LAB - WHITE BLOOD CELL (LEUCOCYTE) COUNTING

Introduction:

A white blood cell count estimates the total number of white cells. It is important in the diagnosis of disease especially when accompanied by a differential white cell count.

Two method to evaluate total number of leucocytes

1. Manual method
2. Automation technique

Reagents:

Dilution solution:

Tuerk dilution solution: 2% glacial acetic acid

®       Glacial acetic acid                  

®       Distilled water

®       Gentian violet

Principle:

Acetic acid will lyse RBC, so WBC only can be count.

Procedure:

1. Using a red blood cell Thoma pipette draw well mixed blood and fill till the 0.5 mark. Clean the tip of the tube.
2. Now draw WBC diluting fluid to the 11 mark which is 1:20 dilution.
3. Mix well for 3 minutes.
4. Discard the first three to four drops of mixture and gently fill in the mixture into the Neubauer chamber.
5. Under 10X magnification, scan to ensure even distribution.
6. Count the red blood cells using 40X objective in the 80 smallest squares as indicated in the diagram of the chamber.

Questions:

1. What are the factors that may occur for the wrong counting of white blood cells?
2. Define leucocytosis.
3. What is the normal white blood cell range for adults and babies?