A total direct cell counting is a method commonly used to count the concentration of cells in a solution. The instruments used are a hemocytometer, a specialized slide, called counting chamber and a microscope. It is considered an accurate count since it is widely used. However, a disadvantage of these methods is that there can not be a differentiation between dead and live cells. This means that dead and live bacteria will both be measured and there will not be an accurate estimation of the infectious dose.
