What Is a Counting Chamber?

 

A counting chamber, also known as a haemocytometer, is a laboratory tool that scientists use to count cells under a microscope. Researchers first designed it to count blood cells. However, laboratories now use it to measure many types of cells, including sperm cells, bacteria, yeast and cultured cells.

Manufacturers produce the chamber from thick optical glass and engrave a fine grid onto its surface. Each square on the grid has precise dimensions. As a result, users can calculate the number of cells in a liquid sample because they know both the grid area and the chamber depth.

How a Counting Chamber Works

The chamber creates a small and controlled space for analysis. First, the user places a specially designed coverslip on top of the chamber. This coverslip has a standard thickness and forms a narrow gap above the grid.

Next, the user places a small drop of liquid at the edge of the coverslip. Capillary action then draws the sample into the chamber and spreads it evenly across the grid.

Because the gap has a fixed depth, the liquid remains at a constant height. Therefore, once the user counts the cells within selected squares, they can calculate the number of cells per millilitre.

Preparing the Chamber

Before loading the sample, the user lightly moistens the outer supports with distilled water. This step helps the coverslip settle correctly.

The user then applies gentle pressure to secure the coverslip in place. When it sits properly, faint circular patterns known as Newton rings appear. These rings indicate good contact between the glass surfaces. Since the coverslip can break easily, careful handling remains important throughout the process.

Loading the Sample

Accurate results depend on proper preparation. For this reason, the user mixes the sample thoroughly before use. After drawing the liquid into a pipette, they discard the first drop to improve consistency.

Then, they wipe the outside of the pipette and tilt it slightly to form a small droplet. At this point, they place the droplet at the edge of the coverslip.

Capillary action pulls the liquid into the chamber. To maintain accuracy, the user removes the pipette before the liquid reaches the outer edges. This prevents overfilling and keeps the volume consistent.

Counting the Cells

Clear rules guide the counting process. Cells that lie fully inside a square are included in the total. In addition, cells that touch the top or left boundary lines are counted. However, cells touching the bottom or right lines are excluded to avoid double counting.

To stay organised, the user moves across the grid in a steady back-and-forth pattern. Consequently, this method reduces errors and improves consistency.

Where Counting Chambers Are Used

Although automated systems now handle most routine blood analysis, many laboratories still rely on counting chambers for specific tasks. For example, fertility laboratories measure sperm concentration and observe movement with them. Similarly, microbiology laboratories count bacteria and fungal spores. Universities also use them to teach practical laboratory skills. In addition, breweries measure yeast levels during production. A counting chamber offers a straightforward and controlled way to count and examine cells. Because its grid and depth remain fixed, users can calculate cell concentration with confidence. get your today. visit www.cryolab.co.uk