Development and Certification of a Standard Reference Material for Vitamin D Metabolites in Human Serum

Analytical Chemistry Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States.
Analytical Chemistry (Impact Factor: 5.64). 12/2011; 84(2):956-62. DOI: 10.1021/ac202047n
Source: PubMed


The National Institute of Standards and Technology (NIST), in collaboration with the National Institutes of Health's Office of Dietary Supplements (NIH-ODS), has developed a Standard Reference Material (SRM) for the determination of 25-hydroxyvitamin D [25(OH)D] in serum. SRM 972 Vitamin D in Human Serum consists of four serum pools with different levels of vitamin D metabolites and has certified and reference values for 25(OH)D(2), 25(OH)D(3), and 3-epi-25(OH)D(3). Value assignment of this SRM was accomplished using a combination of three isotope-dilution mass spectrometry approaches, with measurements performed at NIST and at the Centers for Disease Control and Prevention (CDC). Chromatographic resolution of the 3-epimer of 25(OH)D(3) proved to be essential for accurate determination of the metabolites.

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Available from: Stephen A Wise, Sep 29, 2015
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    • "Participants were reviewed at recruitment for descriptive information including demographic data (age, sex, place of residence), clinical data (surgical procedure, pre-fracture and post-fracture mobility status, medications, 25-hydroxyvitamin D (25-OHD) using DiaSorin immunoassay with cross-reference to Standard Reference Materials [17,18], serum corrected calcium levels, activities of daily living (ADLs)/functional status using the Modified Barthel Index) [19], quality of life (EQ5D) [20], Mini Mental State Examination (MMSE) [21] and Clock-Drawing Tests [22], grip strength (using the participant’s dominant hand on a JAMAR hand dynamometer with maximum reading on 2 attempts [23]) and gait velocity. Weight was measured on body weight scales, whilst height measurements were taken using a ‘drop down’ tape measure fixed at about 2 metres on a wall (and from a tape measure in the supine position when weight-bearing was not possible). "
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    ABSTRACT: Background: Hypovitaminosis D is particularly common among older people with a proximal femoral (hip) fracture. There are currently no agreed strategies for vitamin D replenishment after hip fracture surgery. The REVITAHIP Study is a multisite, double-blinded randomized-controlled trial investigating the effects of an oral vitamin D loading dose on gait velocity after hip fracture surgery. We describe the baseline characteristics of participants, aiming to document hypovitaminosis D and its associations after hip fracture.
    BMC Geriatrics 09/2014; 14(1):101. DOI:10.1186/1471-2318-14-101 · 1.68 Impact Factor
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    • "In 2009, Quest Diagnostics admitted to reporting falsely high total 25-OH vitamin D results because of a poorly calibrated LC-MS/MS method [16]. However the recent introduction of traceable standards from NIST has helped to resolve this issue [11]. Another possibility is that most LC-MS/MS methods do not separate the C3-epimer of 25-OH vitamin D 2 [17] or isobars (1-α-hydroxyvitamin-D 3 [1αOHD 3 ] such as 7-α-hydroxy-4-cholesten-3-one [7αC4]) [18] which could lead to overestimation. "
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    ABSTRACT: Background: We compared total 25-OH vitamin D status measured by DiaSorin Liaison and tandem mass spectrometry (LC-MS/MS) among patients with high and low 25-OH vitamin D(2). Methods: Total 25-OH vitamin D was measured in plasma containing high (>25 nmol/l or >50%, n=26) and low (<2.5 nmol/l, n=29) 25-OH vitamin D(2) using DiaSorin Liaison and an LC-MS/MS method using NIST 972-verified calibrators. Samples were classified as vitamin D adequate (total 25-OH vitamin D ≥50 nmol/l), and inadequate or deficient (<50 nmol/l) by each method. Deming and multiple linear regression were used to compare methods. Results: Samples were significantly more likely to be classified as inadequate or deficient by DiaSorin Liaison (36%) vs LC-MS/MS (9%). This increased in the presence of high 25-OH vitamin D2 (42% vs 0%). Total 25-OH vitamin D by DiaSorin Liaison was 26.0 nmol/l lower than LC-MS/MS, which increased to 34.1 nmol/l among samples with high 25-OH vitamin D(2). This was attributed to lower recovery of 25-OH vitamin D(2) (proportional bias=0.64 nmol/l) by DiaSorin Liaison, independent of D(3) (proportional bias=0.86 nmol/l). Conclusions: Patients were more likely to be classified as vitamin D inadequate or deficient by DiaSorin Liaison compared to an LC-MS/MS method, which was in part due to the presence of 25-OH vitamin D(2).
    Clinica chimica acta; international journal of clinical chemistry 09/2012; 415C:54-58. DOI:10.1016/j.cca.2012.09.002 · 2.82 Impact Factor
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    • "There is a great deal of variety among 25-OH D assays because of the differing techniques employed for separating 25-OH D from its binding protein, its detection, and its measurement [34]. The Vitamin D Standardization program (collaboration of the NIH, the CDC, University of Ghent, and the NIST) has developed a reference method and materials will likely facilitate better agreement among vitamin D assays [11] [15]. It is expected that the manufacturers of vitamin D assays will either standardize to or be traceable to this reference method. "
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    ABSTRACT: Objectives: To evaluate the newly developed Roche MODULAR Analytics E170 Total Vitamin D and the Siemens ADVIA Centaur Vitamin D Total assays. Materials and methods: Assays were evaluated using the Clinical and Laboratory Standards Institute protocols. Split patient samples were compared with LC-MS/MS and DiaSorin LIAISON assays (n=79 including 15 specimens with detectable endogenous 25-OH vitamin D(2)). Assay accuracy was also evaluated using the Vitamin D External Quality Assessment Scheme (DEQAS) samples. Results: The ADVIA Centaur and E170 assays demonstrated maximum total CVs of 14.1% and 5.9%, respectively. Both showed excellent linearity (R(2)>0.99). The ADVIA Centaur assay demonstrated interference with bilirubin at 800 μmol/L, hemolysis at 1.25 g/L, and triglycerides at 2.8 mmol/L. Compared to LC-MS/MS, the ADVIA Centaur assay demonstrated a R(2) value of 0.893, average bias of -8.8%; the E170 assay an R(2) value of 0.872, average bias of 14.3% with underestimation of 25-OH vitamin D(2). Compared to the LIAISON assay, the ADVIA Centaur assay demonstrated an R(2) value of 0.781, average bias of -17.3%; the E170 assay an R(2) value of 0.823, average bias of 11.4%. The ADVIA Centaur and E170 assays demonstrated a biases of <20% in 10/10 and 8/10 DEQAS samples, respectively. Conclusions: The ADVIA Centaur and E170 vitamin D assays demonstrated acceptable linearity, imprecision, and accuracy. The E170 assay demonstrated consistent underestimation of 25-OH vitamin D(2) levels. Compared with LC-MS/MS, the ADVIA Centaur assay demonstrated a higher R(2) value and a smaller average bias than the E170 assay.
    Clinical biochemistry 06/2012; 45(16-17). DOI:10.1016/j.clinbiochem.2012.06.002 · 2.28 Impact Factor
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