The McGill Physiology Virtual Lab

Blood Laboratory

Blood cell indices > Differential white cell count
  Mammalian blood contains 5 different types of white blood cells which can be distinguished by staining with dyes. The Difquik kit provides a rapid method for this purpose. In this test you will be determining the percentages of each type of leukocyte present in the blood.
Neutrophils, eosinophils and basophils are described collectively as granulocytes. They are distinguished by the nature of the granules in their cytoplasm, and generally have small, multilobed nuclei. The 2 other types of white cells are lymphocytes and monocytes and are described collectively as agranulocytes.


Neutrophils have nuclei with several lobes and fine purple granules in their cytoplasm. Their are termed neutrophil, because their granules are not very amenable to staining with either acidic or basic dyes. They are the most numerous of the leukocytes, making up 50-70%.

Eosinophils feature large granules that can be stained bright red with an acidic dye - e.g. eosin. They most often have bi-lobed nuclei. They make up about 1-4% of the leukocytes

Basophils have multi-lobulated nuclei and large granules which stain blue with basic dyes. They occur quite seldomly (less than .1%).


Lymphocytes can be large or small. They are spherical and have a very large nucleus taking up most of the cytoplasm. The cytoplasm has no granules. Lymphocytes represent 20-40% of all leukocytes.

Monocytes are large cells. They have large indented nuclei, often kidney-shaped and very fine cytoplasmic granules. They make up 2-8% of the leukocytes.
Deviations of different white cell counts from the normal values often indicate a diseased state. Neutrophilia (high neutrophil count) often signals localized infections such as appendicitis; eosinophilia (high eosinophil count) may indicate allergic conditions or invasion by parasites such as Trichinella; lymphocytosis (high lymphocyte count) may be seen in some viral infections; neutropenia (low neutrophil count) occurs in typhoid fever, measles or infectious hepatitis, and eosinopenia (low eosinophil count) may be produced by an elevated secretion of corticosteroids (in states of stress).

To practice with the differential white cell count, click here