NAD/NADH and NADP/NADPH are important biological cofactors for oxidoreductase enzymes that are fundamental for various biological processes such as energy metabolism mitochondrial function oxidative stress immunological functions and cell death. Hence the oxidoreductase enzymes are used as indicators of metabolic activity of cells.EZMTT is a novel monosulfonated tetrazolium salt 2-(3-(2-methoxy-4-nitrophenyl)-2-(4-nitrophenyl)-2H-tetrazol-3-ium-5-yl) benzenesulfonate sodium salt (EZMTT). The EZMTT reagents provided high quality and reproducible detection for oxidoreductase enzymes indicators of cellular metabolic activity. Upon reacting with metabolic enzymes EZMTT is converted to a yellowish formazan that does not require a solubilization step and can be measured by absorbance at 450 nm. EZMTT assay can continuously track cell proliferation and measure cytotoxicity (loss of viable cells) or cytostatic activity (shift from proliferation to quiescence) of potential medicinal or t