FLIVO? kits provide a simple and accurate method to detect caspase activity in vivo. The NIR-FLIVO Free Dye Control Assay contains the NIR fluorescent dye molecule (without the caspase-targeting moiety) and are designed to be used in coordination with the NIR-FLIVO 747 Tracer Assay to determine background fluorescence signal. Both the Free Dye Control and the Tracer reagents will gen-erate a fluorescent signal when injected into animals, but only the Tracer should bind to active caspases and remain inside an apoptotic cell. The fluorescent signal generated from the Free Dye Control reveals where the fluorescent reagent may have become trapped inside the cell, tissues, or body of the animal without specifically binding with an active caspase. In the context of the overall experiment, this base level of fluores-cence is considered background noise compared with the signal generated in animals that were injected with the NIR-FLIVO Tracer.
