Final answer:
To estimate cell concentration using a hemocytometer, count the cells within the grid squares, calculate the average, and account for volume and dilutions. For white blood cells, count different cell types to determine their relative percentages.
Step-by-step explanation:
Estimating the Number of Cells/mL Using a Hemocytometer
To estimate the number of cells per milliliter using a hemocytometer, follow these steps:
- Place the prepared sample on the hemocytometer under a coverslip positioned at a specified height.
- Identify and count the number of cells within the etched grid squares of the hemocytometer.
- Calculate the cell concentration by averaging the count from multiple squares and adjusting for the sample's volume observed.
- Apply any necessary dilution corrections if the original sample was diluted prior to counting.
- Use staining methods like neutral red or trypan blue to distinguish between viable and non-viable cells when performing a viable cell count.
An example of cell counting is demonstrated with a Petroff-Hausser chamber, where if 10 cells are counted within a square of 0.000008 mL, the concentration is calculated as 1,250,000 cells/mL.
For a white blood cell count, identify and tally each cell until you reach a set number (e.g., 100 cells), then calculate the relative percentages of each cell type present.