Among the well-known viable cell count methods developed so
far, manual counting with a hemocytometer has been the most
commonly used method due to its low cost and versatility [4]. This
method depends on the analyst’s ability to evaluate different cell
attributes regardless of the cell type; in addition allows using
different staining techniques according to the purpose of the
analyses (Table 1). However, the procedure is time consuming,
which precludes the analysis of a large amount of samples at one
time and is subject to inter-user variation depending on the degree
of expertise of the analyst