Exp 05

Total White Blood Cell Count [100x]¶

1. Draw blood till 0.5 Mark in Thoma Dilution Pippete (with the white bead)
2. Draw the RBC dilution flood up to 11 mark. Homogenize the sample for 2-3 min.
3. Discard the first few drops of sample present at the tip as it only contains the dilution fluid.
4. Charge the haemocytometer with the sample by gently touching the tip of the pippete of the counting platform. In contact with the edge of the cover slip, small amount of fluid will automatically by surface tension and capillary action.
5. Wait for 5mins.

6. The WBCs are counted in 4 corners under 10x low power objective. You will see 16 boxes in each corner, apply the L - Rule.

7. Total number of WBC's per MicroLiter is given by (D*N)/V

8. Dilution Factor is 10, Volume is 0.4 MicroLiter.
9. Total Number of WBCs = N * 50 Cells

Normal range of WBC in a human body is 5000 - 10000 cells/mm^3.

Common Reasons for False High Results:¶

• Dilution Fluid taken below mark (Insufficient Dilution)
• Overloading

Common Reasons for False Low Results:¶

• Excessive Dilution
• Insufficient Loading

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