Creatinine (2-amino-1-methyl-2-imidazolidin-4-ketone) is a metabolite formed from creatine and phosphocreatine. Creatine and phosphocreatine are converted to creatinine in a non-enzymatic manner, and creatinine enters the bloodstream and is filtered by the glomerulus and excreted by the kidneys. Creatinine is found mainly in muscles, heart, brain and photoreceptor cells of retina. 

3.    Prevent the formulation of bubbles when the supernatant is transferred into the microplate.

1.  Preparation of standard: Dilute 1 mmol/L Standard solution with double-distilled water to a serial concentration. The recommended dilution gradient is as follows: 0.8, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0 mmol/L.

    Standard wells: Add 10 μL of standard solution with different concentrations into the wells.

    Sample wells: Add 10 μL of Sample into the wells.

2.  Add 150 μL of Reagent 1 to each well and incubate at 37℃ for 5 min.

3.  Add 50 μL of Reagent 2 to each well, incubate at 37℃ for 2 min and measure the OD value (A1) of each well at 515 nm.

4.  Incubate at 37℃ for 3 min and measure the OD value (A2) of each well at 515 nm.