Step 1: Understanding the Concept: Manual cell counting using a hemocytometer requires specific dilution factors to ensure that cells are spread out enough to be accurately counted without overlapping.
Step 2: Key Formula or Approach: The dilution factor is mathematically calculated using the formula: \(\text{Dilution Factor} = \frac{\text{Total Volume}}{\text{Sample Volume}}\).
Step 3: Detailed Explanation: For a total red blood cell (RBC) count, blood is drawn up to the 0.5 mark on the RBC pipette.
Next, the diluting fluid (such as Hayem's or Dacie's fluid) is drawn up to the 101 mark.
The bulb of the pipette holds a total mixing volume of 100 parts (from the 1 mark to the 101 mark).
The blood occupies 0.5 parts of this 100-part volume.
Therefore, the dilution factor is \(\frac{100}{0.5} = 200\), making it a 1:200 dilution.
For White Blood Cell (WBC) counts, the dilution is typically much lower, usually 1:20.
Step 4: Final Answer: The standard dilution factor for manual RBC counting using a pipette is 1:200.