Abstract Background Uric acid and urea are two parameters widely used in the diagnosis and management of renal pathology. In our laboratory, they are determined using Atellica Solution® analyzers (Siemens Healthineers). After validating a new Siemens equipment, Atellica CI®, it is essential to ensure result interchangeability in our laboratory accredited by ISO 15189:2012. Objectives evaluate the interchangeability of results for uric acid and urea measured by Atellica Solution® and CI® analyzers. Methods A total of 40 serum samples from patients with uric acid values between 1.3 and 15.2 mg/dL, and another 40 serum samples from patients with urea values between 7 and 142 mg/dL were processed in parallel. Statistical analysis of the results was performed using Passing-Bablok regression and Bland Altman mean difference analysis with Method Validator Version 1.19. Results are expressed with their 95% confidence interval. Results Uric Acid: After analyzing Bland-Altman differences, a statistically significant slight systematic error was found, as the 95% CI does not include 0, with slightly higher results in CI 1900®. Regarding Passing-Bablok regression analysis, there were no systematic errors of constant type (since the 95% CI of the intercept includes 0) but a discreet significant proportional systematic error was observed (the confidence interval of the slope does not include 1).Urea: In Bland-Altman analysis, a discreet systematic error was observed as the 95% CI of the mean difference does not include the null value. Regarding Passing-Bablok regression analysis, there were no systematic errors of constant type (since the 95% CI of the intercept includes 0) or proportional type (since the 95% CI of the slope includes 1), indicating interchangeability between both analyzers. Conclusions The results obtained by both Atellica Solution® and CI® analyzers for uric acid and urea assays are interchangeable since the statistically significant differences observed can be considered analytically and clinically insignificant.
Read full abstract