Patent ID: 6210971
Filing Date: 2001-04-03
Classification: G01N,Y10S,Y10T

Abstract:
In the method for the determination of creatinine in a fluid test sample which involves contacting the fluid test sample with a reagent composition comprising cupric ions, a hydroperoxide, citrate and an oxidizable dye which provides a colored response in the presence of oxygen free radicals and a pseudoperoxide and determining the concentration of creatinine in the fluid test sample by determining the intensity of the colored response and comparing this intensity to that obtained using fluid test samples containing known concentrations of creatinine; the improvement which comprises introducing a stabilizing amount of an ionizable phosphate containing compound having the formula: ##STR4##wherein 2, 3, 4 and 5 are selected from the group consisting of ##STR5##1 is any of the above or --O--, M is H or a group I or II metal,and m and n are independently O or 1, to the reagent composition to stabilize the reagent composition before contacting it with the fluid test sample by preventing the oxidation of the dye in the absence of the fluid test sample.