Biotinyl tyramide is a substrate of the horseradish peroxidase enzyme. Used as a reagent to amplify immunohistochemical signals. Fluorescence-based tyramide signal amplification (TSA) has been widely used in immunohistochemistry, immunoelectron microscopy, fluorescent in situ hybridization (FISH) and fluorescence ELISA. The TSA method has been reported to increase the detection sensitivity up to 100-fold as compared with conventional avidin-biotinylated enzyme complex procedures. It can be added to any standard IHC protocol and reduces the use of other reagents; it improves signal to noise by reducing the titer of other reagents in the assay protocol; it enables multi-target detection in both IHC and (F)ISH applications.