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

2. 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.

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

4. Smear Preparation

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

6. Blood smear under microscope

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

8. 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

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

10. 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

11. 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

12. Counting directions

13. Counting 100 cells Neutrophil = % Eosinophil = % Basophil= % lymphocyte = % Monocyte = %

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