Measurement of circulating 25-hydroxyvitamin D: A historical review

Abstract

The constantly increasing requests for the measurement of serum 25-hydroxyvitamin D over the last years has led reagent manufacturers to market different automated and semi-automated methods, that being unfortunately not fully harmonized, yield different results. Liquid chromatography coupled to tandem mass spectrometry (LC/MS2) has more recently been introduced. This approach allows the distinction between the two forms of 25-hydroxyvitamin D and to measure other metabolites. This approach also requires harmonization to curtail the differences between the different analytical methods. To meet this requirement, the American National Institutes of Health (NIH), the Centre for Disease Control and Prevention (CDC) in Atlanta, the National Institute of Standards and Technology (NIST) and the vitamin D Reference laboratory of Ghent University have pooled their expertise to develop a standardization program.This article reviews the main elements and the difficulties of the automated and semi-automated methods for 25-hydroxyvitamin D, from sample preparation to the analytical phase, as well as those related to mass spectrometry. It also emphasizes the need for standardization to better define the clinical decision thresholds of vitamin D nutritional status.

The vitamin D metabolome: An update on analysis and function

“…Automated enzyme linked immunoassays were then established and marketed. Whilst most of these methods demonstrated selectivity between 25OHD3 and 25OHD2, some assays were found to underestimate 25OHD2 by up to 25% . The first high performance liquid chromatography method was published in 1977 using UV absorbance for the analysis of 25OHD2 and 25OHD3 .…”

“…Whilst most of these methods demonstrated selectivity between 25OHD3 and 25OHD2, some assays were found to underestimate 25OHD2 by up to 25% . The first high performance liquid chromatography method was published in 1977 using UV absorbance for the analysis of 25OHD2 and 25OHD3 . One of the first mass spectrometry methods for vitamin D analysis was described in 1991 with the ability to quantify multiple vitamin D metabolites, including vitamin D2 and D3, 25OHD3, 1,25(OH) 2 D3, and 24,25(OH) 2 D3 .…”

“…The RIA was as sensitive as competitive protein binding assays; however, cross reactivity occurred with 25OHD2 and 1α,25(OH) 2 D3. 163,164 Automated enzyme linked immunoassays were then established and marketed. Whilst most of these methods demonstrated selectivity between 25OHD3 and 25OHD2, some assays were found to underestimate 25OHD2 by up to 25%.…”

“…163 The first high performance liquid chromatography method was published in 1977 using UV absorbance for the analysis of 25OHD2 and 25OHD3. 163,165 One of the first mass spectrometry methods for vitamin D analysis was described in 1991 with the ability to quantify multiple vitamin D metabolites, including vitamin D2 and D3, 25OHD3, 1,25(OH) 2 D3, and 24,25(OH) 2 D3. 163,166 The use of mass spectrometry, in particular, LC-MS/MS methods for vitamin D analysis has continued to grow with methods that are selective for differentiating between 25OHD2 and 25OHD3 along with avoiding cross reactivity through separating isobar interference.…”

“…163,165 One of the first mass spectrometry methods for vitamin D analysis was described in 1991 with the ability to quantify multiple vitamin D metabolites, including vitamin D2 and D3, 25OHD3, 1,25(OH) 2 D3, and 24,25(OH) 2 D3. 163,166 The use of mass spectrometry, in particular, LC-MS/MS methods for vitamin D analysis has continued to grow with methods that are selective for differentiating between 25OHD2 and 25OHD3 along with avoiding cross reactivity through separating isobar interference. 167,168 The first assays for measuring circulating 1,25(OH) 2 D were performed using competitive protein binding assay using chicken intestinal vitamin D receptor.…”