AbstractBackgroundSerum estradiol (E2) levels may be used in the diagnostic and/or monitoring of a broad variety of clinical conditions. The aims of this study were to evaluate the Siemens enhanced estradiol assay (eE2) on Atellica IM 1600 (Siemens Healthineers) and to perform a sample comparison with the Siemens ADVIA Centaur XP (Siemens Healthineers).MethodsWithin-day and between-day coefficient of variation (CV) were determined using serum sample pools and quality control materials. Six serum samples with decreasing concentrations of E2 were used to assess the limit of quantification. Linearity was evaluated using two different serum samples. Accuracy was evaluated by measuring three certified reference materials. Passing–Bablok regression and Bland–Altman plot were used for comparing Atellica and Centaur XP in 119 serum samples ranging from 45 to 10,059 pmol/L.ResultsWithin-day and between-day imprecision was <6.6%. Accuracy was <6.0% for all values except for 114 pmol/L (22%). The study of limit of quantification resulted in an interday imprecision <20%. High correlation between measured and expected estradiol dilution results was observed (R= 0.99), with recoveries ranging from 77 to 93%. Comparison study showed good agreement and no significant bias.ConclusionsThe study shows that Atellica eE2 assay presents acceptable imprecision and accuracy and correlates well with Centaur XP.