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Wise SA, Kuszak AJ, Camara JE. Evolution and impact of Standard Reference Materials (SRMs) for determining vitamin D metabolites. Anal Bioanal Chem 2024; 416:2335-2358. [PMID: 38236394 DOI: 10.1007/s00216-024-05143-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/08/2024] [Accepted: 01/10/2024] [Indexed: 01/19/2024]
Abstract
The National Institute of Standards and Technology (NIST), in collaboration with the National Institutes of Health, Office of Dietary Supplements (NIH ODS), introduced the first Standard Reference Material® (SRM) for determining vitamin D metabolites in 2009 motivated by significant concerns about the comparability and accuracy of different assays to assess vitamin D status. After 14 years, a suite of five serum matrix SRMs and three calibration solution SRMs are available. Values were also assigned for vitamin D metabolites in five additional SRMs intended primarily to support measurements of other clinical diagnostic markers. Both the SRMs and the certification approach have evolved from significant exogenous serum content to primarily endogenous content and from value assignment by combining the results of multiple analytical methods to the use of measurements exclusively from reference measurement procedures (RMPs). The impact of the availability of these SRMs can be assessed by both the distribution information (sales) and by reports in the scientific literature describing their use for method validation, quality control, and research. In this review, we describe the development of these SRMs, the evolution in design and value assignment, the expansion of information reported, and SRM use in validating analytical methods and providing quality assurance within the vitamin D measurement community.
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Affiliation(s)
- Stephen A Wise
- Office of Dietary Supplements (ODS), National Institutes of Health (NIH), Bethesda, MD, 20817, USA.
| | - Adam J Kuszak
- Office of Dietary Supplements (ODS), National Institutes of Health (NIH), Bethesda, MD, 20817, USA
| | - Johanna E Camara
- Chemical Sciences Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD, 20899, USA
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Saito K, Goda R, Arai K, Asahina K, Kawabata M, Uchiyama H, Andou T, Shimizu H, Takahara K, Kakehi M, Yamauchi S, Nitta SI, Suga T, Fujita H, Ishikawa R, Saito Y. Interlaboratory evaluation of LC-MS-based biomarker assays. Bioanalysis 2024; 16:389-402. [PMID: 38334082 DOI: 10.4155/bio-2023-0173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2024] Open
Abstract
Validation of biomarker assays is crucial for effective drug development and clinical applications. Interlaboratory reproducibility is vital for reliable comparison and combination of data from different centers. This review summarizes interlaboratory studies of quantitative LC-MS-based biomarker assays using reference standards for calibration curves. The following points are discussed: trends in reports, reference and internal standards, evaluation of analytical validation parameters, study sample analysis and normalization of biomarker assay data. Full evaluation of these parameters in interlaboratory studies is limited, necessitating further research. Some reports suggest methods to address variations in biomarker assay data among laboratories, facilitating organized studies and data combination. Method validation across laboratories is crucial for reducing interlaboratory differences and reflecting target biomarker responses.
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Affiliation(s)
- Kosuke Saito
- National Institute of Health Sciences, Kanagawa, Japan
| | - Ryoya Goda
- Daiichi Sankyo Company Ltd, Tokyo, Japan
| | - Koji Arai
- LSI Medience Corporation, Tokyo, Japan
| | | | | | | | | | | | | | | | | | | | | | | | - Rika Ishikawa
- National Institute of Health Sciences, Kanagawa, Japan
| | - Yoshiro Saito
- National Institute of Health Sciences, Kanagawa, Japan
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Chen X, Tang J, Hu D, Jiang W, Feng J, Yang Y. C3-epi-25(OH)D3 percentage, not level, may be a potential biomarker to reflect its pathological increase in multiple diseases: a cross-sectional case-control study. Sci Rep 2023; 13:23004. [PMID: 38155294 PMCID: PMC10754939 DOI: 10.1038/s41598-023-50524-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Accepted: 12/20/2023] [Indexed: 12/30/2023] Open
Abstract
National surveys in developed countries have examined the presence of C3-epimer of 25-hydroxyvitamin D3 [C3-epi-25(OH)D3]. However, controversy remains regarding its association with disease occurrence due to its high correlation with 25-hydroxyvitamin D3 [25(OH)D3]. This study aims to investigate whether %C3-epi-25(OH)D3 can serve as an indicator for this relationship with various diseases. A total of 3086 healthy participants and 4120 patients were included in this study. We investigated the association between C3-epi-25(OH)D3 and %C3-epi-25(OH)D3 levels with gender, age, and season; compared the performance of C3-epi-25(OH)D3 and %C3-epi-25(OH)D3 across different disease conditions; and explored the correlation between %C3-epi-25(OH)D3 and various diseases. Results indicated that C3-epi-25(OH)D3 varied significantly by gender, age, and season (z/χ2 = 3.765, 10.163, and 150.975, all P < 0.01), while only season for %C3-epi-25(OH)D3 (χ2 = 233.098, P < 0.001). In contrast to the significant decrease in C3-epi-25(OH)D3, %C3-epi-25(OH)D3 showed a significant increase in 8 out of 11 disease categories (z = 3.464 ~ 11.543, all Padj < 0.05). Similar opposite changes were also observed in most of the investigated 32 specific diseases. Moreover, an elevation in %C3-epi-25(OH)D3 was found to be significantly associated with 29 specific diseases both in univariate analysis (OR = 1.16 ~ 2.10, all P < 0.05) and after adjusting for gender, age, and season (OR = 1.15 ~ 1.50, all P < 0.05). However, after further adjustment for 25(OH)D3 levels, the association remained significant only for 15 specific diseases (OR = 1.11 ~ 1.50, all P < 0.05). Seasonal stratification analysis further supports the consistent association of %C3-epi-25(OH)D3 with disease across all or nearly all four seasons. In conclusion, %C3-epi-25(OH)D3 may better reflect the production of C3-epi-25(OH)D3 in disease conditions, thereby offering a more applicable approach to investigate its association with diseases. However, the interpretation of this relationship may be confounded by 25(OH)D3 as a potential covariate.
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Affiliation(s)
- Xiaohong Chen
- Department of Laboratory Medicine, School of Medicine, Mianyang Central Hospital, University of Electronic Science and Technology of China, Mianyang, 621000, People's Republic of China
| | - Jie Tang
- Department of Laboratory Medicine, School of Medicine, Mianyang Central Hospital, University of Electronic Science and Technology of China, Mianyang, 621000, People's Republic of China
| | - Dong Hu
- Department of Laboratory Medicine, School of Medicine, Mianyang Central Hospital, University of Electronic Science and Technology of China, Mianyang, 621000, People's Republic of China
| | - Wenqiang Jiang
- Department of Laboratory Medicine, School of Medicine, Mianyang Central Hospital, University of Electronic Science and Technology of China, Mianyang, 621000, People's Republic of China
| | - Jiafu Feng
- Department of Laboratory Medicine, School of Medicine, Mianyang Central Hospital, University of Electronic Science and Technology of China, Mianyang, 621000, People's Republic of China.
| | - Yuwei Yang
- Department of Laboratory Medicine, School of Medicine, Mianyang Central Hospital, University of Electronic Science and Technology of China, Mianyang, 621000, People's Republic of China.
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Junger S, Hoene M, Shipkova M, Danzl G, Schöberl C, Peter A, Lehmann R, Wieland E, Braitmaier H. Automated LC-MS/MS: Ready for the clinical routine Laboratory? J Mass Spectrom Adv Clin Lab 2023; 30:1-9. [PMID: 37583571 PMCID: PMC10423925 DOI: 10.1016/j.jmsacl.2023.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 07/27/2023] [Accepted: 07/31/2023] [Indexed: 08/17/2023] Open
Abstract
Background Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a sensitive method with high specificity. However, its routine use in the clinical laboratory is hampered by its high complexity and lack of automation. Studies demonstrate excellent analytical performance using the first fully automated LC-MS/MS for 25-hydroxy vitamin D and immunosuppressant drugs (ISD) in hospital routine laboratories. Objectives Our objectives were (1) to verify the suitability of an automated LC-MS/MS in a commercial laboratory, which differs from the needs of hospital laboratories, and (2) examine its usability among operators with various professional backgrounds. Methods We assessed the analytical assay performance for vitamin D and the ISDs cyclosporine A and tacrolimus over five months. The assays were compared to an identical analyzer in a hospital laboratory, to in-house LC-MS/MS methods, and to chemiluminescent microparticle immunoassays (CMIA). Nine operators evaluated the usability of the fully automated LC-MS/MS system by means of a structured questionnaire. Results The automated system exhibited a high precision (CV < 8%), accuracy (bias < 7%) and good agreement with concentrations of external quality assessment (EQA) samples. Comparable results were obtained with an identical analyzer in a hospital routine laboratory. Acceptable median deviations of results versus an in-house LC-MS/MS were observed for 25-OH vitamin D3 (-10.6%), cyclosporine A (-4.3%) and tacrolimus (-6.6%). The median bias between the automated system and immunoassays was only acceptable for 25-OH vitamin D3 (6.6%). All users stated that they had had a good experience with the fully automated LC-MS/MS system. Conclusions A fully automated LC-MS/MS can be easily integrated for routine diagnostics in a commercial laboratory.
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Affiliation(s)
- Sina Junger
- SYNLAB MVZ Leinfelden-Echterdingen GmbH, Leinfelden-Echterdingen, Germany
| | - Miriam Hoene
- Institute for Clinical Chemistry and Pathobiochemistry, Department for Diagnostic Laboratory Medicine, University Hospital Tübingen, Tübingen, Germany
| | - Maria Shipkova
- SYNLAB MVZ Leinfelden-Echterdingen GmbH, Leinfelden-Echterdingen, Germany
| | | | - Christof Schöberl
- SYNLAB MVZ Leinfelden-Echterdingen GmbH, Leinfelden-Echterdingen, Germany
| | - Andreas Peter
- Institute for Clinical Chemistry and Pathobiochemistry, Department for Diagnostic Laboratory Medicine, University Hospital Tübingen, Tübingen, Germany
| | - Rainer Lehmann
- Institute for Clinical Chemistry and Pathobiochemistry, Department for Diagnostic Laboratory Medicine, University Hospital Tübingen, Tübingen, Germany
| | - Eberhard Wieland
- SYNLAB MVZ Leinfelden-Echterdingen GmbH, Leinfelden-Echterdingen, Germany
| | - Helmine Braitmaier
- SYNLAB MVZ Leinfelden-Echterdingen GmbH, Leinfelden-Echterdingen, Germany
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Burt LA, Kaufmann M, Rose MS, Jones G, Billington EO, Boyd SK, Hanley DA. Measurements of the Vitamin D Metabolome in the Calgary Vitamin D Study: Relationship of Vitamin D Metabolites to Bone Loss. J Bone Miner Res 2023; 38:1312-1321. [PMID: 37409797 DOI: 10.1002/jbmr.4876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 05/31/2023] [Accepted: 06/30/2023] [Indexed: 07/07/2023]
Abstract
In a 36-month randomized controlled trial examining the effect of high-dose vitamin D3 on radial and tibial total bone mineral density (TtBMD), measured by high-resolution peripheral quantitative tomography (HR-pQCT), participants (311 healthy males and females aged 55-70 years with dual-energy X-ray absorptiometry T-scores > -2.5 without vitamin D deficiency) were randomized to receive 400 IU (N = 109), 4000 IU (N = 100), or 10,000 IU (N = 102) daily. Participants had HR-pQCT radius and tibia scans and blood sampling at baseline, 6, 12, 24, and 36 months. This secondary analysis examined the effect of vitamin D dose on plasma measurements of the vitamin D metabolome by liquid chromatography-tandem mass spectrometry (LC-MS/MS), exploring whether the observed decline in TtBMD was associated with changes in four key metabolites [25-(OH)D3 ; 24,25-(OH)2 D3 ; 1,25-(OH)2 D3 ; and 1,24,25-(OH)3 D3 ]. The relationship between peak values in vitamin D metabolites and changes in TtBMD over 36 months was assessed using linear regression, controlling for sex. Increasing vitamin D dose was associated with a marked increase in 25-(OH)D3 , 24,25-(OH)2 D3 and 1,24,25-(OH)3 D3 , but no dose-related change in plasma 1,25-(OH)2 D3 was observed. There was a significant negative slope for radius TtBMD and 1,24,25-(OH)3 D3 (-0.05, 95% confidence interval [CI] -0.08, -0.03, p < 0.001) after controlling for sex. A significant interaction between TtBMD and sex was seen for 25-(OH)D3 (female: -0.01, 95% CI -0.12, -0.07; male: -0.04, 95% CI -0.06, -0.01, p = 0.001) and 24,25-(OH)2 D3 (female: -0.75, 95% CI -0.98, -0.52; male: -0.35, 95% CI -0.59, -0.11, p < 0.001). For the tibia there was a significant negative slope for 25-(OH)D3 (-0.03, 95% CI -0.05, -0.01, p < 0.001), 24,25-(OH)2 D3 (-0.30, 95% CI -0.44, -0.16, p < 0.001), and 1,24,25-(OH)3 D3 (-0.03, 95% CI -0.05, -0.01, p = 0.01) after controlling for sex. These results suggest vitamin D metabolites other than 1,25-(OH)2 D3 may be responsible for the bone loss seen in the Calgary Vitamin D Study. Although plasma 1,25-(OH)2 D3 did not change with vitamin D dose, it is possible rapid catabolism to 1,24,25-(OH)3 D3 prevented the detection of a dose-related rise in plasma 1,25-(OH)2 D3 . © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Lauren A Burt
- McCaig Institute for Bone and Joint Health, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Martin Kaufmann
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Marianne S Rose
- Research Facilitation, Alberta Health Services, Calgary, Alberta, Canada
| | - Glenville Jones
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Emma O Billington
- McCaig Institute for Bone and Joint Health, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Division of Endocrinology & Metabolism, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Steven K Boyd
- McCaig Institute for Bone and Joint Health, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - David A Hanley
- McCaig Institute for Bone and Joint Health, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Division of Endocrinology & Metabolism, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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Wise SA, Hahm G, Burdette CQ, Tai SSC, Camara JE, Sempos CT, Williams EL. Determination of 24,25-Dihydroxyvitamin D 3 [24,25(OH) 2D 3] in Archived Vitamin D External Quality Assessment Scheme (DEQAS) Samples using a Reference Measurement Procedure with Comparison to DEQAS Participant Results and Assessment of Contribution of 24,25(OH) 2D 3 to DEQAS Assay Results. J Steroid Biochem Mol Biol 2023; 231:106318. [PMID: 37169270 DOI: 10.1016/j.jsbmb.2023.106318] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 04/19/2023] [Accepted: 05/03/2023] [Indexed: 05/13/2023]
Abstract
Ninety archived human serum samples from the Vitamin D External Quality Assessment Scheme (DEQAS) were analyzed using a reference measurement procedure (RMP) based on isotope dilution liquid chromatography - tandem mass spectrometry (ID LC-MS/MS) for the determination of 24,25-dihydroxyvitamin D3 [24,25(OH)2D3]. These 24,25(OH)2D3 results, in conjunction with concentration values assigned using RMPs for 25-hydroxyvitamin D2 [25(OH)D2] and 25-hydroxyvitamin D3 [25(OH)D3], provide a valuable resource for assessing the accuracy of measurements for 24,25(OH)2D3 and for investigating the relationship between 24,25(OH)2D3 and 25(OH)D3. Results for 24,25(OH)2D3 using the RMP were compared to DEQAS consensus values demonstrating that the consensus values were not sufficient to assess the accuracy of measurements among different laboratories and methods. A multivariable regression analysis approach using historical DEQAS consensus values for various total 25(OH)D assays was used to assess the contribution of 24,25(OH)2D3 concentration on the assay response. The response of several ligand binding assays for total 25(OH)D was shown to be impacted by the presence of 24,25(OH)2D3.
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Affiliation(s)
- Stephen A Wise
- Office of Dietary Supplements, National Institutes of Health, Bethesda, MD 20892, USA
| | - Grace Hahm
- National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA
| | - Carolyn Q Burdette
- National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA
| | - Susan S-C Tai
- National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA
| | - Johanna E Camara
- National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA
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Herrmann M. Assessing vitamin D metabolism - four decades of experience. Clin Chem Lab Med 2023; 61:880-894. [PMID: 36639845 DOI: 10.1515/cclm-2022-1267] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 12/20/2022] [Indexed: 01/15/2023]
Abstract
One hundred years ago, the role of vitamin D for bone mineralization and the prevention of rickets was discovered. Vitamin D comprises a group of over 50 metabolites with multiple functions that go far beyond calcium homeostasis and bone mineralization. Approximately 50 years ago, first methods for the measurement of 25-hydroxyvitamin D (25(OH)D) in human blood were developed. Over the years, different analytical principals were employed including competitive protein binding assays, high-performance liquid chromatography, various immunoassay and mass spectrometric formats. Until the recent standardization of serum 25(OH)D measurement, agreement between methods was unsatisfactory. Since then, comparability has improved, but substantial variability between methods remains. With the advent of liquid chromatography tandem mass spectrometry (LC-MS/MS), the accurate determination of 25(OH)D and other metabolites, such as 24,25(OH)2D, becomes increasingly accessible for clinical laboratories. Easy access to 25(OH)D testing has triggered extensive clinical research showing that large parts of the population are vitamin D deficient. The variable response of vitamin D deficient individuals to supplementation indicates that assessing patients' vitamin D stores by measuring 25(OH)D provides limited insight into the metabolic situation. Meanwhile, first evidence has emerged suggesting that the simultaneous measurement of 25(OH)D, 24,25(OH)2D and other metabolites allows a dynamic evaluation of patients' vitamin D status on metabolic principals. This may help to identify patients with functional vitamin D deficiency from those without. It can be expected that research into the assessment vitamin D status will continue for another 50 years and that this will help rationalizing our approach in clinical practice.
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Affiliation(s)
- Markus Herrmann
- Clinical Institute of Medical and Chemical Diagnostics, Medical University of Graz, Graz, Austria
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Zhang L, Long Q, Zhang J, Zeng Q, Zhao H, Chen W, Zhang T, Zhang C. A candidate reference method and multiple commutable control materials for serum 25-hydroxyvitamin D measurement. J Clin Lab Anal 2022; 36:e24756. [PMID: 36371780 PMCID: PMC9756985 DOI: 10.1002/jcla.24756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 10/13/2022] [Accepted: 10/21/2022] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVES The aim of the current study was to establish a reliable candidate reference method for serum 25-hydroxyvitamin D [25(OH)D] measurement and to assess the commutability of multiple control materials among liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods. METHODS Serum 25-hydroxyvitamin D2 [25(OH)D2] and 25-hydroxyvitamin D3 [25(OH)D3] together with spiked internal standards were extracted with a one-step approach and then analyzed by LC-MS/MS. The commutability assessment for 25(OH)D was conducted according to the Clinical and Laboratory Standards Institute (CLSI) EP14-A3 protocol. 25(OH)D concentrations in 5 levels of unprocessed serum pools, 7 levels of serum pools spiked with 25(OH)D3 or 25(OH)D2, 3 levels of commercial control materials, 2 levels of spiked bovine serum, and 4 levels of external quality assessment (EQA) materials were measured along with 30 single-donor samples using the candidate reference method and two routine LC-MS/MS methods. RESULTS The candidate reference method could separate 25(OH)D2 and 25(OH)D3 from 14 potential interfering compounds completely within a 9-min analysis time. Good method precision was obtained, and measurement results on certified reference material NIST SRM 972a were within the uncertainty of the certified values. All candidate materials were assessed commutable for LC-MS/MS methods. CONCLUSIONS The candidate reference method for serum 25(OH)D measurement is precise, accurate, and robust against interferences and can provide an accuracy base for routine methods. The multiple alternative control materials with commutability among LC-MS/MS methods will facilitate the further standardization for serum 25(OH)D measurement.
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Affiliation(s)
- Li Zhang
- National Center for Clinical Laboratories, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology, Beijing Engineering Research Center of Laboratory MedicineChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Qichen Long
- National Center for Clinical Laboratories, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology, Beijing Engineering Research Center of Laboratory MedicineChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Jiangtao Zhang
- National Center for Clinical Laboratories, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of GerontologyBeijing Engineering Research Center of Laboratory MedicineBeijingChina
| | - Qingzhang Zeng
- National Center for Clinical Laboratories, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology, Beijing Engineering Research Center of Laboratory MedicineChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Haijian Zhao
- National Center for Clinical Laboratories, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of GerontologyBeijing Engineering Research Center of Laboratory MedicineBeijingChina
| | - Wenxiang Chen
- National Center for Clinical Laboratories, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of GerontologyBeijing Engineering Research Center of Laboratory MedicineBeijingChina
| | - Tianjiao Zhang
- National Center for Clinical Laboratories, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of GerontologyBeijing Engineering Research Center of Laboratory MedicineBeijingChina
| | - Chuanbao Zhang
- National Center for Clinical Laboratories, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of GerontologyBeijing Engineering Research Center of Laboratory MedicineBeijingChina
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Binick S, Matthews SW, Kamp KJ, Heitkemper M. Vitamin D Measurement: Clinical Practice and Research Implications. J Nurse Pract 2022. [DOI: 10.1016/j.nurpra.2022.10.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Towards harmonization of directly measured free 25-hydroxyvitamin D using an enzyme-linked immunosorbent assay. Anal Bioanal Chem 2022; 414:7793-7803. [PMID: 36109397 PMCID: PMC9568476 DOI: 10.1007/s00216-022-04313-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 08/19/2022] [Accepted: 08/31/2022] [Indexed: 11/16/2022]
Abstract
The majority of circulating 25-hydroxyvitamin D (25(OH)D) is protein bound and perhaps less available than the free fraction of 25(OH)D; therefore, researchers have proposed that the measurement of free 25(OH)D in human serum may be a better indicator of vitamin D health status than total 25(OH)D. The availability of a new enzyme-linked immunosorbent assay (ELISA) for the determination of free 25(OH)D provides a method for direct measurement of the low levels of non-protein bound 25(OH)D. As an initial step towards harmonization of measurements of free 25(OH)D, the ELISA was used to measure free 25(OH)D in three existing Standard Reference Materials (SRMs): SRM 972a Vitamin D Metabolites in Frozen Human Serum, SRM 2973 Vitamin D Metabolites in Frozen Human Serum (High Level), and SRM 1949 Frozen Prenatal Human Serum. Target values for free 25(OH)D in the nine SRM serum pools, obtained by combining the results from two laboratories, ranged from 3.76 ± 0.36 to 10.0 ± 0.58 pg/mL. Of particular significance is the assignment of free 25(OH)D target values to SRM 1949, which consists of four serum pools from non-pregnant female donors of reproductive age and pregnant women in each of the three trimesters and which also has values assigned for vitamin D binding protein, which increases during pregnancy. The availability of target values for free 25(OH)D in these SRMs will allow researchers to validate new analytical methods and to compare their results with other researchers as an initial step towards harmonization of measurements among different studies and laboratories.
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Interlaboratory comparison of 25-hydroxyvitamin D assays: Vitamin D Standardization Program (VDSP) Intercomparison Study 2 - Part 2 ligand binding assays - impact of 25-hydroxyvitamin D 2 and 24R,25-dihydroxyvitamin D 3 on assay performance. Anal Bioanal Chem 2022; 414:351-366. [PMID: 34435207 PMCID: PMC8748290 DOI: 10.1007/s00216-021-03577-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 07/15/2021] [Accepted: 07/23/2021] [Indexed: 01/03/2023]
Abstract
An interlaboratory comparison study was conducted by the Vitamin D Standardization Program (VDSP) to assess the performance of ligand binding assays (Part 2) for the determination of serum total 25-hydroxyvitamin D [25(OH)D]. Fifty single-donor samples were assigned target values for concentrations of 25-hydroxyvitamin D2 [25(OH)D2], 25-hydroxyvitamin D3 [25(OH)D3], 3-epi-25-hydroxyvitamin D3 [3-epi-25(OH)D3], and 24R,25-dihydroxyvitamin D3 [24R,25(OH)2D3] using isotope dilution liquid chromatography-tandem mass spectrometry (ID LC-MS/MS). VDSP Intercomparison Study 2 Part 2 includes results from 17 laboratories using 32 ligand binding assays. Assay performance was evaluated using mean % bias compared to the assigned target values and using linear regression analysis of the test assay mean results and the target values. Only 50% of the ligand binding assays achieved the VDSP criterion of mean % bias ≤ |± 5%|. For the 13 unique ligand binding assays evaluated in this study, only 4 assays were consistently within ± 5% mean bias and 4 assays were consistently outside ± 5% mean bias regardless of the laboratory performing the assay. Based on multivariable regression analysis using the concentrations of individual vitamin D metabolites in the 50 single-donor samples, most assays underestimate 25(OH)D2 and several assays (Abbott, bioMérieux, DiaSorin, IDS-EIA, and IDS-iSYS) may have cross-reactivity from 24R,25(OH)2D3. The results of this interlaboratory study represent the most comprehensive comparison of 25(OH)D ligand binding assays published to date and is the only study to assess the impact of 24R,25(OH)2D3 content using results from a reference measurement procedure.
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Sempos CT, Williams EL, Carter GD, Jones J, Camara JE, Burdette CQ, Hahm G, Nalin F, Duewer DL, Kuszak AJ, Merkel J, Hoofnagle AN, Lukas P, Cavalier É, Durazo-Arvizu RA, Crump PM, Popp C, Beckert C, Schultess J, Van Slooten G, Tourneur C, Pease C, Kaul R, Villarreal A, Ivison F, Fischer R, van den Ouweland JMW, Ho CS, Law EWK, Simard JN, Gonthier R, Holmquist B, Batista MC, Meadows S, Cox L, Jansen E, Khan DA, Robyak K, Creer MH, Kilbane M, Twomey PJ, Freeman J, Parker N, Yuan J, Fitzgerald R, Mushtaq S, Clarke MW, Breen N, Simpson C, Wise SA. Assessment of serum total 25-hydroxyvitamin D assays for Vitamin D External Quality Assessment Scheme (DEQAS) materials distributed at ambient and frozen conditions. Anal Bioanal Chem 2021; 414:1015-1028. [PMID: 34750644 DOI: 10.1007/s00216-021-03742-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 10/12/2021] [Accepted: 10/18/2021] [Indexed: 10/19/2022]
Abstract
The Vitamin D External Quality Assessment Scheme (DEQAS) distributes human serum samples four times per year to over 1000 participants worldwide for the determination of total serum 25-hydroxyvitamin D [25(OH)D)]. These samples are stored at -40 °C prior to distribution and the participants are instructed to store the samples frozen at -20 °C or lower after receipt; however, the samples are shipped to participants at ambient conditions (i.e., no temperature control). To address the question of whether shipment at ambient conditions is sufficient for reliable performance of various 25(OH)D assays, the equivalence of DEQAS human serum samples shipped under frozen and ambient conditions was assessed. As part of a Vitamin D Standardization Program (VDSP) commutability study, two sets of the same nine DEQAS samples were shipped to participants at ambient temperature and frozen on dry ice. Twenty-eight laboratories participated in this study and provided 34 sets of results for the measurement of 25(OH)D using 20 ligand binding assays and 14 liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods. Equivalence of the assay response for the frozen versus ambient DEQAS samples for each assay was evaluated using multi-level modeling, paired t-tests including a false discovery rate (FDR) approach, and ordinary least squares linear regression analysis of frozen versus ambient results. Using the paired t-test and confirmed by FDR testing, differences in the results for the ambient and frozen samples were found to be statistically significant at p < 0.05 for four assays (DiaSorin, DIAsource, Siemens, and SNIBE prototype). For all 14 LC-MS/MS assays, the differences in the results for the ambient- and frozen-shipped samples were not found to be significant at p < 0.05 indicating that these analytes were stable during shipment at ambient conditions. Even though assay results have been shown to vary considerably among different 25(OH)D assays in other studies, the results of this study also indicate that sample handling/transport conditions may influence 25(OH)D assay response for several assays.
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Affiliation(s)
- Christopher T Sempos
- Office of Dietary Supplements (ODS), National Institutes of Health (NIH), Bethesda, MD, 20892, USA.,Vitamin D Standardization Program LLC, Havre de Grace, MD, 21078, USA
| | | | | | - Julia Jones
- Imperial Healthcare NHS Trust, London, W6 8RF, UK
| | - Johanna E Camara
- Chemical Sciences Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD, 20899, USA
| | - Carolyn Q Burdette
- Chemical Sciences Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD, 20899, USA
| | - Grace Hahm
- Chemical Sciences Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD, 20899, USA
| | - Federica Nalin
- Chemical Sciences Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD, 20899, USA
| | - David L Duewer
- Chemical Sciences Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD, 20899, USA
| | - Adam J Kuszak
- Office of Dietary Supplements (ODS), National Institutes of Health (NIH), Bethesda, MD, 20892, USA
| | - Joyce Merkel
- Office of Dietary Supplements (ODS), National Institutes of Health (NIH), Bethesda, MD, 20892, USA
| | - Andrew N Hoofnagle
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, 98185, USA
| | - Pierre Lukas
- Clinical Chemistry, University of Liège, CHU de Liège, 4000, Liège, Belgium
| | - Étienne Cavalier
- Clinical Chemistry, University of Liège, CHU de Liège, 4000, Liège, Belgium
| | - Ramón A Durazo-Arvizu
- Biostatistics Core, The Sabin Research Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90027, USA
| | - Peter M Crump
- Computing and Biometry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Christian Popp
- Abbott Laboratories, ADD Wiesbaden Abbott GmbH, 65205, Wiesbaden, Germany
| | - Christian Beckert
- Abbott Laboratories, ADD Wiesbaden Abbott GmbH, 65205, Wiesbaden, Germany
| | - Jan Schultess
- Abbott Laboratories, ADD Wiesbaden Abbott GmbH, 65205, Wiesbaden, Germany
| | | | | | | | - Ravi Kaul
- Bio-Rad Laboratories, Clinical Diagnostics, Hercules, CA, 94547, USA
| | | | - Fiona Ivison
- Central Manchester Foundation Trust, Manchester, M13 9WL, UK
| | - Ralf Fischer
- Chromsystems Instruments & Chemicals GmbH, 82166, Gräfelfing, Germany
| | | | - Chung S Ho
- Biochemical Mass Spectrometry Unit, Department of Chemical Pathology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong, 999077
| | - Emmett W K Law
- Biochemical Mass Spectrometry Unit, Department of Chemical Pathology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong, 999077
| | | | | | - Brett Holmquist
- Endocrine Sciences, LabCorp Specialty Testing Group, Agoura Hills, CA, 91301, USA
| | | | - Sarah Meadows
- Medical Research Council (MRC) Elsie Widdowson Laboratory (Closed Dec. 2018), Cambridge, CB2 0SL, UK.,NIHR BRC Nutritional Biomarker Laboratory, MRC Epidemiology Unit, University of Cambridge, Cambridge, CB2 0SL, UK
| | - Lorna Cox
- Medical Research Council (MRC) Elsie Widdowson Laboratory (Closed Dec. 2018), Cambridge, CB2 0SL, UK.,NIHR BRC Nutritional Biomarker Laboratory, MRC Epidemiology Unit, University of Cambridge, Cambridge, CB2 0SL, UK
| | - Eugene Jansen
- National Institute of Public Health and the Environment (RIVM), 3720 BA, Bilthoven, The Netherlands
| | - Dilshad Ahmed Khan
- National University of Medical Sciences (NUMS), Rawalpindi, 46000, Punjab, Pakistan
| | - Kimberly Robyak
- College of Medicine, Penn State University, Hershey, PA, 17033, USA
| | - Michael H Creer
- College of Medicine, Penn State University, Hershey, PA, 17033, USA
| | - Mark Kilbane
- Clinical Chemistry, St. Vincent's University Hospital, Elm Park, Dublin 4, D04 T6F4, Ireland
| | - Patrick J Twomey
- Clinical Chemistry, St. Vincent's University Hospital, Elm Park, Dublin 4, D04 T6F4, Ireland
| | | | - Neil Parker
- Siemens-Healthineers, Tarrytown, NY, 10591, USA
| | - Jinyun Yuan
- SNIBE, Shenzhen, 518122, People's Republic of China
| | - Robert Fitzgerald
- Health Clinical Laboratories, University of California at San Diego, La Jolla, CA, 92093, USA
| | | | - Michael W Clarke
- Metabolomics Australia, Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, WA, 6009, Australia
| | - Norma Breen
- Waters Technologies Ireland Ltd., Wexford, Y35 D431, Ireland
| | | | - Stephen A Wise
- Office of Dietary Supplements (ODS), National Institutes of Health (NIH), Bethesda, MD, 20892, USA. .,Scientist Emeritus, National Institute of Standards and Technology (NIST), Gaithersburg, MD, 20899, USA.
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Wise SA, Camara JE, Sempos CT, Lukas P, Le Goff C, Peeters S, Burdette CQ, Nalin F, Hahm G, Durazo-Arvizu RA, Kuszak AJ, Merkel J, Cavalier É. Vitamin D Standardization Program (VDSP) intralaboratory study for the assessment of 25-hydroxyvitamin D assay variability and bias. J Steroid Biochem Mol Biol 2021; 212:105917. [PMID: 34010687 PMCID: PMC8403635 DOI: 10.1016/j.jsbmb.2021.105917] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/07/2021] [Accepted: 05/04/2021] [Indexed: 12/20/2022]
Abstract
An intralaboratory study assessing assay variability and bias for determination of serum total 25-hydroxyvitamin D [25(OH)D] was conducted by the Vitamin D Standardization Program (VDSP). Thirteen assays for serum total 25(OH)D were evaluated in a single laboratory including 11 unique immunoassays and one liquid chromatography - tandem mass spectrometry (LC-MS/MS) assay. Fifty single-donor serum samples, including eight samples with high concentrations of 25(OH)D2 (> 30 nmol/L), were assigned target values for 25(OH)D2 and 25(OH)D3 using reference measurement procedures (RMP). Using four replicate measurements for each sample, the mean total percent coefficient of variation (%CV) and mean % bias from the target values were determined for each assay using the 50 single-donor samples and a 42-sample subset, which excluded 8 high 25(OH)D2 concentration samples, and compared with VDSP performance criteria of ≤ 10 % CV and ≤ ±5 % mean bias. All 12 assays achieved the performance criterion for % CV, and 9 of the 12 assays were within ≤ ±5 % mean bias. The Fujirebio Inc. assay exhibited the lowest %CV and highest percentage of individual measurements within ≤ ±5 % mean bias. Ten immunoassays exhibited changes in response due to the high 25(OH)D2 samples with Abbott, Biomérieux, DiaSorin, DIAsource, and IDS-iSYS assays having the largest deviations. The Fujirebio Inc. and Beckman Coulter assays were only minimally affected by the presence of the high 25(OH)D2 samples. Samples with high concentrations of 25(OH)D2 provided a critical performance test for immunoassays indicating that some assays may not have equal response or recovery for 25(OH)D2 and 25(OH)D3.
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Affiliation(s)
- Stephen A Wise
- Office of Dietary Supplements (ODS), National Institutes of Health (NIH), Bethesda, MD 20892, USA; Scientist Emeritus, Associate, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA.
| | - Johanna E Camara
- Chemical Sciences Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA
| | - Christopher T Sempos
- Office of Dietary Supplements (ODS), National Institutes of Health (NIH), Bethesda, MD 20892, USA; Vitamin D Standardization Program LLC, Havre de Grace, MD 21078 USA
| | - Pierre Lukas
- Clinical Chemistry, University of Liège, CHU de Liège, B-4000 Liège, Belgium
| | - Caroline Le Goff
- Clinical Chemistry, University of Liège, CHU de Liège, B-4000 Liège, Belgium
| | - Stephanie Peeters
- Clinical Chemistry, University of Liège, CHU de Liège, B-4000 Liège, Belgium
| | - Carolyn Q Burdette
- Chemical Sciences Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA
| | - Federica Nalin
- Chemical Sciences Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA
| | - Grace Hahm
- Chemical Sciences Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA
| | - Ramón A Durazo-Arvizu
- Biostatistics Core, The Sabin Research Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90027, USA
| | - Adam J Kuszak
- Office of Dietary Supplements (ODS), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Joyce Merkel
- Office of Dietary Supplements (ODS), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Étienne Cavalier
- Clinical Chemistry, University of Liège, CHU de Liège, B-4000 Liège, Belgium
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14
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Camara JE, Wise SA, Hoofnagle AN, Williams EL, Carter GD, Jones J, Burdette CQ, Hahm G, Nalin F, Kuszak AJ, Merkel J, Durazo-Arvizu RA, Lukas P, Cavalier É, Popp C, Beckert C, Schultess J, Van Slooten G, Tourneur C, Pease C, Kaul R, Villarreal A, Ivison F, Fischer R, van den Ouweland JMW, Ho CS, Law EWK, Simard JN, Gonthier R, Holmquist B, Batista MC, Pham H, Bennett A, Meadows S, Cox L, Jansen E, Khan DA, Robyak K, Creer MH, Kilbane M, Twomey PJ, Freeman J, Parker N, Yuan J, Fitzgerald R, Mushtaq S, Clarke MW, Breen N, Simpson C, Sempos CT. Assessment of serum total 25-hydroxyvitamin D assay commutability of Standard Reference Materials and College of American Pathologists Accuracy-Based Vitamin D (ABVD) Scheme and Vitamin D External Quality Assessment Scheme (DEQAS) materials: Vitamin D Standardization Program (VDSP) Commutability Study 2. Anal Bioanal Chem 2021; 413:5067-5084. [PMID: 34184102 PMCID: PMC8431775 DOI: 10.1007/s00216-021-03470-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/29/2021] [Accepted: 06/09/2021] [Indexed: 10/21/2022]
Abstract
An interlaboratory study was conducted through the Vitamin D Standardization Program (VDSP) to assess commutability of Standard Reference Materials® (SRMs) and proficiency testing/external quality assessment (PT/EQA) samples for determination of serum total 25-hydroxyvitamin D [25(OH)D] using ligand binding assays and liquid chromatography-tandem mass spectrometry (LC-MS/MS). A set of 50 single-donor serum samples were assigned target values for 25-hydroxyvitamin D2 [25(OH)D2] and 25-hydroxyvitamin D3 [25(OH)D3] using reference measurement procedures (RMPs). SRM and PT/EQA samples evaluated included SRM 972a (four levels), SRM 2973, six College of American Pathologists (CAP) Accuracy-Based Vitamin D (ABVD) samples, and nine Vitamin D External Quality Assessment Scheme (DEQAS) samples. Results were received from 28 different laboratories using 20 ligand binding assays and 14 LC-MS/MS methods. Using the test assay results for total serum 25(OH)D (i.e., the sum of 25(OH)D2 and 25(OH)D3) determined for the single-donor samples and the RMP target values, the linear regression and 95% prediction intervals (PIs) were calculated. Using a subset of 42 samples that had concentrations of 25(OH)D2 below 30 nmol/L, one or more of the SRM and PT/EQA samples with high concentrations of 25(OH)D2 were deemed non-commutable using 5 of 11 unique ligand binding assays. SRM 972a (level 4), which has high exogenous concentration of 3-epi-25(OH)D3, was deemed non-commutable for 50% of the LC-MS/MS assays.
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Affiliation(s)
- Johanna E Camara
- Chemical Sciences Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD, 20899, USA
| | - Stephen A Wise
- Scientist Emeritus, National Institute of Standards and Technology (NIST), Gaithersburg, MD, 20899, USA.
- Office of Dietary Supplements (ODS), National Institutes of Health (NIH), Bethesda, MD, 20892, USA.
| | - Andrew N Hoofnagle
- Department of Laboratory Medicine, University of Washington, Seattle, WA, 98185, USA
| | | | | | - Julia Jones
- Imperial Healthcare NHS Trust, London, W6 8RF, UK
| | - Carolyn Q Burdette
- Chemical Sciences Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD, 20899, USA
| | - Grace Hahm
- Chemical Sciences Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD, 20899, USA
| | - Federica Nalin
- Chemical Sciences Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD, 20899, USA
| | - Adam J Kuszak
- Office of Dietary Supplements (ODS), National Institutes of Health (NIH), Bethesda, MD, 20892, USA
| | - Joyce Merkel
- Office of Dietary Supplements (ODS), National Institutes of Health (NIH), Bethesda, MD, 20892, USA
| | - Ramón A Durazo-Arvizu
- Biostatistics Core, The Sabin Research Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90027, USA
| | - Pierre Lukas
- Clinical Chemistry, University of Liège, CHU de Liège, 4000, Liège, Belgium
| | - Étienne Cavalier
- Clinical Chemistry, University of Liège, CHU de Liège, 4000, Liège, Belgium
| | - Christian Popp
- Abbott Laboratories, ADD Wiesbaden Abbott GmbH, 65205, Wiesbaden, Germany
| | - Christian Beckert
- Abbott Laboratories, ADD Wiesbaden Abbott GmbH, 65205, Wiesbaden, Germany
| | - Jan Schultess
- Abbott Laboratories, ADD Wiesbaden Abbott GmbH, 65205, Wiesbaden, Germany
| | | | | | | | - Ravi Kaul
- Clinical Diagnostics, Bio-Rad Laboratories, Clinical Diagnostics, Hercules, CA, 94547, USA
| | - Alfredo Villarreal
- Clinical Diagnostics, Bio-Rad Laboratories, Clinical Diagnostics, Hercules, CA, 94547, USA
| | - Fiona Ivison
- Central Manchester Foundation Trust, Manchester, M13 9WL, UK
| | - Ralf Fischer
- Chromsystems Instruments & Chemicals GmbH, 82166, Gräfelfing, Germany
| | | | - Chung S Ho
- Biomedical Mass Spectrometry Unit, Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, 999077, Hong Kong
| | - Emmett W K Law
- Biomedical Mass Spectrometry Unit, Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, 999077, Hong Kong
| | | | | | - Brett Holmquist
- LabCorp Specialty Testing Group, Endocrine Sciences, Agoura Hills, CA, 91301, USA
| | | | - Heather Pham
- Immunodiagnostic Systems (IDS), Boldon, NE35 9PD, UK
| | - Alex Bennett
- Immunodiagnostic Systems (IDS), Boldon, NE35 9PD, UK
| | - Sarah Meadows
- Medical Research Council (MRC) Elsie Widdowson Laboratory (closed Dec. 2018), Cambridge, CB2 0SL, UK
- NIHR BRC Nutritional Biomarker Laboratory, MRC Epidemiology Unit, University of Cambridge, Cambridge, CB2 0SL, UK
| | - Lorna Cox
- Medical Research Council (MRC) Elsie Widdowson Laboratory (closed Dec. 2018), Cambridge, CB2 0SL, UK
- NIHR BRC Nutritional Biomarker Laboratory, MRC Epidemiology Unit, University of Cambridge, Cambridge, CB2 0SL, UK
| | - Eugene Jansen
- National Institute of Public Health and the Environment (RIVM), 3720 BA, Bilthoven, The Netherlands
| | - Dilshad Ahmed Khan
- National University of Medical Sciences (NUMS), Rawalpindi, Punjab, 46000, Pakistan
| | - Kimberly Robyak
- College of Medicine, Penn State University, Hershey, PA, 17033, USA
| | - Michael H Creer
- College of Medicine, Penn State University, Hershey, PA, 17033, USA
| | - Mark Kilbane
- Clinical Chemistry, St. Vincent's University Hospital, Elm Park, Dublin 4, D04 T6F4, Ireland
| | - Patrick J Twomey
- Clinical Chemistry, St. Vincent's University Hospital, Elm Park, Dublin 4, D04 T6F4, Ireland
| | | | - Neil Parker
- Siemens-Healthineers, Tarrytown, NY, 10591, USA
| | - Jinyun Yuan
- SNIBE, Shenzhen, 518122, People's Republic of China
| | - Robert Fitzgerald
- University of California at San Diego, Health Clinical Laboratories, La Jolla, CA, 92093, USA
| | | | - Michael W Clarke
- Metabolomics Australia, Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, WA, 6009, Australia
| | - Norma Breen
- Waters Technologies Ireland Ltd., Wexford, Y35 D431, Ireland
| | | | - Christopher T Sempos
- Office of Dietary Supplements (ODS), National Institutes of Health (NIH), Bethesda, MD, 20892, USA
- Vitamin D Standardization Program LLC, Havre de Grace, MD, 21078, USA
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