Abstract: A glucose oxidase reagent used in an instrumental analyzer, wherein glucose concentration is determined as directly proportional to the rate of oxygen comsumption by glucose in a sample of a biological fluid, is regenerated by mixing and collecting the used reagent in a waste bottle containing sufficient catalase to provide a concentration of at least 2 U/ml of catalase in the total amount of waste liquid. A new glucose oxidase reagent formulation is also provided which contains at least 90 U/ml of catalase and can be continuously recycled by passing the used reagent directly back into the fresh reagent without first collecting in a waste bottle.