millimetre
- Neutrophils: 2500 – 8000/mm3
- Lymphocyte: 1000 – 4000/mm3
- Monocyte: 100 – 700/mm3
- Eosinophils: 50 – 500/mm3
- Basophils: 25 – 100/mm3
The increased or decreased number of any type of leucocyte can be an indication of an infection, allergy, or symptoms of any specific disease. Here are some examples…
The increased number of Neutrophils called neutrophilia that is an indication of bacterial infection like pneumonia, abscesses, meningitis, UTI, etc.
The decreased number of Neutrophils called neutropenia is an indication of anemia, aplastic anemia, aleukemic leukemia.
The increased number of eosinophils called eosinophilia that is an indication of Parasitic infection, Allergic infection, Asthma, Rhinitis, Urticaria, Eczema, Dermatitis, etc.
The increased number of basophils called basophilia is an indication of acute allergic infection, an immediate type of hypersensitivity.
The increased number of monocytes called monocytosis is an indication of chronic infection like Tuberculosis (TB).
The increased number of lymphocytes called lymphocytosis that is an indication of viral infection as well as a chronic infection.