PLATELET COUNT - Students PDF
Uploaded by
ScribdTranslationsPLATELET COUNT - Students PDF
Uploaded by
ScribdTranslationsPLATELET COUNT
FOUNDATION
For the platelet count in the chamber, the problematic blood is diluted.
in an appropriate liquid and, subsequently, is deposited in the chamber of
count, where the cells present in one of the squares are counted
from one of the reticula.
MATERIAL
. Test tube, preferably made of plastic.
. Micropipette.
. Gas.
. Counting chamber, with an improved Neubauer-type graticule.
. A cover slip, preferably of the specially type
designed for use in camera counts.
. A microscope.
. Petri dish.
. Filter paper.
Reagents
. Distilled or deionized water.
. Dilution liquid. There are several solutions that can be used.
for the platelet count. This liquid also acts
diluting the sample, breaks the red blood cells, prevents aggregation of
the platelets among themselves and their adhesion to other elements, and facilitates
the visualization of platelets by making them refringent.
Sample:
. Capillary blood or recently extracted venous blood and
collection in a tube with EDTA.
TECHNIQUE
Make a 1/100 dilution of the blood in a test tube.
Page 1 of 3
Take 20μl of blood and dilute it in one of the tubes that contain.
the diluent liquid (1.98 ml), with this we will achieve dilution of the
show at 1/100.
2. Load the counting chamber with the blood dilution.
3. Place the loaded counting chamber inside a chamber.
humid. A humid chamber can be prepared with a Petri dish.
closed, inside which a filter paper soaked in
water. Let the loaded counting chamber rest for 15
minutes. The wet chamber prevents the drying out of the dilution of
blood present in the counting chamber and the resting ensures the
complete sedimentation of all platelets.
4. Place the counting camera on the microscope stage.
5. Focus one of the reticles of the counting chamber with a
low magnification objective (10x). With this objective, one observes the
homogeneity of cellular distribution, such that if it is not
satisfactory, a new dilution of the sample is carried out.
6. Focus one of the large squares of the grid (for example, the
central), with the goal of a medium increase (40x). If a
normal microscope, the platelets are better visualized by positioning the
slightly low capacitor.
7. Count the total number of plates deposited in that square
big.
READING OF RESULTS
Platelets are observed as rounded or oval-shaped corpuscles.
very small in size and very refractive. One must ensure not to
confusing them with leukocytes, erythrocyte debris, and especially with
dust particles.
To calculate the number of platelets per mm3of blood, it is applied the
next formula:
PLT/mm3= P x V x D = P x 1.000
PLT/mm3Number of platelets per mm3of blood.
P = Number of platelets counted in 1 large square.
Page 2 of 3
Volume correction (10).
D = Dilution correction (100).
If the obtained platelet count is suspiciously low,
A smaller dilution of the sample is made and the platelets are counted.
deposited in various large squares.
On the contrary, if the obtained platelet count is suspiciously,
very high, a greater dilution of the sample is performed.
This implies an adjustment of the calculations needed to obtain the
PLT/mm3and aims to confirm the obtained results.
WORKSHEET
1. RESULTS. MAKE A DRAWING OF THE RETICULUM INDICATING
THE AREA WHERE YOU HAVE DONE THE COUNT OF
PLATELETS AND THUS THEIR NUMBER.
Number of platelets per mm3of blood:..........................
2. EVALUATION OF RESULTS
The number of platelets obtained is:
Low
Normal
High
Page 3 of 3