Fast Red is a widely used chromogen for immunohistochemical staining. Warp Red is an advanced formulation of Fast Red that accelerates and intensifies staining. When in the presence of alkaline phosphatase (AP) enzyme, Warp Red produces a bright fuchsin-red precipitate that is insoluble in organic solvents and can be coverslipped with a permanent mounting media. Typically, Warp Red achieves staining intensity in 5-7 minutes that is equivalent to the staining previously observed with Vulcan Fast Red in 15-20 minutes. If users desire even more intense staining, Warp Red can be extended to 10 minutes. Warp Red is compatible with most alkaline phosphatase detection systems, including, MACH 2, MACH 3, MACH 4, 4plus, and Promark. Warp Red may also be used in multiplex detection systems, such as MACH 2 Double Stain, for Multiplex IHC applications.