Analytical Evaluation of Vitamin D Measurements in Routine Laboratories

Its increasing clinical importance has turned 25-hydroxy-Vitamin D (25(OH)D) into an indispensable test in clinical laboratories. In this study, we aimed to analyze the analytical performances of two widely used immunoassays, namely new restandardized Abbott product Architect 25-OH Vitamin D test and the Beckman Coulter product Access 25(OH) Vitamin D Total Test by making comparisons with the reference method liquid chromatography tandem mass spectrometry (LC-MS/MS).

The new restandardized Architect I2000SR System (Abbott Laboratories, IL, USA; ref 5P02) and Access2 (Beckman Coulter, Brea, CA, USA; ref B24838) immunoassay were compared with LC-MS/MS (Shimadzu LCMS-8030, Kyoto, Japan) method 25(OH)D test for precision and reproducibility in 90 serum samples. In comparison with reference method, Deming Regression analysis and Bland Altman graphs were used.

Within run coefficient of variation (CV%) for Architect was found to be lower than 3.1%. Within run coefficient of variation (CV%) for Access2 was lower than 7.04%. When compared with LC-MS/MS, R value of Architect 25-OH Vitamin D kit was 0.911 (intercept 1.62, slope 1.06), mean bias was -0.04% and for Access 25(OH) Vitamin D Total kit, R value was 0.841 (intercept 9.43, slope 0.92) and mean bias of 6.9%.

When renewed 5P02 Abbott Architect 25(OH)D and Beckman Coulter Access2 25(OH)D Total tests were compared with LC-MS/MS method in our study, they were found to have appropriate analytical values.