When counting RBCs and WBCs do you use a concentrated blood sample hemocytometer?
When counting red blood cells (RBCs) and white blood cells (WBCs), a diluted blood sample is used in a hemocytometer, not a concentrated sample. Concentrating the blood sample would lead to inaccurate cell counts. Here's the process of counting RBCs and WBCs using a hemocytometer:
Red Blood Cell Count (RBC)
1. Preparation of Diluted Blood Sample:
- Dilute the blood sample in a specific dilution fluid, usually with a dilution ratio of 1:200 for RBCs.
- Mix the diluted blood thoroughly.
2. Loading the Hemocytometer:
- Place a coverslip on the hemocytometer, ensuring that the edges are sealed to create a counting chamber.
- Introduce a small amount of the diluted blood sample onto the hemocytometer using a capillary tube or a micropipette.
3. Counting Red Blood Cells:
- Use a microscope to visualize the cells in the counting chamber.
- Focus on the gridded area of the hemocytometer, which is divided into large squares and smaller squares.
- Count the number of RBCs within the specified squares according to the specific counting rules (e.g., counting cells touching the top and left lines and excluding those touching the bottom and right lines).
4. Calculation:
- Multiply the counted number of RBCs with the appropriate dilution factor and chamber depth to obtain the RBC count per unit volume (usually cells/μL).
White Blood Cell Count (WBC)
1. Preparation of Diluted Blood Sample:
- Prepare a separate diluted blood sample, usually with a dilution ratio of 1:20 for WBCs.
- Mix the diluted blood thoroughly.
2. Loading the Hemocytometer:
- Repeat the same process as for the RBC count, placing a coverslip on the hemocytometer and introducing the diluted blood sample.
3. Counting White Blood Cells:
- Use a microscope to visualize the cells in the counting chamber.
- Focus on the gridded area of the hemocytometer and count the number of WBCs within the specified squares.
- Differentiate between different types of WBCs if required (e.g., neutrophils, lymphocytes, monocytes, etc.).
4. Calculation:
- Multiply the counted number of WBCs with the appropriate dilution factor and chamber depth to obtain the WBC count per unit volume (usually cells/μL).
It's crucial to follow the specific instructions and guidelines provided by the manufacturer of the hemocytometer and the laboratory protocol to ensure accurate cell counting.