Nitrotetrazolium blue chloride

Colorless to yellow dye that is reducible to blue or black formazan crystals by certain cells; Absorption: NBT has its maximum absorption at 260 nm [in water], and the final product formazan has its maximum absorption at 605 nm [in nitrobenzole]. Nitrotetrazolium Blue (NBT) is used in combination with 5-bromo-4-chloro-3-indoxyl phosphate (BCIP) to detect alkaline phosphatase activity in blotting techniques and in situ hybridization chemistry. BCIP acts as the substrate for alkaline phosphatase, and the oxidizing reagent NBT enhances the purple-brown final color of the precipitates at the reaction sites.

NBT has also been used with X-Gal,or Salmon-Gal to speed up and enhance colony screening.

NBT Reduction Test: Assessment of reduction of NBT dye by stimulated and unstimulated neutrophils to distinguish between nonbacterial and bacterial diseases, the latter causing neutrophils to reduce the dye; used to confirm diagnosis of chronic granulomatous disease.

Synonyms:                                                       2,2′-bis(4-Nitrophenyl)-5,5′-diphenyl-3,3′-(3,3′-dimethoxy-4,4′-diphenylene)ditetrazolium chloride, 3,3′-(3,3′-Dimethoxy-4,4′-biphenylene)bis[2-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride], p-Nitro-Blue tetrazolium chloride, p-Nitrotetrazolium blue, NBT, Nitro BT, 4-Nitrotetrazolium Blue chloride.