A class of compounds of monosulfonic phenyltetrazole, with the structure of 2-(R1 phenyl)-5 (2-sulfonic phenyl)-2H-tetrazole. The 2-sulfonic phenyl tetrazolium salt of this invention has advantages of low toxicity, short synthetic route, easy control of purity and quality. As the 2-sulfonic phenyl tetrazolium salts has almost no absorption at 450 nm where the reduzate has greater absorption, spectrophotometry can simply and rapidly determine the activity of glutamate dehydrogenase, or the content of NADH/NADPH.

Clostridium difficile disease involves a range of clinical presentations ranging from carrier status with other causes of symptoms to mild and self-limiting diarrhea to life-threatening pseudomembranous colitis and megacolon. Cases of C. difficile are treated differently depending on the presence and then the severity of disease. Patients that are carriers may not receive treatment with concern of causing the disease. Mild to moderate cases may be treated with metronidazole while severe and relapsing cases are often treated with vancomycin or fidaxomicin. Current molecular assays are highly sensitive for detecting toxigenic C. difficile and cannot rule out carrier status. Utilization of a biomarker panel that includes C. difficile antigen (GDH), toxins A and B, and fecal lactoferrin allows clinicians to differentiate between a carrier state and active state of C. difficile and allows for monitoring to evaluate the effectiveness of treatment.

A class of compounds of monosulfonic phenyltetrazole, with the structure of 2-(R1 phenyl)-5 (2-sulfonic phenyl)-2H-tetrazole. The 2-sulfonic phenyl tetrazolium salt of this invention has advantages of low toxicity, short synthetic route, easy control of purity and quality. As the 2-sulfonic phenyl tetrazolium salts has almost no absorption at 450 nm where the reduzate has greater absorption, spectrophotometry can simply and rapidly determine the activity of glutamate dehydrogenase, or the content of NADH/NADPH.