A Haemocytometer is a widely used device for visually counting the number of cells in a blood sample or other fluid under a microscope. It consists of a thick glass microscope slide with a gridded indentation that creates a H shaped chamber, contact of a flat cover slip on top produces an exact volume of fluid over the counting area. By counting the number of cells or particulates in one particular section of the gird you can then calculate the concentration of cells in the fluid overall. Having a metallized coating to your chamber can help you reach the highest levels of accuracy.
A counting chamber with a rhodium coated (metallized) central platform, such as the Improved Neubauer by Hawksley, has multiple advantages. Unlike a normal chamber which lines are ruled directly on the glass, the lines of a rhodium coated chamber are ruled through a semi-transparent film of metal.
These lines show up bright against a darker, neutral background, and this grid can be viewed as either light or dark by shifting the contrast. This makes it easier to identify the boundary lines and thus estimate the numbers of cells more clearly. Filling is easier, the blood cells being evenly distributed and clearly defined against a darker background. Microscope adjustments are also less critical in getting an accurate result due to the contrast provided by the metal coating. The metallized area needs no special care beyond that given to an ordinary counting chamber.
As well as having a metallized chamber the Hawksley counting chambers comply to the BS 788 standard which meet the very high demands of scientific accuracy. The cell depth over ruled areas are accurate up to ± 0.001mm, the cover glass support platforms are ground and polished optically flat and co-planar with ruled area to ± 0.001mm. The gap between the cover glass and platform will not vary from the stated depth by more than ± 0.001mm. These standards ensure they conform to the highest standard of dimensional accuracy to keep the counting chambers strictly reliable.