It was originally intended to count the number of red blood cells in a sample of blood, hence the name hemocytometer (also known as a hemocytometer, haemocytometer, or haemocytometer) and other variations. A method for counting all types of cells, including unicellular organisms such as bacteria, yeast, and protozoa as well as dispersed cells from multicellular organisms, among other things, quickly gained widespread acceptance. Hemocytometers are devices that measure hemoglobin concentration by using two Neubauer chambers on a single slide, each with an etched grid and a known volume. With a hemocytometer, manual cell counting is accomplished by first attaching the hemocytometer's cover slip to the instrument, after which a cell suspension is drawn into a chamber by capillary action. Each cell in a specific area of the grid is counted individually under the microscope in order to determine the total number of cells. For the purpose of calculating cell concentration, it is necessary to know the volume of the grid area that has been selected. The low cost and ease of use of a traditional hemocytometer are both appealing characteristics; however, manual cell counting with a hemocytometer has a number of drawbacks that must be considered. It is impossible to obtain accurate counts using a hemocytometer when dealing with dilute cell suspensions. When using a hemocytometer, the lower limit for accurate cell counting is generally agreed upon to be 2.5 x 105 cells per milliliter of blood in most cases. By counting multiple aliquots at the lower limit of the sample volume, the accuracy of a sample can be improved; however, this is time-consuming and can present a problem with small sample volumes.
Furthermore, a high concentration of cells can result in inaccurate cell number determinations if the concentration is too high
When there are a large number of cells within the area that is being counted, errors in counting are more likely to occur as a result of miscounted cells and cells becoming disoriented within the grid, as well as when there is a large number of cells within the area that is being counted
It is generally recommended that samples containing cell counts greater than 2
5 x 106/ml be diluted before testing in order to avoid contamination
Another potential problem to be concerned about is the introduction of an excessively large or insufficiently small volume into the chamber of the hemocytometer. A common error is to introduce a volume that is too large, which results in the cover slip being slightly lifted. The cell counts are overestimated as a result of the increased volume as a result of this. In contrast to cell counters, hemocytometers are more affordable initially, which appeals to many budget-conscious experimentalists. However, it is important to consider the long-term costs of additional labor as well as the ultimate cost of inaccurate results over a hemocytometer's useful life span before making a purchase decision. Additionally, cell counters enable cell biology researchers to conduct experiments using previously unattainable methods, in addition to the time and labor savings and increased accuracy that cell counters provide. An advanced automated , such as Bio-Rad's TC20TM cell counter, provides greater flexibility than a hemocytometer in that it allows users to specify the size of the cells to be counted. This feature allows you to selectively count cells within a specified size range by specifying the size range. Consequently, it is now possible to count subpopulations within mixed populations that have a variety of cell sizes as a result of this improvement. This is an extremely useful capability when it comes to protocols that involve coculture as well as primary cells isolated from tissue or organs. The ability to gate automated cell counters based on their size significantly increases the usefulness of these counters in many situations. The TC20 cell counter employs autofocusing microscopy on multiple focal planes in order to more accurately calculate the total number of cells. This allows it to determine the best focal plane and exclude debris during the counting process. The use of autofocusing rather than subjective manual focusing is especially important when assessing cell viability because a focal plane that is incorrectly selected will result in inaccurate results. The conventional method of analyzing viability, which employs a single focal plane, can lead to inaccurate conclusions being reached. As a result of light scattering and the alignment of cells with differing heights in a counting chamber, live cells may appear to be dead and vice versa. As a result, dead cells may appear to be alive, and the appearance of live cells may appear to be dead and vice versa. To determine whether or not a cell is viable, the TC20 automated cell counter analyses each cell using images acquired from multiple focal planes during the focusing step, which is performed during the focusing step. In comparison to a hemocytometer, an automated cell counter can provide more accurate cell counts over a wider concentration range. Cell concentrations as low as 5 x 104 cells per milliliter and as high as 1 x 107 cells per milliliter can be accurately counted using this technique. To compare, there is no requirement for many replicate counts at low cell concentrations, and dilution of samples at high cell concentrations is no longer required, as it is with hemocytometry.
Counting BHK Cells using a Countess II FL Automated Cell Counterchinacaremedical.com