CytoTox 96 Non-Radioactive Cytotoxicity Assay is a colorimetric alternative to radioactive cytotoxicity assays. It quantitatively measures LDH, a stable cytosolic enzyme released upon cell lysis, in much the same way as [51Cr] is released in radioactive assays. Released LDH in culture supernatants is measured with a 30-minute coupled enzymatic assay that results in the conversion of a tetrazolium salt (INT) into a red formazan product.