The VisionBlue™ Quick Cell Proliferation Assay Kit provides by far the most sensitive and easiest means for quantifying cell proliferation and viability. Simply add the single reagent to cell culture, incubate and read the fluorescence intensity. The VisionBlue™assay utilizes the redox dye resazurin which is not fluorescent, but upon reduction by viable metabolically active cells, the dye becomes highly fluorescent (Ex = 530-570 nm; Em = 590-620 nm). Therefore, viable metabolically active cells can be easily measured.