Naphthol AS-BI phosphate disodium salt hydrate is widely used in biochemical and histochemical applications as a substrate for enzyme detection. It is particularly valuable in the identification of alkaline phosphatase activity in tissues and cells. When the enzyme alkaline phosphatase is present, it hydrolyzes the compound, releasing a colored product that can be visualized under a microscope. This makes it a critical tool in diagnostic laboratories for studying enzyme distribution and activity in biological samples. Additionally, it is employed in research settings to investigate cellular processes and disease mechanisms, providing insights into enzyme-related pathologies. Its stability and specificity make it a reliable choice for staining and detection techniques in both clinical and experimental contexts.