WET FILM
PREPARATION
In
hematology, it is most important to know that wet films are also made for
hematological analysis. Wet
films are made in sickling test analysis and in rough estimation of platelets
and white blood cell.
WET PREPARATION
FOR WHITE BLOOD CELL COUNT
Materials Used:
·
Test
tube
·
Improved
Neubauer counting chamber
·
Blood
sample
·
Automatic
pipette
·
Cotton
wool
·
Cover
slip
·
Turks
solution
Procedure:
·
1:20
dilution of the blood is prepared in the diluting fluid (Turk solution) in a
test tube.
·
The
improved Neubauer counting chamber is charge by moisturizing the chamber a
little and sliding up by the cover slip to form a Newton ring.
·
With
the help of the automation pipette filler, the grids of the charged improved
Neubauer counting chamber is filled with the diluted sample and allowed to
settle.
·
Precaution
is to be taken to ensure that the grid is not over filled
·
The
cells are allowed to settle in a moist chamber (e.g. a cotton wool -moist petri
dish with cover) for 3-5 minutes (Ochei and Kolhatkar, 2007).
WET PREPARATION
FOR PLATELET COUNT
Materials Used:
·
New
improved Neubauer counting chamber
·
Test
tube
·
Automatic
pipette
·
Ammonium
oxalate (diluents)
Procedure:
·
A
dilution of 1:200 of the whole blood and the diluent is made in a test tube.
·
The
improved Neubauer counting chamber is charged
·
With
the automatic pipette, fill the grids of the counting chamber.
·
Allow
the platelets to settle in a moist chamber for 2-3 minutes(Ochei and Kolhatkar,
2007).
GENERAL
PRECAUTIONS TAKEN WHILE MAKING FILMS IN HEMATOLOGY:
1.
The
slide must be well cleaned, grease-free and dust free
2.
The
spreader must be smooth
3.
Ensure
that the surface of the slide is water free
4.
Do
not overfill the grid of the improved Neubauer counting chamber
5.
Do
not fill the two grids of the improved Neubauer counting chamber, only one grid
is to be filled
6.
Ensure
neat working environment is maintained.
7.
Label
the slide properly for identification and good laboratory management
8.
2
smears at least, must be made for a particular sample to ensure accuracy and
good result (Ochei and Kolhatkar, 2007).
WET PREPARATION FOR SICKLING TEST
Materials used:
·
A
fresh anticoagulated blood sample
·
A
normal blood sample for control
·
A
freshly prepared solution of 2% sodium metabisulphite.
·
10ml
distilled water
·
Test
tube
·
Pasture
pipette
·
Glass
slide
·
Cover
slip
·
Vaseline
Procedure:
·
Dissolve
0.2g of 2% sodium metabisulphite in 10ml distilled water
·
Add
0.5ml of whole blood to 0.5ml 2% sodium metabisulphite in a test tube
·
Mix
thoroughly and place a drop on a glass slide, cover with coverslip. Seal all
the four edges with Vaseline.
·
Leave
at room temperature for 1hour
·
Observe
the red cell morphology under the microscope.
·
Proceed
with the control in the same way (Ochei and Kolhatkar, 2007).