TOTAL LEUCOCYTE COUNT
Number of white blood cells in 1 µl or
1 cubic mm of blood
Age group Cells / cu.mm
At Birth 18,000 ± 8000
1 yr 6,000 - 15000
2 – 6 yr 5,000 - 15000
Pregnancy Upto 15,000
TLC > 11,000/MM3
Malignancy like leukemia
a) Neubauer’s slide
b) Cover slip
c) RBC pipette
d) WBC pipette
It is the name given to a thick glass slide .
In the centre of the slide, there is an H- shaped
On the two sides of the central horizontal bar,
there are scales for counting the blood cells
The depth of the scales is 1/10mm or 0.1mm.
Neubauer’s slide with a cover slip over it, is
called a Neubauer’s chamber
Four corner squares are meant for WBC
Total = 64 small squares
It has a white bead
It has graduations upto mark 11
WBC (TURK’S) DILUTING FLUID:
It is prepared as follows:
a) Glacial acetic acid: 2.0 ml
b) 1 % (w/v) gentian violet: 1.0 ml
c) Distilled water: 97 ml
The glacial acetic acid lyses the red cells while
the gentian violet slightly stains the nuclei of
The blood specimen is diluted 1:20 in a WBC
pipette with the diluting fluid.
The cells are counted under low power of the
micro scope by using a counting chamber.
The number of cells in undiluted blood are
reported per cu mm (µl) of whole blood
Draw blood up to 0.5 mark of a WBC pipette.
Carefully, wipe excess blood outside the pipette
by using cotton.
Draw diluting fluid up to 11 mark.
Mix the contents in the pipette and after five
minutes by discarding few drops, fill the
counting chamber and allow the cells to settle
for two to three minutes.
4X to see the general formation
10X for WBC counting
Do not count cells touching
This is to avoid double counting.
0.5 part of blood is mixed in 10 parts of fluid
So, 1 part of blood is in 20 parts of fluid
Thus, dilution factor for WBC counting is 20.
No. of cells counted x dilution
WBC count (per cubic mm) = ----------------------------------------
Volume of chamber
N x 20
4 x 0.1
= N x 50 cells / cubic mm
Coulter – Automated haemanalyser
Easy and rapid method
Very large number of cells are counted rapidly
High level of precision
Nucleated RBCs are counted as leucocytes
Platelet clumps counted as leucocytes
OTHER USES OF NEUBAUER CHAMBER
CSF cell count