Description_x000D_ General description_x000D_ XTT (sodium 3′-[1-[(phenylamino)-carbony]-3,4-tetrazolium]-bis(4-methoxy-6-nitro)benzene-sulfonic acid hydrate) is a tetrazolium salt, which forms water-soluble formazan on bioreduction._x000D_ Application_x000D_ XTT sodium salt has been used to assess cell viability._x000D_ XTT has been used in conjunction with phenazine methosulfate (PMS) to screen human cancer cell lines. The tetrazolium dye has also been used to study fungal cell damage, in testing antimicrobial susceptibility of staphylococci, and in Candida biofilm research. Limitations to the XTT assay have been reported._x000D_ Packaging_x000D_ 100, 500 mg in poly bottle_x000D_ Biochem/physiol Actions_x000D_ XTT (sodium 3′-[1-[(phenylamino)-carbony]-3,4-tetrazolium]-bis(4-methoxy-6-nitro)benzene-sulfonic acid hydrate) is acted upon by dehydrogenases present in metabolically active cells. This produces water soluble formazan, which is a highly colored product. Thus, it offers an advantage in colorimetric proliferation assays, as opposed to MTT, as the product is already soluble and no formazan crystals are formed._x000D_ Principle_x000D_ In living cells, XTT is metabolically reduced to produce a colorimetric, water-soluble formazan product.