This document discusses techniques for counting white blood cells (WBCs) and red blood cells (RBCs) using an improved Neubauer chamber. The chamber has a ruled area of 3x3 mm divided into large and small squares. WBCs are counted in the four corner large squares, each containing 16 small squares. RBCs are counted in the central large square containing 25 small squares. The techniques calculate WBC and RBC concentrations per mm3 of blood based on the cell counts within the squares and known volumes.

1. CELL COUNTING
DR.MANJULA MBBS MD (PATHOLOGY)

2. IMPROVED NEUBAUER CHAMBER
RULED CHAMBER AREA
RAISED EDGES

3. IMPROVED
NEUBAUER CHAMBER

4. RULED CHAMBER AREA = 3 X 3 mm
9
large
squares,
each
measuring
1
x
1
mm
2
WBC are counted in 4 corner squares, each corner
square has 16 small square, each measuring 1/16 mm2
RBC
are
counted
in
central
square
which
has
25
small
squares,
each
measuring
1/25
mm
2

5. WBC COUNTING TECHNIQUE
• Volume of one large square = 1 X 1 X 1/10 mm3
• Volume of four large square = 1 X 1 X 1/10 X 4 mm3
= 2/5 mm3
• Assume that WBC in four large square as N
• 2/5 mm3 of blood contain, WBC = N X dilution factor
• 1 mm3 of blood contain, WBC = N X 50

6. RBC COUNTING TECHNIQUE
• Volume of one small square = 1/5 X 1/5 X 1/10 mm3
• Volume of five small square = 1/5 X 1/5 X 1/10 X 5 mm3
= 1/50 mm3
• Assume that RBC in 25 small square as N
• 1/50 mm3 of blood contain, WBC = N X dilution factor
• 1 mm3 of blood contain, RBC = N X 10.000