DIFFERENTIAL LEUCOCYTE COUNT (DLC) HMIM BLOCK 224 Dr. SYED AFTAB OMAR AlMaarefa College

Objectives Describe the morphological characteristics of each white blood cell. Identify the different blood cells in the blood smear. Differentiate between neutrophils, eosinophils, basophils, monocytes and lymphocytes. Describe the functions of each WBCs. List the conditions in which their count increases and decreases.

Apparatus & materials Microscope Glass slides Lancet Alcohol swab Leishman’s stain Distilled water

Smear Preparation

Types of White Blood Cells Are leukocytes There are five types of WBCs in two categories: Granulocytes Neutrophils Eosinophils Basophils Agranulocytes Lymphocytes Monocytes

Blood smear under microscope

Neutrophils Size – 10-14 µm. Multilobed nucleus Light purple (neutral) granules Other names is Polymorphonuclear leukocyte Phagocytic in function Normal range = 50% - 70% Elevated in acute bacterial infections

Eosinophils Size – 10-15 µm Coarse red color granules Bi-lobed nucleus Defend against parasitic worm infestations Normal range 1% - 6% Elevated in parasitic worm infections and allergic reactions

Basophils Size – 10 – 15 µm Bilobed nucleus Deep blue granules covering the whole nucleus Release histamine Release heparin Normal range- Less than 1%

Monocytes Largest of all blood cells Size – 12 – 20 µm Spherical, kidney-shaped, oval or lobed nuclei No visible granules May leave bloodstream to become macrophages Normal range - 2% - 10% Phagocytize bacteria, dead cells, and other debris Increase count – in chronic infections eg. Tuberculosis

Lymphocytes Size – 7-9 or 10-15 µm Slightly larger than RBC Large spherical nucleus surrounded by thin rim of cytoplasm No visible granules Normal range -20% - 40% T cells and B cells Both important in immunity B cells produce antibodies T cells involved in cell mediated immunity Increased count is seen in viral infections, chronic infections

Counting directions

Counting 100 cells N M E L Neutrophil = % Eosinophil = % Basophil= % lymphocyte = % Monocyte = %

WBC count decreases in bone marrow suppression due malignancy, radiation, chemotherapy or any genetic disorder