5-Bromo-4-Chloro-3-Indolyl Phosphate/nitroblue Tetrazolium (BCIP/NBT) SolutionIs a widely used chromogen for immunohistochemical and in-situ staining. This reagent is available as a single component, ready-to-use reagent. When in the presence of the Alkaline-Phosphatase enzyme, BCIP/NBT produces a purple precipitate that is soluble in alcohol.