Laboratory Activity 5: BLOOD CELL C OUNT: HEMOCYTOMETRY(Manual) METHOD

Question 1

Blood cell counts determine the number of circulating blood cells (leukocytes, erythrocytes and platelets) present in (?) of whole blood.

Answer 1

1 uL or 1 mm3

Question 2

Though most clinical laboratories currently use (?) to speed testing time and improve accuracy, the leukocyte count may still be performed accurately by manual technique.

Answer 2

electronic cell counters

Question 3

A. Dilution:
1. Use (?) for WBC and RBC count respectively.
2. Make a capillary puncture. Discard the first (?)
3. (Do WBC count first) Hold Thoma pipette horizontally and draw blood exactly to the 0.5 mark.
4. (?) which adheres to the outside of the pipette.
5. Dip tip of pipette to appropriate diluting fluid and fill up to the mark ((?)for WBC pipette, (?) for RBC pipette), care being taken to avoid the introduction of bubbles into the bulb.
6. (?) into a figure of eight to mix.
7. Repeat (?) using RBC pipette.

Answer 3

WBC and RBC pipette

2-3 drops

Wipe off any blood

11; 101

Gently shake pipette

steps 3-6

Question 4

B. Charging the Counting chamber:
1. After mixing, expel the first (?) of the mixture from the Thoma pipet.
2. Prepare the hemocytometer by placing the coverslip on the (?).
3. Hold pipette as if it were a pencil. With the (?) the end of the pipette, allow one drop of diluted blood to fill one side of the chamber by capillary action. If the chamber is provided with V-slash, fill into the V-slash.
4. (?) the area. Avoid bubble formation, incomplete charging or overflow into the surrounding moat. Do steps 1-4 for both WBC and RBC pipettes.
5. Allow cells to settle for 2-3 minutes.

Answer 4

2 drops

transverse bars

index finger controlling

Completely fill

Question 5

WBC count
a. Locate the first W square of the counting chamber using (?) and count the white cells (round, nucleated cells) in all (?) Count the remaining WBC in the (?) other W squares.

Answer 5

LPO

16 squares.

3

Question 6

RBC count
a. Locate the first R square of the counting chamber using (?) and count the red cells (round, non-nucleated cells) in all (?). Count the remaining red cells in the (?) other R squares.

Answer 6

HPO

16 squares

4

Question 7

Note: Include cells that touch the (?) boundary lines.

Answer 7

top or left

Question 8

Cell count/mm3 =

Question 9

Report results in:

Answer 9

Cells/mm3 or Cells/uL
Cells x 10n/L ( x 109/L for WBCs & platelets; x 1012/L for RBCs)