Lab Worksheet #5: Red Blood Cell Count

Question 0

Blood is diluted with a/an (hypotonic/isotonic/hypertonic) solution for the preservation of the blood corpuscles.

Answer 0

Isotonic

Question 1

This is the number of red cells in 1 cu mm of blood.

Answer 1

Red cell count

Question 2

What are the characteristics of a good RBC diluting fluid?

Answer 2

Must:
Be an isotonic solution
Have a high specific gravity
Be easy to prepare
Be cheap
Be a good preservative
Have a buffer action
Not initiate the growth of molds

Question 3

Blood should be aspirated up to the ___ mark of the RBC pipette.

Answer 3

0.5

Question 4

By syringe aspiration, draw the diluting fluid up to the ___ mark with constant rotation of the pipette to ensure proper mixing of the blood and the diluting fluid.

Answer 4

101

Question 5

When aspirating the diluting fluid into the pipette, explain why constant rotation of the pipette must be done.

Answer 5

To ensure proper mixing of the blood and the diluting fluid.

Question 6

What is the dilution ratio between the blood and the diluting fluid in the pipette?

Answer 6

1:200 or 1/200 dilution

Question 7

What must be done if the diluting fluid goes beyond the 101 mark or if there is presence of bubbles inside the bulb?

Answer 7

Discard the mixture and start from the beginning making use of a dry clean pipette.

Question 8

This is also known as filling the counting chamber.

Answer 8

Charging

Question 9

How many drops of the diluted blood from the pipette must be discarded before charging the counting chamber?

Answer 9

5-6

Question 10

What is the angle of the pipette while charging?

Answer 10

30 - 35

Question 11

Overcharging can be readily observed by the presence of _____.

Answer 11

Fluid on the moats of the counting chamber.

Question 12

This can be readily observed by the presence of fluid on the moats of the counting chamber.

Answer 12

Overcharging

Question 13

Undercharging is observed by the failure to _____.

Answer 13

Cover the entire ruled area of the counting chamber.

Question 14

This is observed by the failure to cover the entire ruled area of the counting chamber.

Answer 14

Undercharging

Question 15

Air bubbles seen on the counting chamber indicates the _____.

Answer 15

Presence of moisture or dirt

Question 16

_____ seen on the counting chamber indicates the presence of moisture or dirt.

Answer 16

Air bubbles

Question 17

When finished filling the counting chamber (charging), let the pipette stand for ___ - ___ minutes to allow the RBCs to settle.

Answer 17

5 - 10

Question 18

Count theRBCs seen on the 5 tertiary squares designated as _____.

Answer 18

R squares

Question 19

The 5 squares, R squares, have an area of _____.

Answer 19

1/5 sq. mm.

Question 20

Count the RBCs on the first row of the smaller squares from (left to right/right to left).

Answer 20

Left to right

Question 21

RBCs that touch any of the lines on the top and left borders, even if they are outside the tertiary square, are (included/not included) in the count.

Answer 21

Included

Question 22

RBCs that touch any of the lines on the bottom and right borders, even if they are inside the tertiary square, are (included/not included) in the count.

Answer 22

Not included

Question 23

Record the count on each of the 5 tertiary squares making sure that the cell difference between two squares is ___ or less.

Answer 23

20

Question 24

(T/F) All counts must be done in triplicates.

Answer 24

F - duplicates

Question 25

What is the general formula for the computation of the number of blood cells / cu mm of blood?

Answer 25

No. of cells/cumm
= (total no. of cells counted)/(area X depth X dilution)
= (total no. of cells counted)/(1/5 X 1/10 X 1/200)

= cells counted X 10,000

Question 26

What is the normal RBC count value for males?

Answer 26

4.5 - 6.0 M/cumm

Question 27

What is the normal RBC count value for females?

Answer 27

4.0 - 5.5 M/cumm

Question 28

What is the normal RBC count value during late pregnancy?

Answer 28

3.0 - 5.0 M/cumm

Question 29

What is the normal RBC count value at birth?

Answer 29

7.0 M/cumm

Question 30

This refers to an increased RBC count reflecting in an increased RBC mass, a condition that leads to hyperviscosity.

Answer 30

Polycythemia