In vitro reagent for the quantitative determination of creatinine in human serum, plasma, and urine on cobas c systems using the compensated Jaffé (kinetic colorimetric) method. Creatinine measurements are used in the diagnosis and monitoring of renal function and as a component of the estimated glomerular filtration rate (eGFR). Compatible with COBAS INTEGRA 400 plus, cobas c 311, c 501, c 502, c 701, c 702 analysers.