2. What is hemocytometer?
Uses of hemocytometer?
Principle of cell counting using Neubauer's
slides
Common sources of error during the process of
Hemocytometery
3. Hemo: Blood
Cyto: Cell
Meter: Measurement/Counting
Thus , it is a device originally designed and
usually used for counting blood cells.
4.
5. Thick glass slides with two ruling areas on
center
Ruling areas are separated by H-shaped
trough.
Beyond trough, there are two raised arms to
support cover glass
lining is coated by shiny metal or rhodium.
Neubauer’s slide with a cover slip over it is
called Neubauer’s chamber.
6.
7.
8. Each scale is 3mm wide and 3mm long.
Depth of the chamber is 0.1mm.
The whole scale is divided into 9 big
squares.
Each square is 1mm long and 1mm wide.
9.
10.
11. The four corner squares are further divided
into 16 smaller squares and are used for
WBC counting.
Total 64 small squares are there which have
a dimension of
0.25mm x 0.25mm = 0.0625mm
12. Central square is divided into 25 medium
sized square and are separated by triple
line
The medium sized square are further
divided into 16 small square(tiny)
The four corner and central square are
used for cell count
13.
14.
15. Special cover glass with smooth surface
and even thickness
› Thickness= 0.3, 0.4, 0.5 mm
› Length= 16x22mm, 22x23mm
16.
17. Draw the cell suspension into pipette up to
100 μL
Draw 100 μL of Trypan blue (to differentiate live and
dead cells)
Load both chambers of the Neubauer's slide
by pipetting the suspension under the cover
slip.
18.
19. Now place the Neubauer’s chamber under
the microscope.
Focus must be
› 4X to see the general formation of slides
› 10X for WBC counting
› 40X for RBC/ platelets counting
20.
21.
22.
23.
24. Count the cells in
› 4 corner squares
› The center square
25.
26. Do not count cells
touching
› Bottom line
› Right line
29. Count cells in the five selected chambers of
cell count.
30.
31. 1. Average # of cell per square =
Total number of cells / Total squares
2. Dilution factor =
final volume/ volume of cell
3. Concentration of cells =
average # of cell / dilution factor
32.
33. Blood count:
› for patients with abnormal blood cells, where
automated counters don't perform well.
Sperm count:
34. Cell culture:
› when subculturing or recording cell growth over
time.
35. Errors in this process are of two main types
› False high count
› False low count
36. › Uneven distribution of cell
Improper mixing
Error in pipetting
› Error in calculation
› Blood taken from area of hemo
concentration
› Yeast, dirt and leukocyte are
counted as RBC
37. › Blood diluted with tissue fluid
› Undue delay in counting of cell
› Clumping of cell(AIHA)
› Uneven distribution of cell
› Faulty technique of counting
› Improperly standardized counting chamber