TWBCs Count
White blood cells are known to be the Human body defense mechanism, which fights pathogens and foreign antigens. in order to know the exact number of the white blood cells we must perform TWBCs Count Test.
There are two ways to do the test
1. Automated (Using CBC Machine)
2. Manual (Using Haemocytometer *Counting Chamber*
in this Article we are Talking about the manual TWBCs Count Technique
Principle
We us Glacial Acetic Acid (GAA) and mix it with blood to brakdown RBCs, Platelets and the Membrane of WBCs . The only thing that remains is the Nucleus of WBCs which is exactly we count, where we can see them under microscope as small Shiny Round Particles.
Equipments
- Glacial Acetic Acid (GAA)
- Counting Chamber (Hemocytometer)
- small Tube
- Cover Slide
- Pipette
- Tips
- Rak
Sample Type
for this test we use EDTA Whole Blood
Procedure
Sample Preparation
- in clean dry tube Take 380 μL from Glacial Acetic Acid (GAA)
- using pipette Add 20 μL from the whole blood to the GAA Tube (Makes sure to mix sample and remove excess amount of blood from the tips by swaping it with gauze or cotton.
- mix well and incubate for about 2 mins to make sure all RBC are Hemolysed.
Test Procedure
- Prepare the Haemocytometer by fixing the Cover slide on it using D.W
- mix the mixure of sample and GAA well and dispense one drop into the hemocytometer
- put the hemocytometer in microscope stage and wait for 1 min so WBCs Sttle down.
- using x10 Microscope Lens start counting the 4 corners of the chamber as shown Below
- When counting make sure to count all the cells inside the 16 small squares in every corner
- when you see cells touching the line of the caounting area select two sides to cont and two sides not to count as mentioned above
- after calculating the 4 corners of the chamber now comes calculation step
Calculations
Calculation formula as follows :
- Dilution factor = 20
- Area Counted = 4
- De[th = 0.1 mm
Normal Range and unit
Normal Range for WBCs Count is = 4 – 11 x 103
Unit: Cell/ Cu mm