LAUSR

Objectives We evaluated performance and measurement uncertainty of the newly released ARCHITECT 25-OH vitamin D 5P02 assay (Abbott Diagnostics, Abbott Park, IL). Methods In total, 300 samples were used to compare the results from ELECSYS Vitamin D Total (Roche Diagnostics, Mannheim, Germany) and ADVIA Centaur Vitamin D Total (Siemens, Tarrytown, NY). To quantify the measurement uncertainty, 25 samples and four levels of standard reference material (SRM) were measured using isotope dilution-liquid chromatography-tandem mass spectrometry according to international guidelines. Results The results of the ARCHITECT assay were equivalent to other immunoassays, but correlation coefficients were lower than the recommended criterion. SRM level 2 was considered adequate for uncertainty estimation, and the expanded measurement uncertainty of the ARCHITECT assay was 4.2%, which was superior to the other two assays. Conclusions The restandardized ARCHITECT assay has acceptable performance in a clinical setting. However, there is still a need for further standardization of total vitamin D measurement among the automated immunoassays.