Background: The measurement of serum ferritin (SF) is generally considered to be a reliable indicator of iron status in vivo. The accurate assessment of SF concentration promoted us to evaluate the analytical performance of two automated immunoassays.
Methods: A total of 125 different concentrations of clinical samples were routinely collected and determined by two analytical systems: the Architect i2000 system from Abbott Laboratories and the Cobas E601 from Roche Diagnostics. We evaluated the analytical performance of the two systems and compared the measurements of SF results, which covered the whole analytical range.
Results: The analytical performance and accuracy of the two systems were fairly good, and a satisfactory correlation was achieved between the two methods (r = 0.99), but Bland-Altman analysis suggested that the Cobas E601 was, on average, 60.6 ng/mL higher than the i2000, with wide limits of agreement (95% limits of agreement: -78.3 to 199.5 ng/mL).
Conclusions: These findings suggested that the two methods had good correlation but were not interchangeable. Patients should always be monitored for SF with the same method and it should be indicated in the report.