A new, more amenable method for HTS environments combines the protease substrates for viability and cytotoxicity allowing for simultaneous measurement of viable and non-viable cell populations (Fig. 6) . This method delivers broad linear responses (0-50,000 cells/well) and can measure as little as a 2% change in viability in both the AFC and R110 channels [59] . Furthermore, the reagent can be concentrated and delivered into assay wells in a substantially reduced volume to accommodate a third spectrally distinct reagent.