Objective To develop improved enzymatic creatinine(Cr)assay reagents (self-R&D),and to investigate their appli-cation on serum detection by comparing with imported commercial Cr reagents(enzymatic Cr reagents from Toyobo)Methods En-zymatic method was used to evaluate the effect of every component and different concentrations of reagents on Cr assay by detecting the alteration of absorbance of Cr before or after the reaction.Meanwhile,the blank absorbance and analysis sensitivity of self-R&D and imported reagents,the technical indicators of precision,linearity,as well as method comparison of self-R&D reagents,were de-tected on the same automatic biochemical analyzer.Results The blank absorbance of self-R&D reagents was 0.009,and the detec-tion sensitivity was 0.13,better than that of imported Cr reagents.The coefficient of variation (CV)of high and low values of ser-um of self-R&D reagents were 1.5%,and 1.1%,respectively.The linear range was 0-2 850 μmol/L and the method comparison result was Y =0.98X +1.15 (r =0.999).The expected bias was less than the allowable error region.Using relative deviation≥10% as an index to evaluate the existence of significant interference,it shows that 35 mmol/L of creatine,3.42 mmol/L of biliru-bin,0.03 g/L of vitamin C,5 g/L of hemoglobin and 1450 FTU chyle in both low and high concentration serum samples did not interfere with the test result.Conclusion The quality of self-R&D reagents was good,and there was a good relativity between self-R&D reagents and imported Cr reagents with excellent quality.This indicates the self-R&D reagents could satisfy the application requirements of the clinics.