WBC diluting fluid is used to perform the WBC(leucocyte) count or white blood cell count
Principle of WBC Diluting Fluid
WBC diluting fluid is used to perform the WBC( leucocyte) count.
The blood specimen is diluted 1:20 (20:380 in some laboratories) in a White blood cell pipette with the diluting fluid, and the cells are counted under the low power of the microscope using a counting chamber.The number of cells in undiluted blood is reported per cumm( μl) of the whole blood.
Composition of WBC Diluting Fluid
|Ingredients||Grams or Mass|
|Glacial acetic acid||2.00 ml|
|Gentian Violet (1% w/v)||1.00 gm|
|Distilled water||97.00 ml|
|Final pH ( at 25°C)||2.2±0.2|
Appearance of WBC Diluting Fluid
It is a clear solution having a purple colour
How to Count White blood cells using WBC diluting fluid
- Draw the EDTA anticoagulated blood to 0.5 mark on the capillary end of the WBC pipette.
- Carefully wipe excess blood outside the pipette using cotton.
- Draw the diluting fluid up to 11 marks.
- Mix the contents in a pipette and after 5 minutes, discard a few drops, fill the counting chamber and allow the cells to settle for 2- 3 minutes.
- Focus on 1 of the ” W” marked areas( each with 16 small squares) by turning the objective to 10X low power
- Count cells marked in all 4 ” W” corner squares.
How to count and calculate White blood cells
Number of WBCs/cumm(µl)of whole blood =No. of WBCs counted X Dilution /Area counted X Depth of fluid where,Dilution=20; Area counted= 4x1sq.mm=4sq.mm ; Depth =0.1mm(constant)
No.of leucocytes / cu mm(µl) of whole blood = No.of cells counted X 20 / 4 X 0.1
WBC Normal range
|Age||Normal White blood cell Count range(cell/cumm of blood)|
|At Birth||10.000 – 25000|
|Infant||8000 – 15000|
|4-7 years||6000 – 15000|
|8 – 18 years||4500 – 13500|
|Adult||4000 – 10.000|
|Pregnancy||12000 – 15000|
- Textbook of Medical Laboratory Technology; Praful B. Godkar
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