White blood cells or leukocytes are cells
of the immune system which defend the
body against both infectous disease and
The white blood cells have a rather short
life cycle, living from a few days to a few
White cell count (WBC) is the total
number of leukocytes in a volume of
blood, expressed as thousands/µl.
Using diluent that destruct all
blood cell leaving only WBCS
Equipment and reagents:
1. Hemacytometer and cover slip.
2. Glass pipette.
1. Turks' solution: which is formed of:
Glacial acetic acid
EDTA- anticoagulated blood
1. Blood dilution:
Add 10 µl of well mixed blood sample to 200µl
of the diluting reagent.
The dilution factor is 1:20.
2. leave the mix for 2 mins. till complete lyses
2- Charging :
Charge the hemocytometer
between couver slip and
the counting chamber.
Leave the cells to settle down.
Count the WBCs in 4 1ry squares.
Count in L- shape manner.
Count under medium power.
Leukocytes µl of blood =
No. of cells x depth factor x dilution factor =
no. of square counted
Leukocytosis is a condition characterized by
an elevated number of white cells in the
blood, which is usually due to:
Bacterial infection such as appendicitis, tonsillitis,
ulcers and urinary tract infection
Leukopenia is a condition characterized
by a decreased number of white cells in
the blood, which is usually due to:
Viral disease such infectious hepatitis.
Some bacterial infections such as brucellosis.
Radio therapy and chemotherapy.
In case of counting WBCs and RBCs in poultry
or fish blood, one is preferred to use Natt
and Herrick solution.