1. By: Shefaa Adel Hejazy.
Umm Al-Qura University, Makkah.
Faculty of Medical Sciences. Hematology Dept.
1st Semester 1433/2012

2. o
RBC is a flexible cell, biconcave disc in shape, and around
8 µm in diameter.
o
The number of red cells per volume of blood, measured in
microliters (µL) or cubic millimeters (mm3)

3. Screening:
Follow up:
-Health maintenance
-Response to ttt
-NSAIDs
-Chronic Anemia
To assess
degree of ..
Anemia and blood
loss

4. Counting of RBCs can be performed either:

Automated Method: (Electronic hematology cell counter, e.g.
COULTER)
OR

Manual Method: (visual using a microscope and counting
chmber), which is a cumbersome and less accurate.

5. o
The solution used for red cell count is Isotonic with RBCs;
doesn’t lyse leukocytes.
o
Leukocytes are normally too few which can be identified easily
and won’t be interfered with erythrocytes count.

6. o
Reagents and instruments:
1. Neubauer Chamber (Haemocytometer) & coverslips.
2. RBC diluting fluid/solution.
Consists of 3.2 g of Na-citrate and 1.0 ml of formaldehyde solution
made up to 100 ml with D.W.
o
Sample:

7. Improved Neubauer Chamber

8. o
A thick glass slide with H shaped moats in it.
o
The area between two lines of H (center) is 0.1 mm in depth.
o
Moat prevents mixing of 2 samples on either side of chamber.

10. o
Prepare a plastic tube (labeled).
o
Prepare 1:200 blood dilution (4 ml of diluent + 20 µl Blood).
o
So, add diluent to the tube. Mix the sample (5 times); then
aspirate 20µl and transfer to the tube and mix.
o
Clean the Haemocytometer and coverslip with 70% ethanol
followed by D.W &Leave to dry.
o
Place a coverslip on the Neubauer chamber.

11. o
o
Then, fill the chamber with the diluent (10 microliter) in each
side.
Leave chamber in humidity (petri-dish with wet filter paper) for
1-2 min. !?
o
Condenser slightly lowered. Iris diaphragm should be almost
closed.
o
Place chamber on microscope stage. Start with 10X to focus;
then with 40X count RBCs.

12. o
RBCs should be counted in the central square of the
chamber.
o
Select 5 small squares (One at each corner and one in the
center).

13. W
W
RBC
W
W

14. 25 small
Squares = 1
mm.sq
W
3 mm.sq
R

15. Central large square
RBCs
WBCs

16. Count all cells in specified squares, and multiply by the proper conversion
factor; the number of cells per cubic millimeter can be determined.

17. o
Count all cells within 16 squares and those lying on middle lines,
EXCEPT …

18. RBCs (1012/L) = No. of RBCs counted X Dilution X 106
Volume (µl)
o
Dilution = 200
o
Depth of the chamber = 0.1 mm.
o
Volume of 5 small squares = 0.02 µl
So,
Red cell count/ liter = N x 0.01 x 1012
i.e. RBCs= N x 1012/L

19. o
Diluent should be correct.
o
No overflow in the moats.
o
No air bubbles and debris in the chamber area.
o
No scratches in the ruled area of the chamber.
o
Pipettes used must be clean and dry.

20. Age group
RBC count
Adult Male
4.7 – 6.1 X 1012 /L
Adult Female
4.2 – 5.4 X 1012 /L
Newborn
4.4 -5.8 X 1012 /L
Infant/ children
3.8 – 5.5 X 1012 /L

21. 
Decreased value (
RBCs)
1.
Anaemia: due to Blood loss, production of cells, destruction
of cells, and dietary insufficiency.
2.
Diseases which affect the Bone Marrow such as:
i.
ii.
iii.
Leukaemia
MM
Hodgkin’s Lymphoma
1.
Subcutaneous bacterial endocarditis
2.
Rheumatic fever

22. 
Increased value ( RBCs)
1.
Polycythaemia vera
2.
Secondary polycythaemia, e.g. smokers, high altitude,
cyanotic heart defects, and COPD.
3.
Dehydration
4.
Acute poisoning
5.
Severe diarrhea

23. sahejazy@uqu.edu.sa