Orangu™ is a non-cytotoxic, sensitive, colorimetric assay for the determination of cell viability in cell proliferation and cytotoxicity assays. Orangu™ utilizes WST-8 which is metabolized by cells to give an orange-coloured formazan dye. The amount of dye formed is directly proportional to the number of living cells. Increasing incubation periods or number of cells will lead to an increase in the amount of orange dye.