Estimation of Cell Number by Hemocytometry Counting

The number of mammalian cells in a defined volume of medium can be measured using a hemocytometer. Automated methods using cell-counting devices such as those produced by Coulter are desirable when large numbers of individual samples are to be counted. A hemocytometer contains two chambers, each of which when filled and coverslipped contains a total volume of 9 µL. Each chamber is ruled into nine major squares, and each square is 1 × 1 mm with a depth of 0.1 mm. Thus, when coverslipped, the volume of each square is 0.1 mm³ or 0.1 µL. Additional subdivisions of the major nine squares are not necessary for counting and can be ignored.