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
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. Multilobed nucleus
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 N M E L Neutrophil = % Eosinophil = % Basophil= %
lymphocyte = %
Monocyte = %

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