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Abstract Introduction
Evidence of the skeletal and nonskeletal effects of vitamin D, coupled with recognition that vitamin D deficiency is common, has raised interest in what is called a vitamin but is in fact a hormone. Vitamin D is produced by the action of ultraviolet B radiation on skin or obtained from dietary sources, including supplements. Persons commonly at risk for vitamin D deficiency include those with inadequate sun exposure, limited oral intake, or impaired intestinal absorption. Vitamin D sufficiency is best determined by measurement of 25-Hydroxy Vitamin D in serum, which allows precise evaluation of Vitamin D sufficiency as well as monitoring of vitamin D supplementation. In measuring 25-Hydroxy Vitamin D it is desirable that the C3 epimers should be separated, as significant epimer concentrations have been observed not only in newborns but also in adults and have a biological activity apparently different from vitamin D itself.
Material and Methods
This presentation details analytical data of the updated Vitamin D assay designed for the fully automated Thermo Scientific™ Cascadion™ SM Clinical Analyzer*. This includes the lower limit of quantitation (LLoQ), the Analytical Measurement Range (AMR), calibration, response linearity and stability, accuracy, precision, and specificity including epimer separation. Data from studies performed at Viollier AG comparing immunoassay-based vitamin D assay with the Cascadion SM LC-MS/MS technology evaluated of the relative performance of this integrated LC-MS/MS analyzer.
Results
Vitamin D2; Vitamin D3; Total Vitamin D
LLoQ 3.4 ng/ml; 3.4 ng/ml; 3.4 ng/ml
AMR 3.4 – 132 ng/ml; 3.4 – 132 ng/ml; 3.4 – 264 ng/ml
Stability of calibration
30 days; 30 days; 30 days
Precision 3.2 – 6.1 %CV; 2.9 – 7.6 %CV; 2.3 – 7.6 %CV
Accuracy of CDC samples for Total Vitamin D
Cascadion = 1.04 x CDC – 1.582ng/ml; R=0.9966
Conclusion
The 25-Hydroxy Vitamin D assay for Cascadion SM Clinical Analyzer delivers an analytical performance that makes it a convenient, reliable, and accurate method for assessing Vitamin D levels as well as monitoring of supplementation therapy. Stable calibration, reliable separation of epimers, and low interference from supplements such as biotin encourage the expectation that this assay on the Cascadion SM Clinical Analyzer will enable the use of LC-MS/MS in Vitamin D analysis within the routine clinical laboratory.
* Product is IVD/CE marked but not 510(k)-cleared and not yet available for sale in the U.S. Availability of product in each country depends on local regulatory marketing authorization status.
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= Discovery stage.
= Translation stage.
= Clinically available.
