Introduction
Table of Contents
Counting red blood cells (RBCs) using a Neubauer chamber, also known as a hemocytometer, is a manual technique commonly used in hematology. Here’s a step-by-step guide on how to perform a manual RBC count using a Neubauer chamber:
Equipment and Materials
- Neubauer chamber
- Microscope
- Coverslip
- Hemocytometer pipette
- Diluting fluid (usually a diluent like Hayem’s or normal saline)
- Blood sample
Procedure
- Prepare the Dilution:
- Mix a small amount of blood with a diluting fluid. The dilution factor will depend on the specific protocol and the expected concentration of RBCs. A common dilution factor is 1:200.
- Load the Hemocytometer:
- Using a hemocytometer pipette, carefully load a small amount of the diluted blood into the hemocytometer. Allow the fluid to fill the chamber through capillary action.
- Allow the RBCs to Settle:
- Allow the RBCs to settle for a few minutes to ensure an even distribution across the counting area.
- Microscopic Examination:
- Place the loaded Neubauer chamber on the microscope stage. Using the low-power objective (usually 10x), locate the counting grid.
- Counting RBCs:
- Count the RBCs within the specified counting areas (usually the four large corner squares) using the high-power objective (usually 40x).
- Calculations:
- Calculate the RBC count per microliter (µL) using the formula:
- The depth factor for a Neubauer chamber is 0.1, and the volume of one large square is 1 mm².
- Repeat the Process:
- Perform the counting in multiple squares and calculate the average for accuracy.
- Clean the Chamber:
- Clean the Neubauer chamber thoroughly with distilled water and dry it before the next use.
Keynotes on Manual RBCs count
- Precision is crucial, so take your time during counting and ensure the Neubauer chamber is clean.
- Always follow safety protocols when handling blood samples.
- Consult the laboratory’s standard operating procedures (SOPs) for specific guidelines.
- This technique provides an estimate of the RBC count and is a valuable tool in hematology. Always consult with healthcare professionals or laboratory experts for accurate and reliable results.