Objective:To examine the feasibility and the linear range for serum uric acid assay by integrating a kinetic uricase method with the equilibrium uricase method.Methods:Uricase reaction curves were monitored within 5.0 min by absorbance at 293 nm in 1.2 ml borate buffer(0.20 mol/L

pH 9.2) at 25℃;the absorbance at 293 nm of a reaction solution minus 5 μl uricase solution was measured as the initial absorbance

the absorbance after the addition of 5 μl solution of recombinant Bacillus fastidiosus uricase to complete the reaction was measured as the background absorbance.The difference between the initial absorbance and the background absorbance should be proportional to final levels of uric acid.By the kinetic uricase method

the background absorbance was predicted by kinetic analysis of uricase reaction curve rather than being determined by experimentation.The threshold of a uric acid level for changing from the equilibrium uricase method to the kinetic uricase method was estimated by simulation analysis.The threshold and the linear range of the integration strategy were examined by experimentation.Results:The threshold was 5.0 μmol/L uric acid in reaction solutions by simulation at 40 U/L uricase

and was supported by experimentation.The equilibrium uricase method determined 1.0 to 6.0 μmol/L uric acid.The integration strategy determined uric acid from 1.5 to 60 μmol/L with resistance to final 30 μmol/L xanthine;CV was below 10% for uric acid below 5.0 μmol/L and was lower than 5% for uric acid over 5.0 μmol/L.Conclusion:The integration strategy for uric acid assay had wider linear range

lower cost and practical analysis efficiency.