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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] [What about the content of this article? (0)] [Affiliation(s)] [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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2
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Sandberg S, Fauskanger P, Johansen JV, Keller T, Budd J, Greenberg N, Rej R, Panteghini M, Delatour V, Ceriotti F, Deprez L, Camara JE, MacKenzie F, Lyle AN, van der Hagen E, Burns C, Greg Miller W. Recommendations for Setting a Criterion and Assessing Commutability of Sample Materials Used in External Quality Assessment/Proficiency Testing Schemes. Clin Chem 2023; 69:1227-1237. [PMID: 37725906 DOI: 10.1093/clinchem/hvad135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 08/21/2023] [Indexed: 09/21/2023]
Abstract
It is important for external quality assessment materials (EQAMs) to be commutable with clinical samples; i.e., they should behave like clinical samples when measured using end-user clinical laboratory in vitro diagnostic medical devices (IVD-MDs). Using commutable EQAMs makes it possible to evaluate metrological traceability and/or equivalence of results between IVD-MDs. The criterion for assessing commutability of an EQAM between 2 IVD-MDs is that its result should be within the prediction interval limits based on the statistical distribution of the clinical sample results from the 2 IVD-MDs being compared. The width of the prediction interval is, among other things, dependent on the analytical performance characteristics of the IVD-MDs. A presupposition for using this criterion is that the differences in nonselectivity between the 2 IVD-MDs being compared are acceptable. An acceptable difference in nonselectivity should be small relative to the analytical performance specifications used in the external quality assessment scheme. The acceptable difference in nonselectivity is used to modify the prediction interval criterion for commutability assessment. The present report provides recommendations on how to establish a criterion for acceptable commutability for EQAMS, establish the difference in nonselectivity that can be accepted between IVD-MDs, and perform a commutability assessment. The report also contains examples for performing a commutability assessment of EQAMs.
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Affiliation(s)
- Sverre Sandberg
- Norwegian Organization for Quality Improvement of Laboratory Examinations (Noklus), Haraldsplass Deaconess Hospital, Bergen, Norway
- Norwegian Porphyria Centre, Department of Medical Biochemistry and Pharmacology, Haukeland University Hospital, Bergen, Norway
- Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway
| | - Pernille Fauskanger
- Norwegian Organization for Quality Improvement of Laboratory Examinations (Noklus), Haraldsplass Deaconess Hospital, Bergen, Norway
| | | | | | - Jeffrey Budd
- Jeff Budd Consulting, St. Paul, MN, United States
| | - Neil Greenberg
- Neil Greenberg Consulting, LLC, Rochester, NY, United States
| | - Robert Rej
- Department of Biomedical Sciences, School of Public Health, State University of New York at Albany, Albany, NY, United States
| | - Mauro Panteghini
- Research Centre for Metrological Traceability in Laboratory Medicine, University of Milan, Milan, Italy
| | | | | | - Liesbet Deprez
- European Commission, Joint Research Centre, Directorate F, Geel, Belgium
| | - Johanna E Camara
- National Institute of Standards and Technology, Gaithersburg, MD, United States
| | - Finlay MacKenzie
- Birmingham Quality/UK NEQAS, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - Alicia N Lyle
- Centers for Disease Control and Prevention, Atlanta, GA, United States
| | | | - Chris Burns
- National Institute for Biological Standards and Control, A Centre of the MHRA, Hertfordshire, United Kingdom
| | - W Greg Miller
- Virginia Commonwealth University, Richmond, VA, United States
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Miller WG, Keller T, Budd J, Johansen JV, Panteghini M, Greenberg N, Delatour V, Ceriotti F, Deprez L, Rej R, Camara JE, MacKenzie F, Lyle AN, van der Hagen E, Burns C, Fauskanger P, Sandberg S. Recommendations for Setting a Criterion for Assessing Commutability of Secondary Calibrator Certified Reference Materials. Clin Chem 2023; 69:966-975. [PMID: 37566391 DOI: 10.1093/clinchem/hvad104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 06/12/2023] [Indexed: 08/12/2023]
Abstract
A secondary higher-order calibrator is required to be commutable with clinical samples to be suitable for use in the calibration hierarchy of an end-user clinical laboratory in vitro diagnostic medical device (IVD-MD). Commutability is a property of a reference material that means results for a reference material and for clinical samples have the same numeric relationship, within specified limits, across the measurement procedures for which the reference material is intended to be used. Procedures for assessing commutability have been described in the literature. This report provides recommendations for establishing a quantitative criterion to assess the commutability of a certified reference material (CRM). The criterion is the maximum allowable noncommutability bias (MANCB) that allows a CRM to be used as a calibrator in a calibration hierarchy for an IVD-MD without exceeding the maximum allowable combined standard uncertainty for a clinical sample result (umaxCS). Consequently, the MANCB is derived as a fraction of the umaxCS for the measurand. The suitability of an MANCB for practical use in a commutability assessment is determined by estimating the number of measurements of clinical samples and CRMs required based on the precision performance and nonselectivity for the measurand of the measurement procedures in the assessment. Guidance is also provided for evaluating indeterminate commutability conclusions and how to report results of a commutability assessment.
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Affiliation(s)
- W Greg Miller
- Department of Pathology, Virginia Commonwealth University, Richmond, VA, United States
| | | | - Jeffrey Budd
- Jeff Budd Consulting, St. Paul, MN, United States
| | | | - Mauro Panteghini
- Research Centre for Metrological Traceability in Laboratory Medicine, University of Milan, Milan, Italy
| | - Neil Greenberg
- Neil Greenberg Consulting, LLC, Rochester, NY, United States
| | | | | | - Liesbet Deprez
- European Commission, Joint Research Centre, Directorate F, Geel, Belgium
| | - Robert Rej
- Department of Biomedical Sciences, School of Public Health, University at Albany, State University of New York, Albany, NY, United States
| | - Johanna E Camara
- National Institute of Standards and Technology, Gaithersburg, MD, United States
| | - Finlay MacKenzie
- Birmingham Quality/UK NEQAS, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - Alicia N Lyle
- Centers for Disease Control and Prevention, Atlanta, GA, United States
| | | | - Chris Burns
- National Institute for Biological Standards and Control, A Centre of the MHRA, Hertfordshire, United Kingdom
| | - Pernille Fauskanger
- Norwegian Organization for Quality Improvement of Laboratory Examinations (Noklus), Haraldsplass Deaconess Hospital, Bergen, Norway
| | - Sverre Sandberg
- Norwegian Organization for Quality Improvement of Laboratory Examinations (Noklus), Haraldsplass Deaconess Hospital, Bergen, Norway
- Norwegian Porphyria Centre, Department of Medical Biochemistry and Pharmacology, Haukeland University Hospital, Bergen, Norway
- Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Panteghini M, Braga F, Camara JE, Delatour V, Van Uytfanghe K, Vesper HW, Zhang T. Optimizing Available Tools for Achieving Result Standardization: Value Added by Joint Committee on Traceability in Laboratory Medicine (JCTLM). Clin Chem 2021; 67:1590-1605. [PMID: 34633037 DOI: 10.1093/clinchem/hvab178] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 08/12/2021] [Indexed: 12/14/2022]
Abstract
BACKGROUND The JCTLM created a Task Force on Reference Measurement System Implementation (TF-RMSI) to provide guidance on metrological traceability implementation for the in vitro diagnostics (IVD) community. CONTENT TF-RMSI investigated the reference measurement systems (RMS) for 13 common measurands by applying the following procedural steps: (a) extracting data from the JCTLM database of available certified reference materials (CRMs) and reference measurement procedures (RMPs); (b) describing the RMS to which each recruited CRM or RMP belongs; (c) identifying the intended use of the CRMs, and, if used as a common calibrator for IVD measuring systems and/or trueness assessment of field methods was included, checking the CRM's certificate for information about commutability with clinical samples; and (d) checking if the CRM or RMP measurement uncertainty (MU) has the potential to be small enough to avoid significantly affecting the analytical performance specifications (APS) for MU of clinical sample results when the MU from the IVD calibrator and from the end-user measuring system were combined. SUMMARY We produced a synopsis of JCTLM-listed higher-order CRMs and RMPs for the selected measurands, including their main characteristics for implementing traceability and fulfilling (or not) the APS for suitable MU. Results showed that traceability to higher-order references can be established by IVD manufacturers within the defined APS for most of the 13 selected measurands. However, some measurands do not yet have suitable CRMs for use as common calibrators. For these measurands, splitting clinical samples with a laboratory performing the RMP may provide a practical alternative for establishing a calibration hierarchy.
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Affiliation(s)
- Mauro Panteghini
- 'L. Sacco' Department of Biomedical and Clinical Sciences, Research Centre for Metrological Traceability in Laboratory Medicine (CIRME), University of Milan, Milano, Italy
| | - Federica Braga
- 'L. Sacco' Department of Biomedical and Clinical Sciences, Research Centre for Metrological Traceability in Laboratory Medicine (CIRME), University of Milan, Milano, Italy
| | - Johanna E Camara
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD
| | - Vincent Delatour
- Chemistry and Biology Division, Laboratoire National de Metrologie et d'Essais (LNE), Paris, France
| | - Katleen Van Uytfanghe
- Ref4U-Laboratory of Toxicology, Department of Bioanalysis, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium
| | - Hubert W Vesper
- Division of Laboratory Sciences, Centers for Disease Control and Prevention, Atlanta, GA
| | - Tianjiao Zhang
- Division of clinical chemistry, National Center for Clinical Laboratories, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, China
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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8
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Wise SA, Camara JE, Burdette CQ, Hahm G, Nalin F, Kuszak AJ, Merkel J, Durazo-Arvizu RA, Williams EL, Hoofnagle AN, Ivison F, Fischer R, van den Ouweland JMW, Ho CS, Law EWK, Simard JN, Gonthier R, Holmquist B, Meadows S, Cox L, Robyak K, Creer MH, Fitzgerald R, Clarke MW, Breen N, Lukas P, Cavalier É, Sempos CT. Interlaboratory comparison of 25-hydroxyvitamin D assays: Vitamin D Standardization Program (VDSP) Intercomparison Study 2 - Part 1 liquid chromatography - tandem mass spectrometry (LC-MS/MS) assays - impact of 3-epi-25-hydroxyvitamin D 3 on assay performance. Anal Bioanal Chem 2021; 414:333-349. [PMID: 34432104 DOI: 10.1007/s00216-021-03576-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 07/15/2021] [Accepted: 07/23/2021] [Indexed: 12/19/2022]
Abstract
An interlaboratory comparison study was conducted by the Vitamin D Standardization Program (VDSP) to assess the performance of liquid chromatography - tandem mass spectrometry (LC-MS/MS) assays used for the determination of serum total 25-hydroxyvitamin D (25(OH)D), which is the sum of 25-hydroxyvitamin D2 (25(OH)D2) and 25-hydroxyvitamin D3 (25(OH)D3). A set of 50 single-donor samples was assigned target values for concentrations of 25(OH)D2, 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 1 includes results from 14 laboratories using 14 custom LC-MS/MS 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 53% of the LC-MS/MS assays met the VDSP criterion of mean % bias ≤ |±5%|. For the LC-MS/MS assays not meeting the ≤ |±5%| criterion, four assays had mean % bias of between 12 and 21%. Based on multivariable regression analysis using the concentrations of the four individual vitamin D metabolites in the 50 single-donor samples, the performance of several LC-MS/MS assays was found to be influenced by the presence of 3-epi-25(OH)D3. The results of this interlaboratory study represent the most comprehensive comparison of LC-MS/MS assay performance for serum total 25(OH)D and document the significant impact of the lack of separation of 3-epi-25(OH)D3 and 25(OH)D3 on assay performance, particularly with regard to mean % bias.
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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, 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
| | - 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
| | | | - Andrew N Hoofnagle
- Department of Laboratory Medicine, University of Washington, Seattle, WA, 98185, 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, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, 999077, Hong Kong
| | - Emmett W K Law
- Biochemical Mass Spectrometry Unit, Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, 999077, Hong Kong
| | | | | | - 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, 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, UK.,NIHR BRC Nutritional Biomarker Laboratory, MRC Epidemiology Unit, University of Cambridge, Cambridge, CB2 0SL, UK
| | - 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
| | - 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
| | - Pierre Lukas
- Clinical Chemistry, University of Liège, CHU de Liège, B-4000, Liège, Belgium
| | - Étienne Cavalier
- Clinical Chemistry, University of Liège, CHU de Liège, B-4000, Liège, Belgium
| | - 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, 217078, USA
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9
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Danilenko U, Vesper HW, Myers GL, Clapshaw PA, Camara JE, Miller WG. An updated protocol based on CLSI document C37 for preparation of off-the-clot serum from individual units for use alone or to prepare commutable pooled serum reference materials. Clin Chem Lab Med 2021; 58:368-374. [PMID: 31665109 DOI: 10.1515/cclm-2019-0732] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 09/20/2019] [Indexed: 11/15/2022]
Abstract
Manufacturers of in vitro diagnostic medical devices, clinical laboratories, research laboratories and calibration laboratories require commutable reference materials that can be used in the calibration hierarchies of medical laboratory measurement procedures used for human specimens to establish metrological traceability to higher order reference systems. Commutable materials are also useful in external quality assessment surveys. In order to achieve these goals, matrix-based reference materials with long-term stability, appropriate measurand concentrations and commutability with individual human specimens are required. The Clinical and Laboratory Standards Institute (CLSI) guideline C37-A (now archived) provided guidance to prepare commutable pooled serum reference materials for use in the calibration hierarchies of cholesterol measurement procedures. Experience using the C37-A guideline has identified a number of technical enhancements as well as applications to measurands other than cholesterol. This experience is incorporated into this updated protocol to ensure the procedure will continue to meet the needs of the medical laboratory. The updated protocol describes a procedure for preparing frozen human serum units or pools with minimal matrix alterations that are likely to be commutable with individual human serum samples. The protocol provides step-by-step guidance for the planning phase, collection of individual serum units, processing the units, qualifying the units for use in a pool and frozen storage of aliquots of pooled sera to manufacture frozen serum pools. Guidance on how to perform quality control of the final product and suggestions on documentation are also provided.
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Affiliation(s)
- Uliana Danilenko
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Hwy NE, MS F25, Atlanta, GA 30341, USA, Phone: +770-488-7346
| | - Hubert W Vesper
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA
| | | | | | - Johanna E Camara
- National Institute of Standards and Technology, Gaithersburg, MD, USA
| | - W Greg Miller
- Department of Pathology, Virginia Commonwealth University, Richmond, VA, USA
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11
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Miller WG, Budd J, Greenberg N, Weykamp C, Althaus H, Schimmel H, Panteghini M, Delatour V, Ceriotti F, Keller T, Hawkins D, Burns C, Rej R, Camara JE, MacKenzie F, van der Hagen E, Vesper H. IFCC Working Group Recommendations for Correction of Bias Caused by Noncommutability of a Certified Reference Material Used in the Calibration Hierarchy of an End-User Measurement Procedure. Clin Chem 2021; 66:769-778. [PMID: 32335671 DOI: 10.1093/clinchem/hvaa048] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 02/06/2020] [Indexed: 11/14/2022]
Abstract
Establishing metrological traceability to an assigned value of a matrix-based certified reference material (CRM) that has been validated to be commutable among available end-user measurement procedures (MPs) is central to producing equivalent results for the measurand in clinical samples (CSs) irrespective of the clinical laboratory MPs used. When a CRM is not commutable with CSs, the bias due to noncommutability will be propagated to the CS results causing incorrect metrological traceability to the CRM and nonequivalent CS results among different MPs. In a commutability assessment, a conclusion that a CRM is commutable or noncommutable for use with a specific MP is made when the difference in bias between the CRM and CSs meets or does not meet a criterion for that specific MP when compared to other MPs. A conclusion regarding commutability or noncommutability requires that the magnitude of the difference in bias observed in the commutability assessment remains unchanged over time. This conclusion requires the CRM to be stable and no substantive changes in the MPs. These conditions should be periodically reverified. If an available CRM is determined to be noncommutable for a specific MP, that CRM can be used in the calibration hierarchy for that MP when an appropriately validated MP-specific correction for the noncommutability bias is included. We describe with examples how a MP-specific correction and its uncertainty can be developed and applied in a calibration hierarchy to achieve metrological traceability of results for CSs to the CRM's assigned value.
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Affiliation(s)
| | | | | | - Cas Weykamp
- Queen Beatrix Hospital, Winterswijk, the Netherlands
| | - Harald Althaus
- Siemens Healthcare Diagnostics Products GmbH, Marburg, Germany
| | - Heinz Schimmel
- European Commission, Joint Research Centre, Directorate F, Geel, Belgium
| | - Mauro Panteghini
- Research Centre for Metrological Traceability in Laboratory Medicine (CIRME), University of Milan, Milan, Italy
| | - Vincent Delatour
- Laboratoire national de métrologie et d'essais (LNE), Paris, France
| | | | | | - Douglas Hawkins
- School of Statistics, University of Minnesota, Minneapolis, MN
| | - Chris Burns
- National Institute for Biological Standards and Control, A Centre of the MHRA, Hertfordshire, UK
| | - Robert Rej
- Wadsworth Center for Laboratories and Research, New York State Department of Health, and School of Public Health State University of New York at Albany, Albany, NY
| | - Johanna E Camara
- National Institute of Standards and Technology, Gaithersburg, MD
| | - Finlay MacKenzie
- Birmingham Quality/UK NEQAS, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | | | - Hubert Vesper
- Centers for Disease Control and Prevention, Atlanta, GA
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12
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Teo TL, Lippa KA, Mackay L, Yong S, Liu Q, Camara JE, Delatour V, Lee TK, Lalere B, O' Connor G, Henrion A, Kato M, Numata M, Kwon HJ, Jeong JS, Xu B, Song D, Nammoonnoy J, Wollinger W. Enhancing the accuracy of measurement of small molecule organic biomarkers. Anal Bioanal Chem 2019; 411:7341-7355. [PMID: 31667564 PMCID: PMC11087866 DOI: 10.1007/s00216-019-02153-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/21/2019] [Accepted: 09/12/2019] [Indexed: 10/25/2022]
Abstract
Over two decades, the Organic Analysis Working Group (OAWG) of the Consultative Committee for Amount of Substance: Metrology in Chemistry and Biology (CCQM) has organized a number of comparisons for clinically relevant small molecule organic biomarkers. The aim of the OAWG community is to be part of the coordinated international movement towards accuracy and comparability of clinical measurements that will, in turn, minimize the wastage of repeat testing and unnecessary therapy to create a sustainable healthcare industry. International and regional directives/requirements on metrological traceability of calibrators and control materials are in place. Metrology institutes worldwide maintain infrastructure for the practical realization of metrological traceability and demonstrate the equivalence of their measurement capabilities through participation in key comparisons organized under the auspices of the CCQM. These institutes provide certified reference materials, as well as other dedicated value-assignment services benefiting the in-vitro diagnostic (IVD) industry, reference (calibration) laboratories and the clinical chemistry laboratories. The roles of these services in supporting national, regional, and international activities to ensure the metrological traceability of clinical chemistry measurements are described. Graphical abstract.
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Affiliation(s)
- Tang Lin Teo
- Chemical Metrology Laboratory, Applied Sciences Group, Health Science Authority (HSA), 1 Science Park Road, The Capricorn, Science Park II, Singapore, 117528, Singapore.
| | - Katrice A Lippa
- National Institute of Standards and Technology (NIST), 100 Bureau Drive, Gaithersburg, MD, 20899, USA
| | - Lindsey Mackay
- National Measurement Institute Australia (NMIA), 105 Delhi Rd, North Ryde, NSW, 2113, Australia
| | - Sharon Yong
- Chemical Metrology Laboratory, Applied Sciences Group, Health Science Authority (HSA), 1 Science Park Road, The Capricorn, Science Park II, Singapore, 117528, Singapore
| | - Qinde Liu
- Chemical Metrology Laboratory, Applied Sciences Group, Health Science Authority (HSA), 1 Science Park Road, The Capricorn, Science Park II, Singapore, 117528, Singapore
| | - Johanna E Camara
- National Institute of Standards and Technology (NIST), 100 Bureau Drive, Gaithersburg, MD, 20899, USA
| | - Vincent Delatour
- Laboratoire National De Métrologie Et D'essais (LNE), 1 Rue Gaston Boissier, 75015, Paris, France
| | - Tong Kooi Lee
- Chemical Metrology Laboratory, Applied Sciences Group, Health Science Authority (HSA), 1 Science Park Road, The Capricorn, Science Park II, Singapore, 117528, Singapore
| | - Béatrice Lalere
- Laboratoire National De Métrologie Et D'essais (LNE), 1 Rue Gaston Boissier, 75015, Paris, France
| | - Gavin O' Connor
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany
| | - André Henrion
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany
| | - Megumi Kato
- National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki, 305-8563, Japan
| | - Masahiko Numata
- National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki, 305-8563, Japan
| | - Ha-Jeong Kwon
- Korea Research Institute of Standards and Science (KRISS), 267 Gajeong-ro, Yuseong-gu, Daejeon, 34113, Republic of Korea
| | - Ji-Seon Jeong
- Korea Research Institute of Standards and Science (KRISS), 267 Gajeong-ro, Yuseong-gu, Daejeon, 34113, Republic of Korea
| | - Bei Xu
- National Institute of Metrology, China (NIM), No.18, Bei San Huang Dong Lu, Chaoyang District, Beijing, 100029, China
| | - Dewei Song
- National Institute of Metrology, China (NIM), No.18, Bei San Huang Dong Lu, Chaoyang District, Beijing, 100029, China
| | - Jintana Nammoonnoy
- National Institute of Metrology, Thailand (NIMT), Technopolis Campus, 3/4-5 Moo 3, Klong 5, Klong Luang, Pathumthani, 12120, Thailand
| | - Wagner Wollinger
- Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMETRO), 50 N Sra das Gracas, Duque de Caxias, Rio de Janeiro, 25250-020, Brazil
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Benner BA, Schantz MM, Powers CD, Schleicher RL, Camara JE, Sharpless KE, Yen JH, Sniegoski LT. Standard Reference Material (SRM) 2378 fatty acids in frozen human serum. Certification of a clinical SRM based on endogenous supplementation of polyunsaturated fatty acids. Anal Bioanal Chem 2018; 410:2321-2329. [PMID: 29435636 PMCID: PMC5851844 DOI: 10.1007/s00216-017-0841-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 12/01/2017] [Accepted: 12/18/2017] [Indexed: 10/18/2022]
Abstract
Dietary fatty acids can be both beneficial and detrimental to human health depending on the degree and type of saturation. Healthcare providers and research scientists monitor the fatty acid content of human plasma and serum as an indicator of health status and diet. In addition, both the Centers for Disease Control & Prevention (CDC) and the National Institutes of Health - Office of Dietary Supplements are interested in circulating fatty acids (FAs) because they may be predictive of coronary heart disease. The National Institute of Standards and Technology (NIST) provides a wide variety of reference materials (RMs) and Standard Reference Materials® (SRM®s) including blood, serum, plasma, and urine with values assigned for analytes of clinical interest. NIST SRM 2378 Fatty Acids in Frozen Human Serum was introduced in 2015 to help validate methods used for the analysis of FAs in serum, and consists of three different pools of serum acquired from (1) healthy donors who had taken fish oil dietary supplements (at least 1000 mg per day) for at least one month (level 1 material), (2) healthy donors who had taken flaxseed oil dietary supplements (at least 1000 mg per day) for at least one month (level 2 material), and (3) healthy donors eating "normal" diets who had not taken dietary supplements containing fish or plant oils (level 3 material). The use of dietary supplements by donors provided SRMs with natural endogenous ranges of FAs at concentrations observed in human populations. Results from analyses using two methods at NIST, including one involving a novel microwave-assisted acid hydrolysis procedure, and one at the CDC are presented here. These results and their respective uncertainties were combined to yield certified values with expanded uncertainties for 12 FAs and reference values with expanded uncertainties for an additional 18 FAs.
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Affiliation(s)
- Bruce A Benner
- Chemical Sciences Division, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD, 20899, USA.
| | - Michele M Schantz
- Chemical Sciences Division, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD, 20899, USA
| | - Carissa D Powers
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Hwy, Atlanta, GA, 30341, USA
| | - Rosemary L Schleicher
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Hwy, Atlanta, GA, 30341, USA
| | - Johanna E Camara
- Chemical Sciences Division, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD, 20899, USA
| | - Katherine E Sharpless
- Chemical Sciences Division, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD, 20899, USA
| | - James H Yen
- Statistical Engineering Division, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD, 20899, USA
| | - Lorna T Sniegoski
- Chemical Sciences Division, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD, 20899, USA
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14
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Miller WG, Schimmel H, Rej R, Greenberg N, Ceriotti F, Burns C, Budd JR, Weykamp C, Delatour V, Nilsson G, MacKenzie F, Panteghini M, Keller T, Camara JE, Zegers I, Vesper HW. IFCC Working Group Recommendations for Assessing Commutability Part 1: General Experimental Design. Clin Chem 2018; 64:447-454. [PMID: 29348163 DOI: 10.1373/clinchem.2017.277525] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 12/14/2017] [Indexed: 11/06/2022]
Abstract
Commutability is a property of a reference material (RM) that relates to the closeness of agreement between results for an RM and results for clinical samples (CSs) when measured by ≥2 measurement procedures (MPs). Commutability of RMs used in a calibration traceability scheme is an essential property for them to be fit for purpose. Similarly, commutability of trueness controls or external quality assessment samples is essential when those materials are used to assess trueness of results for CSs. This report is part 1 of a 3-part series describing how to assess commutability of RMs. Part 1 defines commutability and addresses critical components of the experimental design for commutability assessment, including selection of individual CSs, use of pooled CSs, qualification of MPs for inclusion, establishing criteria for the determination that an RM is commutable, generalization of commutability conclusions to future measurements made with the MPs included in the assessment, and information regarding commutability to be included in the certificate for an RM. Parts 2 and 3 in the series present 2 different statistical approaches to commutability assessment that use fixed criteria related to the medical decisions that will be made using the laboratory test results.
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Affiliation(s)
- W Greg Miller
- Department of Pathology, Virginia Commonwealth University, Richmond, VA;
| | - Heinz Schimmel
- European Commission, Joint Research Centre (JRC), Directorate F, Geel, Belgium
| | - Robert Rej
- Wadsworth Center for Laboratories and Research, New York State Department of Health, and School of Public Health, State University of New York at Albany, Albany, NY
| | | | | | - Chris Burns
- National Institute for Biological Standards and Control, A Centre of the MHRA, Hertfordshire, UK
| | | | - Cas Weykamp
- Queen Beatrix Hospital, Winterswijk, the Netherlands
| | - Vincent Delatour
- Laboratoire national de métrologie et d'essais (LNE), Paris, France
| | | | - Finlay MacKenzie
- Birmingham Quality/UK NEQAS, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Mauro Panteghini
- Research Centre for Metrological Traceability in Laboratory Medicine (CIRME), University of Milan, Milan, Italy
| | | | - Johanna E Camara
- National Institute of Standards and Technology, Gaithersburg, MD
| | - Ingrid Zegers
- European Commission, Joint Research Centre (JRC), Directorate F, Geel, Belgium
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15
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Nilsson G, Budd JR, Greenberg N, Delatour V, Rej R, Panteghini M, Ceriotti F, Schimmel H, Weykamp C, Keller T, Camara JE, Burns C, Vesper HW, MacKenzie F, Miller WG. IFCC Working Group Recommendations for Assessing Commutability Part 2: Using the Difference in Bias between a Reference Material and Clinical Samples. Clin Chem 2018; 64:455-464. [PMID: 29348165 DOI: 10.1373/clinchem.2017.277541] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 12/15/2017] [Indexed: 11/06/2022]
Abstract
A process is described to assess the commutability of a reference material (RM) intended for use as a calibrator, trueness control, or external quality assessment sample based on the difference in bias between an RM and clinical samples (CSs) measured using 2 different measurement procedures (MPs). This difference in bias is compared with a criterion based on a medically relevant difference between an RM and CS results to make a conclusion regarding commutability. When more than 2 MPs are included, the commutability is assessed pairwise for all combinations of 2 MPs. This approach allows the same criterion to be used for all combinations of MPs included in the assessment. The assessment is based on an error model that allows estimation of various random and systematic sources of error, including those from sample-specific effects of interfering substances. An advantage of this approach is that the difference in bias between an RM and the average bias of CSs at the concentration (i.e., amount of substance present or quantity value) of the RM is determined and its uncertainty estimated. An RM is considered fit for purpose for those MPs for which commutability is demonstrated.
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Affiliation(s)
| | | | | | - Vincent Delatour
- Laboratoire national de métrologie et d'essais (LNE), Paris, France
| | - Robert Rej
- Wadsworth Center for Laboratories and Research, New York State Department of Health, and School of Public Health, State University of New York at Albany, Albany, NY
| | - Mauro Panteghini
- Research Centre for Metrological Traceability in Laboratory Medicine (CIRME), University of Milan, Milan, Italy
| | | | - Heinz Schimmel
- European Commission, Joint Research Centre (JRC), Directorate F, Geel, Belgium
| | - Cas Weykamp
- Queen Beatrix Hospital, Winterswijk, the Netherlands
| | | | - Johanna E Camara
- National Institute of Standards and Technology, Gaithersburg, MD
| | - Chris Burns
- National Institute for Biological Standards and Control, A Centre of the MHRA, Hertfordshire, UK
| | | | - Finlay MacKenzie
- Birmingham Quality/UK NEQAS, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - W Greg Miller
- Department of Pathology, Virginia Commonwealth University, Richmond, VA.
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16
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Budd JR, Weykamp C, Rej R, MacKenzie F, Ceriotti F, Greenberg N, Camara JE, Schimmel H, Vesper HW, Keller T, Delatour V, Panteghini M, Burns C, Miller WG. IFCC Working Group Recommendations for Assessing Commutability Part 3: Using the Calibration Effectiveness of a Reference Material. Clin Chem 2018; 64:465-474. [PMID: 29348164 DOI: 10.1373/clinchem.2017.277558] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 12/18/2017] [Indexed: 11/06/2022]
Abstract
A process is described to assess the commutability of a reference material (RM) intended for use as a calibrator based on its ability to fulfill its intended use in a calibration traceability scheme to produce equivalent clinical sample (CS) results among different measurement procedures (MPs) for the same measurand. Three sources of systematic error are elucidated in the context of creating the calibration model for translating MP signals to measurand amounts: calibration fit, calibrator level trueness, and commutability. An example set of 40 CS results from 7 MPs is used to illustrate estimation of bias and variability for each MP. The candidate RM is then used to recalibrate each MP, and its effectiveness in reducing the systematic error among the MPs within an acceptable level of equivalence based on medical requirements confirms its commutability for those MPs. The RM is declared noncommutable for MPs for which, after recalibration, the CS results do not agree with those from other MPs. When a lack of agreement is found, other potential causes, including lack of calibration fit, should be investigated before concluding the RM is noncommutable. The RM is considered fit for purpose for those MPs where commutability is demonstrated.
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Affiliation(s)
| | - Cas Weykamp
- Queen Beatrix Hospital, Winterswijk, the Netherlands
| | - Robert Rej
- Wadsworth Center for Laboratories and Research, New York State Department of Health, and School of Public Health, State University of New York at Albany, Albany, NY
| | - Finlay MacKenzie
- Birmingham Quality/UK NEQAS, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | | | | | - Johanna E Camara
- National Institute of Standards and Technology, Gaithersburg, MD
| | - Heinz Schimmel
- European Commission, Joint Research Centre (JRC), Directorate F, Geel, Belgium
| | | | | | - Vincent Delatour
- Laboratoire national de métrologie et d'essais (LNE), Paris, France
| | - Mauro Panteghini
- Research Centre for Metrological Traceability in Laboratory Medicine (CIRME), University of Milan, Milan, Italy
| | - Chris Burns
- National Institute for Biological Standards and Control, A Centre of the MHRA, Hertfordshire, UK
| | - W Greg Miller
- Department of Pathology, Virginia Commonwealth University, Richmond, VA.
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17
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Phinney KW, Camara JE, Tai SSC, Sander LC, Wise SA, De Grande LAC, Thienpont LM, Possolo AM, Toman B, Sempos CT, Betz JM, Coates PM. Value Assignment of Vitamin D Metabolites in Vitamin D Standardization Program Serum Samples. J AOAC Int 2017; 100:1253-1259. [PMID: 28623654 PMCID: PMC5601309 DOI: 10.5740/jaoacint.17-0204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Assay variability has been cited as an obstacle to establishing optimal vitamin D exposure. As part of the Vitamin D Standardization Program (VDSP) effort to standardize the measurement of total 25-hydroxyvitamin D [25(OH)D], the value assignment of total 25(OH)D in 50 single-donor serum samples was performed using two isotope-dilution LC with tandem MS methods. Both methods are recognized as reference measurement procedures (RMPs) by the Joint Committee for Traceability in Laboratory Medicine. These samples and their assigned values serve as the foundation for several aspects of the VDSP. To our knowledge, this is the first time that two RMPs have been used to assign 25(OH)D values to such a large number of serum samples.
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Affiliation(s)
- Karen W Phinney
- National Institute of Standards and Technology, Biomolecular Measurement Division and Chemical Sciences Division, Gaithersburg, MD 20899
| | - Johanna E Camara
- National Institute of Standards and Technology, Biomolecular Measurement Division and Chemical Sciences Division, Gaithersburg, MD 20899
| | - Susan S-C Tai
- National Institute of Standards and Technology, Biomolecular Measurement Division and Chemical Sciences Division, Gaithersburg, MD 20899
| | - Lane C Sander
- National Institute of Standards and Technology, Biomolecular Measurement Division and Chemical Sciences Division, Gaithersburg, MD 20899
| | - Stephen A Wise
- National Institute of Standards and Technology, Biomolecular Measurement Division and Chemical Sciences Division, Gaithersburg, MD 20899
| | - Linde A C De Grande
- Ghent University, Faculty of Pharmaceutical Sciences, Laboratory for Analytical Chemistry, Ghent, Belgium
| | - Linda M Thienpont
- Ghent University, Faculty of Pharmaceutical Sciences, Laboratory for Analytical Chemistry, Ghent, Belgium
| | - Antonio M Possolo
- National Institute of Standards and Technology, Statistical Engineering Division, Gaithersburg, MD 20899
| | - Blaza Toman
- National Institute of Standards and Technology, Statistical Engineering Division, Gaithersburg, MD 20899
| | - Christopher T Sempos
- National Institutes of Health, Office of Dietary Supplements, Bethesda, MD 20892
| | - Joseph M Betz
- National Institutes of Health, Office of Dietary Supplements, Bethesda, MD 20892
| | - Paul M Coates
- National Institutes of Health, Office of Dietary Supplements, Bethesda, MD 20892
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18
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Wise SA, Tai SSC, Burdette CQ, Camara JE, Bedner M, Lippa KA, Nelson MA, Nalin F, Phinney KW, Sander LC, Betz JM, Sempos CT, Coates PM. Role of the National Institute of Standards and Technology (NIST) in Support of the Vitamin D Initiative of the National Institutes of Health, Office of Dietary Supplements. J AOAC Int 2017; 100:1260-1276. [PMID: 28863788 DOI: 10.5740/jaoacint.17-0305] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Since 2005, the National Institute of Standards and Technology (NIST) has collaborated with the National Institutes of Health (NIH), Office of Dietary Supplements (ODS) to improve the quality of measurements related to human nutritional markers of vitamin D status. In support of the NIH-ODS Vitamin D Initiative, including the Vitamin D Standardization Program (VDSP), NIST efforts have focused on (1) development of validated analytical methods, including reference measurement procedures (RMPs); (2) development of Standard Reference Materials (SRMs); (3) value assignment of critical study samples using NIST RMPs; and (4) development and coordination of laboratory measurement QA programs. As a result of this collaboration, NIST has developed RMPs for 25-hydroxyvitamin D2 [25(OH)D2], 25(OH)D3, and 24R,25-dihydroxyvitamin D3 [24R,25(OH)2D3]; disseminated serum-based SRMs with values assigned for 25(OH)D2, 25(OH)D3, 3-epi-25(OH)D3, and 24R,25(OH)2D3; assigned values for critical samples for VDSP studies, including an extensive interlaboratory comparison and reference material commutability study; provided an accuracy basis for the Vitamin D External Quality Assurance Scheme; coordinated the first accuracy-based measurement QA program for the determination of 25(OH)D2, 25(OH)D3, and 3-epi-25(OH)D3 in human serum/plasma; and developed methods and SRMs for the determination of vitamin D and 25(OH)D in food and supplement matrix SRMs. The details of these activities and their benefit and impact to the NIH-ODS Vitamin D Initiative are described.
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Affiliation(s)
- Stephen A Wise
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD 20899
| | - Susan S-C Tai
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD 20899
| | - Carolyn Q Burdette
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD 20899
| | - Johanna E Camara
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD 20899
| | - Mary Bedner
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD 20899
| | - Katrice A Lippa
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD 20899
| | - Michael A Nelson
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD 20899
| | - Federica Nalin
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD 20899
| | - Karen W Phinney
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD 20899
| | - Lane C Sander
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD 20899
| | - Joseph M Betz
- National Institutes of Health, Office of Dietary Supplements, Bethesda, MD 20892
| | - Christopher T Sempos
- National Institutes of Health, Office of Dietary Supplements, Bethesda, MD 20892
| | - Paul M Coates
- National Institutes of Health, Office of Dietary Supplements, Bethesda, MD 20892
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19
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Burdette CQ, Camara JE, Nalin F, Pritchett J, Sander LC, Carter GD, Jones J, Betz JM, Sempos CT, Wise SA. Establishing an Accuracy Basis for the Vitamin D External Quality Assessment Scheme (DEQAS). J AOAC Int 2017; 100:1277-1287. [PMID: 28847346 DOI: 10.5740/jaoacint.17-0306] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Until recently, the Vitamin D External Quality Assessment Scheme (DEQAS) assessed the performance of various assays for the determination of serum total 25-hydroxyvitamin D [25(OH)D] by using a consensus mean based on the all-laboratory trimmed mean (ALTM) of the approximately 1000 participants' results. Since October 2012, the National Institute of Standards and Technology (NIST), as part of the Vitamin D Standardization Program, has participated in DEQAS by analyzing the quarterly serum sample sets using an isotope dilution LC-tandem MS (ID LC-MS/MS) reference measurement procedure to assign an accuracy-based target value for serum total 25(OH)D. NIST has analyzed 90 DEQAS samples (18 exercises × 5 samples/exercise) to assign target values. The NIST-assigned values are compared with the ALTM and the biases assessed for various assays used by the participants, e.g., LC-MS/MS, HPLC, and several ligand-binding assays. The NIST-value assignment process and the results of the analyses of the 90 DEQAS samples are summarized. The absolute mean bias between the NIST-assigned values and the ALTM was 5.6%, with 10% of the samples having biases >10%. Benefits of the accuracy-based target values are presented, including for sample sets with high concentrations of 25(OH)D2 and 3-epi-25(OH)D3.
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Affiliation(s)
- Carolyn Q Burdette
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD 20899
| | - Johanna E Camara
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD 20899
| | - Federica Nalin
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD 20899
| | - Jeanita Pritchett
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD 20899
| | - Lane C Sander
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD 20899
| | - Graham D Carter
- Imperial College Healthcare, Department of Biochemistry, NHS Trust, Charing Cross Hospital, London, United Kingdom
| | - Julia Jones
- Imperial College Healthcare, Department of Biochemistry, NHS Trust, Charing Cross Hospital, London, United Kingdom
| | - Joseph M Betz
- National Institutes of Health, Office of Dietary Supplements, Bethesda, MD 20892
| | - Christopher T Sempos
- National Institutes of Health, Office of Dietary Supplements, Bethesda, MD 20892
| | - Stephen A Wise
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD 20899
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20
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Phinney KW, Sempos CT, Tai SSC, Camara JE, Wise SA, Eckfeldt JH, Hoofnagle AN, Carter GD, Jones J, Myers GL, Durazo-Arvizu R, Miller WG, Bachmann LM, Young IS, Pettit J, Caldwell G, Liu A, Brooks SPJ, Sarafin K, Thamm M, Mensink GBM, Busch M, Rabenberg M, Cashman KD, Kiely M, Galvin K, Zhang JY, Kinsella M, Oh K, Lee SW, Jung CL, Cox L, Goldberg G, Guberg K, Meadows S, Prentice A, Tian L, Brannon PM, Lucas RM, Crump PM, Cavalier E, Merkel J, Betz JM. Baseline Assessment of 25-Hydroxyvitamin D Reference Material and Proficiency Testing/External Quality Assurance Material Commutability: A Vitamin D Standardization Program Study. J AOAC Int 2017; 100:1288-1293. [PMID: 28797319 DOI: 10.5740/jaoacint.17-0291] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The Vitamin D Standardization Program (VDSP) coordinated a study in 2012 to assess the commutability of reference materials and proficiency testing/external quality assurance materials for total 25-hydroxyvitamin D [25(OH)D] in human serum, the primary indicator of vitamin D status. A set of 50 single-donor serum samples as well as 17 reference and proficiency testing/external quality assessment materials were analyzed by participating laboratories that used either immunoassay or LC-MS methods for total 25(OH)D. The commutability test materials included National Institute of Standards and Technology Standard Reference Material 972a Vitamin D Metabolites in Human Serum as well as materials from the College of American Pathologists and the Vitamin D External Quality Assessment Scheme. Study protocols and data analysis procedures were in accordance with Clinical and Laboratory Standards Institute guidelines. The majority of the test materials were found to be commutable with the methods used in this commutability study. These results provide guidance for laboratories needing to choose appropriate reference materials and select proficiency or external quality assessment programs and will serve as a foundation for additional VDSP studies.
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Affiliation(s)
- Karen W Phinney
- National Institute of Standards and Technology, Biomolecular Measurement Division, Gaithersburg, MD
| | | | - Susan S-C Tai
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD
| | - Johanna E Camara
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD
| | - Stephen A Wise
- National Institutes of Health, Office of Dietary Supplements, Bethesda, MD
| | - John H Eckfeldt
- University of Minnesota, Department of Laboratory Medicine and Pathology, Minneapolis, MN
| | - Andrew N Hoofnagle
- University of Washington, Department of Laboratory Medicine, Seattle, WA
| | - Graham D Carter
- Vitamin D External Quality Assessment Scheme, Charing Cross Hospital, London, United Kingdom
| | - Julia Jones
- Vitamin D External Quality Assessment Scheme, Charing Cross Hospital, London, United Kingdom
| | - Gary L Myers
- Joint Committee for Traceability in Laboratory Medicine, Smyrna, GA
| | | | | | | | | | - Juanita Pettit
- Health Surveys, Australian Bureau of Statistics, Canberra, ACT, Australia
| | - Grahame Caldwell
- Douglass Hanly Moir Pathology, Sonic Healthcare, Sydney, NSW, Australia
| | - Andrew Liu
- Douglass Hanly Moir Pathology, Sonic Healthcare, Sydney, NSW, Australia
| | | | - Kurtis Sarafin
- Health Canada, Nutrition Research Division, Ottawa, ON, Canada
| | | | | | | | | | - Kevin D Cashman
- University College Cork, School of Food and Nutritional Sciences, Cork Centre for Vitamin D and Nutrition Research, Cork, Ireland
| | - Mairead Kiely
- University College Cork, School of Food and Nutritional Sciences, Cork Centre for Vitamin D and Nutrition Research, Cork, Ireland
| | - Karen Galvin
- University College Cork, School of Food and Nutritional Sciences, Cork Centre for Vitamin D and Nutrition Research, Cork, Ireland
| | - Joy Y Zhang
- University College Cork, School of Food and Nutritional Sciences, Cork Centre for Vitamin D and Nutrition Research, Cork, Ireland
| | - Michael Kinsella
- University College Cork, School of Food and Nutritional Sciences, Cork Centre for Vitamin D and Nutrition Research, Cork, Ireland
| | - Kyungwon Oh
- Korea Centers for Disease Control and Prevention, Division of Health and Nutrition Survey, Seoul, Korea
| | | | | | - Lorna Cox
- Medical Research Council Elsie Widdowson Laboratory, Cambridge, United Kingdom
| | - Gail Goldberg
- Medical Research Council Elsie Widdowson Laboratory, Cambridge, United Kingdom
| | - Kate Guberg
- Medical Research Council Elsie Widdowson Laboratory, Cambridge, United Kingdom
| | - Sarah Meadows
- Medical Research Council Elsie Widdowson Laboratory, Cambridge, United Kingdom
| | - Ann Prentice
- Medical Research Council Elsie Widdowson Laboratory, Cambridge, United Kingdom
| | - Lu Tian
- Stanford University, Department of Biomedical Data Science, Palo Alto, CA
| | - Patsy M Brannon
- Cornell University, Division of Nutritional Sciences, Ithaca, NY
| | - Robyn M Lucas
- Australian National University, Research School of Population Health, National Centre for Epidemiology and Population Health, Canberra, ACT, Australia
| | - Peter M Crump
- University Computing and Biometry, of Wisconsin-Madison, Madison, WI
| | - Etienne Cavalier
- University of Liege, Centre Hospitalier Universitaire du Sart-Tilman, Liege, Belgium
| | - Joyce Merkel
- Office of Dietary Supplements, National Institutes of Health, Bethesda, MD 20892
| | - Joseph M Betz
- Office of Dietary Supplements, National Institutes of Health, Bethesda, MD 20892
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21
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Sempos CT, Betz JM, Camara JE, Carter GD, Cavalier E, Clarke MW, Dowling KG, Durazo-Arvizu RA, Hoofnagle AN, Liu A, Phinney KW, Sarafin K, Wise SA, Coates PM. General Steps to Standardize the Laboratory Measurement of Serum Total 25-Hydroxyvitamin D. J AOAC Int 2017; 100:1230-1233. [PMID: 28766476 DOI: 10.5740/jaoacint.17-0259] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The Vitamin D Standardization Program (VDSP) has collaborated with numerous groups and agencies to assemble a set of tools, i.e., a reference measurement system, that can be used to establish the traceability of 25-hydroxyvitamin D [25(OH)D] assays to relevant reference measurement procedures and reference materials. This is done with the goal of verifying end-user laboratory performance using precise statistical criteria to determine whether a specific assay is standardized. The purpose of this paper was to outline a set of steps that routine clinical and research laboratories can use to standardize their 25(OH)D assays using these tools. These steps apply to laboratories using commercially developed immunoassay measurement systems as well as in-house assays, usually based on high HPLC or LC tandem MS measurement systems. The steps are (1) initial calibration, (2) initial assessment of accuracy and bias, (3) assessment of total percent CV and mean bias, (4) use of trueness controls, and (5) participation in accuracy-based performance testing and/or external quality assessment schemes. The goal of each laboratory assay is to have a total CV of ≤10% and mean bias of ≤5%. Rigorous and less rigorous but low-cost options for meeting these statistical criteria are provided. Research laboratories who infrequently measure 25(OH)D are advised to repeat steps 1-4 for every measurement cycle. For users of commercial immunoassays who have relatively little control over standardization, we present an option for using trueness controls to develop a master equation that can be used to standardize results to the reference methods.
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Affiliation(s)
| | - Joseph M Betz
- National Institutes of Health, Office of Dietary Supplements, Bethesda, MD
| | - Johanna E Camara
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD
| | - Graham D Carter
- Imperial College Healthcare NHS Trust, London, United Kingdom
| | - Etienne Cavalier
- University of Liège, Centre Hospitalier Universitaire de Liège, Department of Clinical Chemistry, Liège, Belgium
| | - Michael W Clarke
- The University of Western Australia, Centre for Microscopy, Characterisation and Analysis, Perth, WA, 6009 Australia
| | - Kirsten G Dowling
- University College Cork, School of Food and Nutritional Sciences, Cork Centre for Vitamin D and Nutrition Research, Cork, Ireland
| | | | - Andrew N Hoofnagle
- University of Washington, Department of Laboratory Medicine, Seattle, WA
| | - Andy Liu
- Sonic Healthcare, Douglass Hanly Moir Pathology, Sydney, NSW, Australia
| | - Karen W Phinney
- National Institute of Standards and Technology, Biomolecular Measurement Division, Gaithersburg, MD
| | - Kurtis Sarafin
- Health Canada, Nutrition Research Division, Ottawa, ON, Canada
| | - Stephen A Wise
- National Institutes of Health, Office of Dietary Supplements, Bethesda, MD
| | - Paul M Coates
- National Institutes of Health, Office of Dietary Supplements, Bethesda, MD
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22
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Wise SA, Tai SSC, Nelson MA, Burdette CQ, Camara JE, Hoofnagle AN, Laha TJ, Carter GD, Jones J, Williams EL, Barclay ZJ, Jones G, Kaufmann M, Binkley N, Kapoor A, Ziegler T, Cashman KD, Dowling KG, Sempos CT. Interlaboratory Comparison for the Determination of 24,25-Dihydroxyvitamin D₃ in Human Serum Using Liquid Chromatography with Tandem Mass Spectrometry. J AOAC Int 2017; 100:1308-1317. [PMID: 28741469 DOI: 10.5740/jaoacint.17-0183] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Six laboratories associated with the Vitamin D Standardization Program (VDSP) participated in an interlaboratory comparison of LC with tandem MS (MS/MS) methods for the determination of 24,25-dihydroxyvitamin D3 [24,25(OH)2D3] in human serum. The laboratories analyzed two different serum-based Standard Reference Materials (SRMs) intended for use in the determination of 25-hydroxyvitamin D and 30 samples from the Vitamin D External Quality Assessment Scheme (DEQAS). All laboratory methods for 24,25(OH)2D3 were based on isotope dilution LC-MS/MS; three of the methods used derivatization of the vitamin D metabolites before LC-MS/MS. Laboratory results were compared to the National Institute of Standards and Technology (NIST) results, which were obtained using their newly developed candidate reference measurement procedure for 24,25(OH)2D3. Laboratory results for the SRM samples varied in comparability to the NIST results, with one laboratory in excellent agreement (-1.6% mean bias), three laboratories at 10-15% mean bias, and the remaining laboratory at 36% mean bias. For the 30 DEQAS samples, the mean bias for the five laboratories ranged from 6 to 15%; however, the SD of the bias ranged from 8 to 29%. As a result of this intercomparison study, one laboratory discovered and corrected a method calculation error and another laboratory modified and improved their LC-MS/MS method.
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Affiliation(s)
- Stephen A Wise
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD 20899
| | - Susan S-C Tai
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD 20899
| | - Michael A Nelson
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD 20899
| | - Carolyn Q Burdette
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD 20899
| | - Johanna E Camara
- National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD 20899
| | - Andrew N Hoofnagle
- University of Washington, Department of Laboratory Medicine, Seattle, WA 98195-7110
| | - Thomas J Laha
- University of Washington, Department of Laboratory Medicine, Seattle, WA 98195-7110
| | - Graham D Carter
- Imperial College Healthcare National Health Service Trust, Charing Cross Hospital, Department of Biochemistry, London, United Kingdom
| | - Julia Jones
- Imperial College Healthcare National Health Service Trust, Charing Cross Hospital, Department of Biochemistry, London, United Kingdom
| | - Emma L Williams
- Imperial College Healthcare National Health Service Trust, Charing Cross Hospital, Department of Biochemistry, London, United Kingdom
| | - Zoe J Barclay
- Imperial College Healthcare National Health Service Trust, Charing Cross Hospital, Department of Biochemistry, London, United Kingdom
| | | | | | - Neil Binkley
- University of Wisconsin-Madison, Madison, WI 53706
| | - Amita Kapoor
- University of Wisconsin-Madison, Madison, WI 53706
| | - Toni Ziegler
- University of Wisconsin-Madison, Madison, WI 53706
| | - Kevin D Cashman
- University College Cork, School of Food and Nutritional Sciences, Cork Centre for Vitamin D and Nutrition Research, Cork, Ireland
| | - Kirsten G Dowling
- University College Cork, School of Food and Nutritional Sciences, Cork Centre for Vitamin D and Nutrition Research, Cork, Ireland
| | - Christopher T Sempos
- National Institutes of Health, Office of Dietary Supplements, Bethesda, MD 20892
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Phinney KW, Tai SSC, Bedner M, Camara JE, Chia RR, Sander LC, Sharpless KE, Wise SA, Yen JH, Schleicher RL, Chaudhary-Webb M, Maw KL, Rahmani Y, Betz JM, Merkel J, Sempos CT, Coates PM, Durazo-Arvizu RA, Sarafin K, Brooks SP. Development of an Improved Standard Reference Material for Vitamin D Metabolites in Human Serum. Anal Chem 2017; 89:4907-4913. [PMID: 28375002 PMCID: PMC5575745 DOI: 10.1021/acs.analchem.6b05168] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The National Institute of Standards and Technology (NIST) has developed Standard Reference Material (SRM) 972a Vitamin D Metabolites in Frozen Human Serum as a replacement for SRM 972, which is no longer available. SRM 972a was developed in collaboration with the National Institutes of Health's Office of Dietary Supplements. In contrast to the previous reference material, three of the four levels of SRM 972a are composed of unmodified human serum. This SRM has certified and reference values for the following 25-hydroxyvitamin D [25(OH)D] species: 25(OH)D2, 25(OH)D3, and 3-epi-25(OH)D3. The value assignment and certification process included three isotope-dilution mass spectrometry approaches, with measurements performed at NIST and at the Centers for Disease Control and Prevention (CDC). The value assignment methods employed have been modified from those utilized for the previous SRM, and all three approaches now incorporate chromatographic resolution of the stereoisomers, 25(OH)D3 and 3-epi-25(OH)D3.
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Affiliation(s)
- Karen W. Phinney
- Biomolecular Measurement Division and Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - Susan S.-C. Tai
- Biomolecular Measurement Division and Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - Mary Bedner
- Biomolecular Measurement Division and Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - Johanna E. Camara
- Biomolecular Measurement Division and Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - Rosalind R.C. Chia
- Biomolecular Measurement Division and Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - Lane C. Sander
- Biomolecular Measurement Division and Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - Katherine E. Sharpless
- Biomolecular Measurement Division and Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - Stephen A. Wise
- Biomolecular Measurement Division and Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - James H. Yen
- Statistical Engineering Division, National Institute of Standards and Technology Gaithersburg, MD 20899
| | - Rosemary L. Schleicher
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341
| | - Madhulika Chaudhary-Webb
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341
| | - Khin L. Maw
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341
| | - Yasamin Rahmani
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341
| | - Joseph M. Betz
- Office of Dietary Supplements, National Institutes of Health, Bethesda, MD 20892
| | - Joyce Merkel
- Office of Dietary Supplements, National Institutes of Health, Bethesda, MD 20892
| | | | - Paul M. Coates
- Office of Dietary Supplements, National Institutes of Health, Bethesda, MD 20892
| | - Ramón A. Durazo-Arvizu
- Department of Public Health Sciences, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153
| | - Kurtis Sarafin
- Bureau of Nutritional Sciences, Health Canada, Ottawa, Ontario, Canada K1A 0K9
| | - Stephen P.J. Brooks
- Bureau of Nutritional Sciences, Health Canada, Ottawa, Ontario, Canada K1A 0K9
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Sarafin K, Durazo-Arvizu R, Tian L, Phinney KW, Tai S, Camara JE, Merkel J, Green E, Sempos CT, Brooks SPJ. Standardizing 25-hydroxyvitamin D values from the Canadian Health Measures Survey. Am J Clin Nutr 2015; 102:1044-50. [PMID: 26423385 PMCID: PMC4625585 DOI: 10.3945/ajcn.114.103689] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 08/28/2015] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The Canadian Health Measures Survey (CHMS) is an ongoing cross-sectional national survey that includes a measure of 25-hydroxyvitamin D [25(OH)D] by immunoassay. For cycles 1 and 2, the collection period occurred approximately every 2 y, with a new sample of ∼5600 individuals. OBJECTIVE The goal was to standardize the original 25(OH)D CHMS values in cycles 1 and 2 to the internationally recognized reference measurement procedures (RMPs) developed by the US National Institute for Standards and Technology (NIST) and Ghent University, Belgium. DESIGN Standardization was accomplished by using a 2-step procedure. First, serum samples corresponding to the original plasma samples were remeasured by using the currently available immunoassay method. Second, 50 serum samples with known 25(OH)D values assigned by the NIST and Ghent reference method laboratories were measured by using the currently available immunoassay method. The mathematical models for each step-i.e., 1) YCurrent = XOriginal and 2) YNIST-Ghent = XCurrent -were estimated by using Deming regression, and the 2 models were solved to obtain a single equation for converting the "original" values to NIST-Ghent RMP values. RESULTS After standardization (cycles 1 and 2 combined), the percentage of Canadians with 25(OH)D values <40 nmol/L increased from 16.4% (original) to 19.4% (standardized), and values <50 nmol/L increased from 29.0% (original) to 36.8% (standardized). The 25(OH)D standardized distributions (cycles 1 and 2 analyzed separately) were similar across age and sex groups; slightly higher values were associated with cycle 2 in the young and old. This finding contrasts with the original data, which indicated that cycle 2 values were lower for all age groups. CONCLUSION The shifts in 25(OH)D distribution brought about by standardization indicate its importance in drawing correct conclusions about potential population deficiencies and insufficiencies and in permitting the comparison of distributions between national surveys.
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Affiliation(s)
- Kurtis Sarafin
- Bureau of Nutritional Sciences, Health Canada, Ottawa, Canada
| | - Ramón Durazo-Arvizu
- Department of Public Health Sciences, Loyola University of Chicago Stritch School of Medicine, Chicago, IL
| | - Lu Tian
- Department of Health Research and Policy, Stanford University School of Medicine, Palo Alto, CA
| | | | - Susan Tai
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD
| | - Johanna E Camara
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD
| | - Joyce Merkel
- NIH, Office of Dietary Supplements, Bethesda, MD; and
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Phinney KW, Ballihaut G, Bedner M, Benford BS, Camara JE, Christopher SJ, Davis WC, Dodder NG, Eppe G, Lang BE, Long SE, Lowenthal MS, McGaw EA, Murphy KE, Nelson BC, Prendergast JL, Reiner JL, Rimmer CA, Sander LC, Schantz MM, Sharpless KE, Sniegoski LT, Tai SSC, Thomas JB, Vetter TW, Welch MJ, Wise SA, Wood LJ, Guthrie WF, Hagwood CR, Leigh SD, Yen JH, Zhang NF, Chaudhary-Webb M, Chen H, Fazili Z, LaVoie DJ, McCoy LF, Momin SS, Paladugula N, Pendergrast EC, Pfeiffer CM, Powers CD, Rabinowitz D, Rybak ME, Schleicher RL, Toombs BMH, Xu M, Zhang M, Castle AL. Development of a Standard Reference Material for metabolomics research. Anal Chem 2013; 85:11732-8. [PMID: 24187941 PMCID: PMC4823010 DOI: 10.1021/ac402689t] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The National Institute of Standards and Technology (NIST), in collaboration with the National Institutes of Health (NIH), has developed a Standard Reference Material (SRM) to support technology development in metabolomics research. SRM 1950 Metabolites in Human Plasma is intended to have metabolite concentrations that are representative of those found in adult human plasma. The plasma used in the preparation of SRM 1950 was collected from both male and female donors, and donor ethnicity targets were selected based upon the ethnic makeup of the U.S. population. Metabolomics research is diverse in terms of both instrumentation and scientific goals. This SRM was designed to apply broadly to the field, not toward specific applications. Therefore, concentrations of approximately 100 analytes, including amino acids, fatty acids, trace elements, vitamins, hormones, selenoproteins, clinical markers, and perfluorinated compounds (PFCs), were determined. Value assignment measurements were performed by NIST and the Centers for Disease Control and Prevention (CDC). SRM 1950 is the first reference material developed specifically for metabolomics research.
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Affiliation(s)
- Karen W. Phinney
- Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Guillaume Ballihaut
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Mary Bedner
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Brandi S. Benford
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Johanna E. Camara
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Steven J. Christopher
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - W. Clay Davis
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Nathan G. Dodder
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Gauthier Eppe
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Brian E. Lang
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Stephen E. Long
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Mark S. Lowenthal
- Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Elizabeth A. McGaw
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Karen E. Murphy
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Bryant C. Nelson
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Jocelyn L. Prendergast
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Jessica L. Reiner
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Catherine A. Rimmer
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Lane C. Sander
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Michele M. Schantz
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Katherine E. Sharpless
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Lorna T. Sniegoski
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Susan S.-C. Tai
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Jeanice B. Thomas
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Thomas W. Vetter
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Michael J. Welch
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Stephen A. Wise
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Laura J. Wood
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - William F. Guthrie
- Statistical Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Charles R. Hagwood
- Statistical Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Stefan D. Leigh
- Statistical Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - James H. Yen
- Statistical Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Nien-Fan Zhang
- Statistical Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Madhu Chaudhary-Webb
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, United States
| | - Huiping Chen
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, United States
| | - Zia Fazili
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, United States
| | - Donna J. LaVoie
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, United States
| | - Leslie F. McCoy
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, United States
| | - Shahzad S. Momin
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, United States
| | - Neelima Paladugula
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, United States
| | - Elizabeth C. Pendergrast
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, United States
| | - Christine M. Pfeiffer
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, United States
| | - Carissa D. Powers
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, United States
| | - Daniel Rabinowitz
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, United States
| | - Michael E. Rybak
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, United States
| | - Rosemary L. Schleicher
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, United States
| | - Bridgette M. H. Toombs
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, United States
| | - Mary Xu
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, United States
| | - Mindy Zhang
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, United States
| | - Arthur L. Castle
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
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Camara JE, Lowenthal MS, Phinney KW. Determination of fortified and endogenous folates in food-based Standard Reference Materials by liquid chromatography-tandem mass spectrometry. Anal Bioanal Chem 2013; 405:4561-8. [PMID: 23354578 DOI: 10.1007/s00216-013-6733-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 12/21/2012] [Accepted: 01/10/2013] [Indexed: 11/25/2022]
Abstract
The National Institute of Standards and Technology (NIST) is developing a wide variety of Standard Reference Materials (SRMs) to support measurements of vitamins and other nutrients in foods. Previously, NIST has provided SRMs with values assigned for the folate vitamer, folic acid (pteroylglutamic acid), which is fortified in several foods due to its role in prevention of neural tube defects. In order to expand the number of food-based SRMs with values assigned for folic acid, as well as additional endogenous folates, NIST has developed methods that include trienzyme digestion and isotope-dilution liquid chromatography-tandem mass spectrometric (LC-MS/MS) analysis. Sample preparation was optimized for each individual food type, but all samples were analyzed under the same LC-MS/MS conditions. The application of these methods resulted in folic acid values for SRM 1849a Infant/Adult Nutritional Formula and SRM 3233 Fortified Breakfast Cereal of (2.33 ± 0.06) μg/g and (16.0 ± 0.7) μg/g, respectively. In addition, the endogenous folate vitamer 5-methlytetrahydrofolate (5-MTHF) was detected and quantified in SRM 1849a Infant/Adult Nutritional Formula, candidate SRM 1549a Whole Milk Powder, and candidate SRM 1845a Whole Egg Powder, resulting in values of (0.0839 ± 0.0071) μg/g, (0.211 ± 0.014) μg/g, and (0.838 ± 0.044) μg/g, respectively. SRM 1849a Infant/Adult Nutritional Formula is the first food-based NIST SRM to possess a reference value for 5-MTHF and the first certified reference material to have an assigned 5-MTHF value based on LC-MS/MS. The values obtained for folic acid and 5-MTHF by LC-MS/MS will be incorporated into the final value assignments for all these food-based SRMs.
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Affiliation(s)
- Johanna E Camara
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
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27
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Kilpatrick EL, Liao WL, Camara JE, Turko IV, Bunk DM. Expression and characterization of 15N-labeled human C-reactive protein in Escherichia coli and Pichia pastoris for use in isotope-dilution mass spectrometry. Protein Expr Purif 2012; 85:94-9. [DOI: 10.1016/j.pep.2012.06.019] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 05/31/2012] [Accepted: 06/28/2012] [Indexed: 10/28/2022]
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28
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Camara JE, Lippa KA, Duewer DL, Gasca-Aragon H, Toman B. An international assessment of the metrological equivalence of higher-order measurement services for creatinine in serum. Anal Bioanal Chem 2012; 403:527-35. [DOI: 10.1007/s00216-012-5869-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Revised: 02/10/2012] [Accepted: 02/12/2012] [Indexed: 10/28/2022]
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Camara JE, Hays FA. Discrimination between wild-type and ampicillin-resistant Escherichia coli by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Anal Bioanal Chem 2007; 389:1633-8. [PMID: 17849103 DOI: 10.1007/s00216-007-1558-7] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Revised: 08/08/2007] [Accepted: 08/15/2007] [Indexed: 11/26/2022]
Abstract
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was optimized to discriminate between wild-type and ampicillin-resistant Escherichia coli. Only ampicillin-resistant E. coli displayed an m/z approximately 29,000 peak, which was confirmed as beta-lactamase by in-gel digestion followed by peptide mass fingerprinting. Rapid MALDI-TOF MS detection of antibiotic-resistance could fulfill an important clinical need, providing critical phenotypic information beyond genus-species identification.
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Affiliation(s)
- Johanna E Camara
- Analytical Chemistry Division, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA.
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30
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Camara JE, Satterfield MB, Nelson BC. Quantitative determination of disaccharide content in digested unfragmented heparin and low molecular weight heparin by direct-infusion electrospray mass spectrometry. J Pharm Biomed Anal 2007; 43:1706-14. [PMID: 17275239 DOI: 10.1016/j.jpba.2007.01.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Revised: 12/28/2006] [Accepted: 01/06/2007] [Indexed: 11/19/2022]
Abstract
Heparins and low molecular weight heparins (LMWHs) are heterogeneous glycosaminoglycans derived from natural sources that are prescribed as anticoagulants. In this work, a direct-infusion electrospray ionization mass spectrometry (ESI-MS) method was applied to the quantitative analysis of known disaccharides in various native heparins and LMWHs after digestion with heparinase enzymes. Disaccharide deltaUA2S-->GlcNS6S was found to compose the majority of all samples analyzed (81-88%). The values were significantly higher than those reported by previously published methods. The disaccharide isomer pair deltaUA-->GlcNS6S/deltaUA2S-->GlcNS was also detected in all samples at lower levels (11-19%). While digestion with heparinases I and II revealed a limited number of disaccharides, the addition of heparinase III to digests led to the detection of disaccharide deltaUA2S-->GlcNAc6S in native porcine heparin. This result indicated the importance of utilizing all three heparinases to gain maximum information when analyzing heparin and LMWH digests. This method displayed good between-day (4-6%) and between-digest (1-2%) reproducibility in separate experiments. To determine if the digestion matrix was suppressing the signal of low-abundance disaccharides, several disaccharides were exogenously added at low levels (1-10 pmol/mg) to a quenched digest reaction. Analysis revealed that low level disaccharides were detectable in this matrix above the limits of detection (0.1-0.2 pmol/mg) and quantitation (0.2-0.7 pmol/mg). While this method was unable to distinguish between disaccharide isomers, it utilized simple mass spectrometry instrumentation to provide useful quantitative data for characterizing preparations of native heparin and LMWH, which could be used to compare various marketed preparations of these popular anticoagulants.
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Affiliation(s)
- Johanna E Camara
- Analytical Chemistry Division, National Institute of Standards and Technology, 100 Bureau Drive, Stop 8392, Gaithersburg, MD 20899, United States.
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31
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Gon S, Camara JE, Klungsøyr HK, Crooke E, Skarstad K, Beckwith J. A novel regulatory mechanism couples deoxyribonucleotide synthesis and DNA replication in Escherichia coli. EMBO J 2006; 25:1137-47. [PMID: 16482221 PMCID: PMC1409723 DOI: 10.1038/sj.emboj.7600990] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2005] [Accepted: 01/17/2006] [Indexed: 11/08/2022] Open
Abstract
We present evidence for a complex regulatory interplay between the initiation of DNA replication and deoxyribonucleotide synthesis. In Escherichia coli, the ATP-bound DnaA protein initiates chromosomal replication. Upon loading of the beta-clamp subunit (DnaN) of the replicase, DnaA is inactivated as its intrinsic ATPase activity is stimulated by the protein Hda. The beta-subunit acts as a matchmaker between Hda and DnaA. Chain elongation of DNA requires a sufficient supply of deoxyribonucleotides (dNTPs), which are produced by ribonucleotide reductase (RNR). We present evidence suggesting that the molecular switch from ATP-DnaA to ADP-DnaA is a critical step coordinating DNA replication with increased deoxyribonucleotide synthesis. Characterization of dnaA and dnaN mutations that result in a constitutively high expression of RNR reveal this mechanism. We propose that the nucleotide bound state of DnaA regulates the transcription of the genes encoding ribonucleotide reductase (nrdAB). Accordingly, the conversion of ATP-DnaA to ADP-DnaA after initiation and loading of the beta-subunit DnaN would allow increased nrdAB expression, and consequently, coordinated RNR synthesis and DNA replication during the cell cycle.
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Affiliation(s)
- Stéphanie Gon
- Department of Microbiology, Harvard Medical School, Boston, MA, USA.
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32
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Camara JE, Breier AM, Brendler T, Austin S, Cozzarelli NR, Crooke E. Hda inactivation of DnaA is the predominant mechanism preventing hyperinitiation of Escherichia coli DNA replication. EMBO Rep 2006; 6:736-41. [PMID: 16041320 PMCID: PMC1369143 DOI: 10.1038/sj.embor.7400467] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2005] [Revised: 05/30/2005] [Accepted: 06/02/2005] [Indexed: 11/09/2022] Open
Abstract
Initiation of DNA replication from the Escherichia coli chromosomal origin is highly regulated, assuring that replication occurs precisely once per cell cycle. Three mechanisms for regulation of replication initiation have been proposed: titration of free DnaA initiator protein by the datA locus, sequestration of newly replicated origins by SeqA protein and regulatory inactivation of DnaA (RIDA), in which active ATP-DnaA is converted to the inactive ADP-bound form. DNA microarray analyses showed that the level of initiation in rapidly growing cells that lack datA was indistinguishable from that in wild-type cells, and that the absence of SeqA protein caused only a modest increase in initiation, in agreement with flow-cytometry data. In contrast, cells lacking Hda overinitiated replication twofold, implicating RIDA as the predominant mechanism preventing extra initiation events in a cell cycle.
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Affiliation(s)
- Johanna E Camara
- Department of Biochemistry and Molecular Biology, Georgetown University Medical Center, 3900 Reservoir Road NW, Washington, District of Columbia 20007, USA
| | - Adam M Breier
- Molecular and Cell Biology, University of California, Berkeley, 16 Barker Hall, Berkeley, California 94720, USA
| | - Therese Brendler
- NCI-DBS, Frederick Cancer Research and Development Center, Box B, Building 539/223, Frederick, Maryland 21702, USA
| | - Stuart Austin
- NCI-DBS, Frederick Cancer Research and Development Center, Box B, Building 539/223, Frederick, Maryland 21702, USA
| | - Nicholas R Cozzarelli
- Molecular and Cell Biology, University of California, Berkeley, 16 Barker Hall, Berkeley, California 94720, USA
| | - Elliott Crooke
- Department of Biochemistry and Molecular Biology, Georgetown University Medical Center, 3900 Reservoir Road NW, Washington, District of Columbia 20007, USA
- Tel: +1 202 687 1644; Fax: +1 202 687 7186; E-mail:
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Ryan VT, Grimwade JE, Camara JE, Crooke E, Leonard AC. Escherichia coli prereplication complex assembly is regulated by dynamic interplay among Fis, IHF and DnaA. Mol Microbiol 2004; 51:1347-59. [PMID: 14982629 DOI: 10.1046/j.1365-2958.2003.03906.x] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Initiator DnaA and DNA bending proteins, Fis and IHF, comprise prereplication complexes (pre-RC) that unwind the Escherichia coli chromosome's origin of replication, oriC. Loss of either Fis or IHF perturbs synchronous initiation from oriC copies in rapidly growing E. coli. Based on dimethylsulphate (DMS) footprinting of purified proteins, we observed a dynamic interplay among Fis, IHF and DnaA on supercoiled oriC templates. Low levels of Fis inhibited oriC unwinding by blocking both IHF and DnaA binding to low affinity sites. As the concentration of DnaA was increased, Fis repression was relieved and IHF rapidly redistributed DnaA to all unfilled binding sites on oriC. This behaviour in vitro is analogous to observed assembly of pre-RC in synchronized E. coli. We propose that as new DnaA is synthesized in E. coli, opposing activities of Fis and IHF ensure an abrupt transition from a repressed complex with unfilled weak affinity DnaA binding sites to a completely loaded unwound complex, increasing both the precision of DNA replication timing and initiation synchrony.
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Affiliation(s)
- Valorie T Ryan
- Department of Biological Sciences, Florida Institute of Technology, Melbourne, Florida 32901-6795, USA
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