Comparison of routine test kits of creatinine in human serum with reversed-phase high-pressure liquid chromatographic assay

Objective Precision and accuracy of Creatinine determination by Reversed-Phase High-Pressure Liquid Chromatographic Assay (HPLC) was investigated.This method was used as the criterion to evaluate the accuracy of routine test kits.Methods Beckman LX20 measure system used kinetic Jaffe method.Vitros250 Chemistry System used Vitro dry chemistry test kits,and enzymatic method was on the Hitachi 7170 Automated Analyzer.As to HPLC,C18 was stationary phase,and 5-Fluorouracil (5-Fu) was internal standard.Creatinine was determined at 235 nm.Results The with-in-day CVs (n=5) and day-to-day CVs(n=20)of HPLC were 2.0% and 5.1%,respectively.The absolute recovery was 95.31%,and the relative recovery was 98.95%.The results of certified reference materials were consistent with the target value,and average deviation was -0.31%～1.35%.HPLC was served as the independent variable.When ereatinine was 200 μmol/L,Bias of Beckman LX20 system,Vitros dry chemistry system and enzymatic method were -19%～21%,-14%～21% and -30%～11%, respectively;when creatinine was 200 μmol/L,Bias of Beckman LX20 system,Vitros dry chemistry system and enzymatic method were -10%～13%,-13%～14% and -20%～10%,respectively.Bias of enzymatic method results was mostly negative,when creatinine was 70 μmol/L,some could be -30%. Conclusions The precision and accuracy of HPLC was perfect.Compared with HPLC,bias of Beckman LX20 and Vitros system were relatively little,but enzymatic method results were lower than HPLC,Beckman LX20 system and Vitros system,and when creatinine concentration 70 μmol/L,enzymatic method could not measure exactly.