test compound toxicology in medicine and in environmental risk assessments , cytotoxicity and antimicrobial susceptibility testing . It has also been used to assess various bacteria, yeast and fungal species and different cell types including, but not limited to fibroblasts , immortalized and cancer cell lines , mouse and human lymphocytes , primary neuronal cell culture , and various animal cell lines . As with any viability assay, optimization and assessment of compatibility must be carried out for every cell model. The objective of this review is to highlight the more important considerations involved in assay use, design and the potential pitfalls. This review gives an introduction and discussion of cell assays including their formats, chemistries, advantages and limitations, followed by a discussion of the Alamar Blue assay which covers basic chemistry, optimization parameters for the user, specific studies in relation to Alamar Blue assay optimization and comparison with other bioassays, concluding statements and a checklist of important points to consider with respect to suitability of the assay to a any given study.