This document provides information about performing a red blood cell count. It discusses that red blood cells are biconcave discs around 8 micrometers in diameter. It describes how to perform a manual red blood cell count using a Neubauer chamber, diluted blood sample, and microscope. The steps include preparing a 1:200 dilution, filling the chamber, focusing on cells with the microscope, and counting cells within a specified area. The normal red blood cell count ranges for adults, newborns, and children are provided. Decreased red blood cell counts can indicate anemia, while increased counts can be seen with conditions like polycythemia or dehydration.

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