Cytotoxicity assays are used to predict acute toxicity of drugs and other chemicals to cells and tissues. Cytotoxicity assays can be used with various cell lines, e.g. neural cells, fibroblasts, epithelial cells etc. Cytotoxicity tests have also an essential role in the development of more complex methods (described above) as an endpoint or as a pre-test to ensure that only sub-toxic concentrations are used in the methods.  

Different cytotoxicity tests measure chemical effects on different cellular structures and functions. FICAM is using e.g. following cytotoxicity tests:

• Total cellular ATP-measurement (by bioluminescence). ATP is the prime source of energy in the cells and relates to cellular health and physiological state. Hence, total cellular ATP-measurement indicates chemical effects on general cellular metabolism and viability.
• LIVE/DEAD® Viability/Cytotoxicity assay.  LIVE/DEAD® Viability/Cytotoxicity assay is a two-color fluorescence assay that measures two parameters of cell viability.  Membrane-permeant calcein AM is cleaved by esterases in live cells to yield cytoplasmic green fluorescence, and membrane-impermeant ethidium homodimer-1 labels nucleic acids of membrane-compromised cells with red fluorescence.  Hence LIVE/DEAD® Viability/Cytotoxicity assay indicates chemical effects on membrane integrity and metabolism. The assay differentiates between dead and living cells.
• Neutral red uptake. NRU assay is a colorimetric assay based on the ability of lysosomes of living cells to take up and store neutral red dye. Hence, NRU assay indicates chemical effects on lysosomal activity and membrane permeability.
• WST-1 test. WST-1 is a colorimetric assay that bases on reduction of WST-1 by mitochondrial succinate dehydrogenase to a coloured formazan product. Hence, WST-1 assay indicates chemical effects on mitochondrial metabolism and respiratory toxicity.