Objective To evaluate the consistency of estradiol kits between E2-Ⅲ and the upgraded Enhanced Estradiol(eE2)kit with chemiluminescence immunoassay analyzer Siemens ADVIA Centaur.Methods Used duplicate samples and removed outliers to test the two reagents′stability;document EP9-A2 were used as reference to do the methodological comparison and bias estimation. Results There was good correlation between the two reagents with different concentrations,the correlation coefficients were grea-ter than 0.975;the percentage of bias was varied among different groups.Conclusion It is effective to reduce the interference of up-dated estradiol kits on the assisted reproduction treatment cycles by assessing the bias through comparison tests of the two kits in advance.