Stable NBT solution useful in blotting assays for measuring dehydrogenases and in oxidase histochemistry for measuring oxygen and analyte detection systems that employ dehydrogenase enzyme chemistry. NBT has been employed extensively in dehydrogenase and oxidase chemistry. In the case of dehydrogenases, NAD or NADP along with intermediary electron acceptors/donors such as phenazine methosulfate, Meldola