Serum Creatinine Kit measures creatinine in serum and plasma samples. A creatinine standard, calibrated to a NIST creatinine standard, is provided to generate a standard curve. The color generating reaction is initiated with the Creatinine Detection Reagent. The assay utilizes a kinetic absorbance method to overcome interference by colored compounds in the sample. The concentration of creatinine is calculated using the delta of the optical density readings at 1 and 30 minutes. We offer a free Excel worksheet for concentration calculations.