Calcein Violet-AM is a fluorogenic, cell-permeant fluorescent probe that indicates cellular health by detecting the activity of nonspecific esterases. When the acetoxymethyl ester is intact the probe is non-fluorescent, but when it is cleaved by nonspecific esterases present in healthy cells, the probe can be excited and emit at 400nm/452nm respectively. The signal of Calcein Violet-AM is proportional to the cell vitality, as esterase activity decreases in cells with poor vitality. This cell-permeant probe is not retained with fixation and permeabilization.