Lack of transferability between different immunoassays and LC-MS/MS for total 25-hydroxyvitamin D measurement and disagreement defining deficiency.

Background: Over the last few years, it has become much more common to measure concentrations of vitamin D, as its deficiency has been associated with an increasing number of health problems. Recently, a number of new immunoassays for measurement of total 25-hydroxyvitamin D (25OH-D) concentration have been released but their results may not be transferable.

Methods: Our main objective was to compare results from the Cobas(®) e411 (Roche Diagnostics), Advia Centaur(®) (Siemens), Architect (Abbott), IDS-iSYS (Vitro S.