This procedure is based on an improved enzymatic method originally designed to assess serum and urinary creatinine. The assay is performed in two stages. In the first stage, creatine is eliminated during the initial minutes of sample pre-incubation with creatinase. In the second stage, the addition of creatininase initiates the reaction, hydrolyzing creatinine in the sample in the presence of sarcosine oxidase (Sar OD) with the production of hydrogen peroxide:_x000D_
Creatinine + H2O → Creatine_x000D_
Sarcosine + H2O + O2 → H2O2 + Glycine + HCHO_x000D_
The hydrogen peroxide derived from the oxidase reaction is quantified by a Trinder-type reaction in which the chromogenic derivative HTIB and 4-aminoantipyrine (4-AA) condense in the presence of peroxidase (POD) to form a red quinonimine dye._x000D_
4-AA + HTIB → Quinonimine + H2O_x000D_
The color development rate is proportional to the creatinine concentration in the sample.
Creatinine + H2O → Creatine_x000D_
Sarcosine + H2O + O2 → H2O2 + Glycine + HCHO_x000D_
The hydrogen peroxide derived from the oxidase reaction is quantified by a Trinder-type reaction in which the chromogenic derivative HTIB and 4-aminoantipyrine (4-AA) condense in the presence of peroxidase (POD) to form a red quinonimine dye._x000D_
4-AA + HTIB → Quinonimine + H2O_x000D_
The color development rate is proportional to the creatinine concentration in the sample.
