White Blood Cell Differential Count

Objectives To able to identify the different types of leucocytes under the microscope To practice the procedure for differential leucocytes counting To know normal values for the different white cell count To know the importance of DLC in the diagnosis of disease processes.

Definition The relative percentage of each type of white blood cells in peripheral blood. This experiment is a part of blood routine test.

Microscopic exam 10× (low fold): overall smear quality, agglutination or parasites 100× (oil Len): WBC Diff, RBC morphology

Observing direction: Observe one field and record the number of WBC according to the different type then turn to another field in the snake-liked direction *avoid repeat or miss some cells

Morphology of WBC in peripheral blood

normal peripheral blood smear

White blood cells There are three types of granulocyte named according to their staining characteristics in blood films. They are neutrophils,eosinophils and basophils. Agranular cells are divided into lymphocytes and monocytes.

Neutrophils 62% of total WBCs Diameter: 10-12 microns Cytoplasm: very pale blue Granules: staining (purple) Nucleus: dark purple blue 2-5 lobes

Neutrophils . neutrophilic because they owe their colour to uptake of both the acidic and the basic components of the stain

Eosinophil Diameter: 13-14 microns Cytoplasm : full of orange-red coarse granules Nucleus: blue 2 lobes like a pair of glass 2.3%

Basophil Diameter: 14-15 Cytoplasm: Granules: dark blue –black obscure nucleus Nucleus: blue 0.4%

Lymphocyte Diameter: small 7-9 large 12-16 Cytoplasm : rim, clear, pale blue Nucleus: purple red ,oval indented 30%

Normal lymphocytes Lymphocytes are the smallest WBC. They have large condensed nucleus, with a scanty pale blue cytoplasm.

Monocyte Diameter: 16-18(are the largest normal blood cells) Cytoplasm: The cytoplasm is abundant, sky blue in colour. Some have vacuoles in the cytoplasm. Nucleus: purple, large kidney shaped and slightly indented. 5.8%