Red Cell Count by Haemocytometer

Haemocytometer is an instrument used to measure the concentration of cells or particles in a liquid sample. Red cell count is carried out using this instrument by following the below steps:

1. Preparation of Diluted Blood Sample: A small amount of blood is collected and mixed with a diluting fluid such as Hayem's fluid or isotonic saline to reduce the concentration of cells in the sample. This is done to ensure that the cells are evenly distributed on the counting area of the haemocytometer.

2. Loading the Haemocytometer: The haemocytometer has two chambers, each with a counting area marked by a grid. A small volume of the diluted blood sample is loaded onto the counting area of the haemocytometer using a pipette.

3. Counting the Red Blood Cells: The red blood cells are counted using a microscope under high magnification. The cells in each of the squares on the grid are counted and the average is calculated. The total number of cells is then calculated by multiplying the average count by the number of squares on the grid.

4. Calculation of Red Cell Count: The red cell count is calculated by dividing the total number of cells by the volume of the diluted blood sample.

The red cell count is an important diagnostic test used to evaluate a patient's blood count and to diagnose conditions such as anaemia, polycythaemia, and haemolytic disease. The haemocytometer is a reliable and accurate instrument for counting red blood cells and is widely used in clinical laboratories.