1
|
Wielders JPM, Porpiglia NM, Schellenberg F, Deenmamode J, Delanghe J, Anton RF, Bortolotti F, Siebelder C, Tagliaro F, Weykamp C, Helander A. Recommendations on the measurement and use of the alcohol consumption biomarker CDT. A position paper from the IFCC Working Group on CDT standardisation. Clin Chim Acta 2024; 555:117800. [PMID: 38309557 DOI: 10.1016/j.cca.2024.117800] [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: 09/29/2023] [Revised: 01/10/2024] [Accepted: 01/22/2024] [Indexed: 02/05/2024]
Abstract
BACKGROUND Carbohydrate deficient transferrin (CDT) is a biomarker for excessive alcohol consumption utilized in clinical and forensic medicine and workplace testing. Previously, many different analytical methods for CDT were used and the measurand varied considerably, making direct comparison of test results difficult. To end this confusion, the IFCC established a working group on CDT standardisation (WG-CDT) which completed its tasks in 2017. METHODS This IFCC position paper by the WG-CDT summarizes state of the art information about the measurand and the analytical methods and gives concise recommendations for its utilization. RESULTS The results achieved by the CDT standardisation process led to accuracy improvements in national external quality assessment schemes over the years. A brief review of ROC based comparison studies with the traditional biomarkers (GGT, MCV, ALT and AST) discusses the bias resulting from inadequate study populations. In large groups of the general population the superior diagnostic performance of CDT is confirmed. CONCLUSION The relationship between alcohol intake versus resulting CDT is discussed as well as the cutoff and measurement uncertainty. Concerning the application in practice, potential pitfalls are considered and recommendations handling both analytical and preanalytical caveats are given. Finally, some examples of serious misunderstandings in publications about CDT are addressed.
Collapse
Affiliation(s)
- J P M Wielders
- Joseph Peter Marie Wielders, Amersfoort, the Netherlands.
| | - N M Porpiglia
- Nadia Maria Porpiglia, Department of Diagnostics and Public Health, Unit of Forensic Medicine, University of Verona, Verona, Italy.
| | | | | | - J Delanghe
- Joris Delanghe, Department of Laboratory Medicine, Ghent University Hospital, Ghent, Belgium
| | - R F Anton
- Raymond Francis Anton, Medical University of South Carolina, Charleston, SC, USA
| | - F Bortolotti
- Federica Bortolotti, Department of Diagnostics and Public Health, Unit of Forensic Medicine, University of Verona, Verona, Italy
| | - C Siebelder
- Carla Siebelder, MCA Laboratory, Queen Beatrix Hospital, Winterswijk, the Netherlands
| | - F Tagliaro
- Franco Tagliaro, Department of Diagnostics and Public Health, Unit of Forensic Medicine, University of Verona, Verona, Italy
| | - C Weykamp
- Cas Weykamp, MCA Laboratory, Queen Beatrix Hospital, Winterswijk, the Netherlands
| | - A Helander
- Anders Helander, Karolinska Institutet, Karolinska University Laboratory, Stockholm, Sweden
| |
Collapse
|
2
|
Weykamp C, Siebelder C, Lenters E, Slingerland R, English E. The risk of clinical misinterpretation of HbA1c: Modelling the impact of biological variation and analytical performance on HbA1c used for diagnosis and monitoring of diabetes. Clin Chim Acta 2023; 548:117495. [PMID: 37479013 DOI: 10.1016/j.cca.2023.117495] [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: 07/14/2023] [Accepted: 07/18/2023] [Indexed: 07/23/2023]
Abstract
BACKGROUND The validity of clinical interpretation of HbA1c depends on the analytical performance of the method and the biological variation of HbA1c in patients. The contribution of non-glucose related factors to the biological variation of HbA1c (NGBVA1c) is not known. This paper explores the cumulative impact of analytical errors and NGBVA1c on the risk of misinterpretation. METHODS A model has been developed to predict the risk of misinterpretation of HbA1c for diagnosis and monitoring with variables for analytical performance and levels of NGBVA1c. RESULTS The model results in probabilities of misinterpretation for a given HbA1c. EXAMPLE for an HbA1c 43 mmol/mol (6.1%), bias 1 mmol/mol (0.09%), CV 3% (2%) used for diagnosis, the probabilities of misinterpretation range from 1 to 19% depending on the contribution of NGBVA1c to the biological variation of HbA1c. CONCLUSIONS In addition to analytical bias and imprecision, NGBVA1c contributes to the risk of misinterpretation, but the relative impact is different per clinical application of HbA1c. For monitoring, imprecision is the predominating factor, for diagnosis both biological variation and analytical bias. Given the increasing use of HbA1c for diagnosis, increase of knowledge on NGBVA1c, decrease of analytical bias, and awareness of the risk of misinterpretation are required.
Collapse
Affiliation(s)
- Cas Weykamp
- Streekziekenhuis Koningin Beatrix, Department of Clinical Chemistry, Beatrixpark 1, 7101BN Winterswijk, the Netherlands; European Reference Laboratory for Glycohemoglobin, location Winterswijk, Beatrixpark 1, 7101BN Winterswijk, the Netherlands.
| | - Carla Siebelder
- Streekziekenhuis Koningin Beatrix, Department of Clinical Chemistry, Beatrixpark 1, 7101BN Winterswijk, the Netherlands; European Reference Laboratory for Glycohemoglobin, location Winterswijk, Beatrixpark 1, 7101BN Winterswijk, the Netherlands
| | - Erna Lenters
- Isala, Department of Clinical Chemistry, Dr Van Heesweg 2, 8025AB Zwolle, the Netherlands; European Reference Laboratory for Glycohemoglobin, location Zwolle, Dr Van Heesweg 2, 8025AB Zwolle, the Netherlands
| | - Robbert Slingerland
- Isala, Department of Clinical Chemistry, Dr Van Heesweg 2, 8025AB Zwolle, the Netherlands; European Reference Laboratory for Glycohemoglobin, location Zwolle, Dr Van Heesweg 2, 8025AB Zwolle, the Netherlands
| | - Emma English
- Faculty of Medicine and Health, Queens' Building, University of East Anglia, Norwich NR4 7TJ, UK
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
van der Hagen EAE, Weykamp C, Sandberg S, Stavelin AV, MacKenzie F, Miller WG. Feasibility for aggregation of commutable external quality assessment results to evaluate metrological traceability and agreement among results. Clin Chem Lab Med 2020; 59:117-125. [PMID: 32759402 DOI: 10.1515/cclm-2020-0736] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [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: 05/15/2020] [Accepted: 07/22/2020] [Indexed: 11/15/2022]
Abstract
Objectives External quality assessment (EQA) with commutable samples is used for assessing agreement of results for patients' samples. We investigated the feasibility to aggregate results from four different EQA schemes to determine the bias between different measurement procedures and a reference target value. Methods We aggregated EQA results for creatinine from programs that used commutable EQA material by calculating the relative difference between individual participant results and the reference target value for each sample. The means and standard errors of the means were calculated for the relative differences. Results were partitioned by methods, manufacturers and instrument platforms to evaluate the biases for the measurement procedures. Results Data aggregated for enzymatic methods had biases that varied from -8.2 to 3.8% among seven instrument platforms for creatinine at normal concentrations (61-85 μmol/L). EQA schemes differed in the evidence provided about the commutability of their samples, and in the amount of detail collected from participants regarding the measurement procedures which limited the ability to sub-divide aggregated data by instrument platforms and models. Conclusions EQA data could be aggregated from four different programs using different commutable samples to determine bias among different measurement procedures. Criteria for commutability for EQA samples as well as standardization of reporting the measurement methods, reagents, instrument platforms and models used by participants are needed to improve the ability to aggregate the results for optimal assessment of performance of measurement procedures. Aggregating data from a larger number of EQA schemes is feasible to assess trueness on a global scale.
Collapse
Affiliation(s)
- Eline A E van der Hagen
- Dutch Foundation for Quality Assessment in Medical Laboratories (SKML), Nijmegen, The Netherlands.,Department of Clinical Chemistry, Queen Beatrix Hospital, Winterswijk, The Netherlands
| | - Cas Weykamp
- Dutch Foundation for Quality Assessment in Medical Laboratories (SKML), Nijmegen, The Netherlands.,Department of Clinical Chemistry, Queen Beatrix Hospital, Winterswijk, The Netherlands
| | - Sverre Sandberg
- The Norwegian Organisation for Quality Improvement of Laboratory Examinations (Noklus), Haraldsplass Deaconess Hospital, Noklus, Bergen, Norway
| | - Anne V Stavelin
- The Norwegian Organisation for Quality Improvement of Laboratory Examinations (Noklus), Haraldsplass Deaconess Hospital, Noklus, Bergen, Norway
| | - 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, USA
| |
Collapse
|
5
|
Arnaud J, Patriarca M, Fofou-Caillierez BM, González-Estecha M, Gómez MG, De Graaf I, Patriarca V, Ropert-Bouchet M, Schröer-Janssen L, Siebelder C, Te Winkel M, Ventura Alemany M, Weykamp C. External quality assessment schemes for inorganic elements in the clinical laboratory: Lessons from the OELM scheme. J Trace Elem Med Biol 2020; 59:126414. [PMID: 31810809 DOI: 10.1016/j.jtemb.2019.126414] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 09/05/2019] [Accepted: 10/03/2019] [Indexed: 12/01/2022]
Abstract
Measurements of inorganic elements in clinical laboratories produce results used for the diagnosis, the treatment and the monitoring of deficiencies or overloads. The main objective of External Quality Assessment Schemes is to verify, on a regular frequency, that clinical laboratory results correspond to the quality requirement for patient care. Therefore, External Quality Assessment Schemes represent an essential component of a laboratory's quality management system. However, External Quality Assessment Schemes within the same analytical field remain heterogeneous for different reasons such as samples, determination of assigned value, acceptable limits, content of the reports. The aim of this review was to describe and illustrate some major critical aspects of External Quality Assessment Schemes based on Occupational and Environmental Laboratory Medicine external quality assessment scheme experience.
Collapse
Affiliation(s)
- Josiane Arnaud
- Unité de biochimie hormonale et nutritionnelle, Institut de Biologie et Pathologie, CHU Grenoble Alpes, CS 10217, 38043, Grenoble cedex 9, France.
| | - Marina Patriarca
- Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Roma (I), Italy.
| | - Béatrice Ma'atem Fofou-Caillierez
- Biochimie et Biologie Moléculaire, Nutrition et Métabolisme, Hôpital Brabois, CHRU Nancy, 5 rue du Morvan, 54511 Vandoeuvre-les-Nancy Cedex, France.
| | - Montserrat González-Estecha
- Servicio de Análisis Clínicos, IML. IdISSC, Hospital Clínico San Carlos, Calle Profesor Martín Lagos 1, 28040, Madrid, Spain.
| | - MªCarmen González Gómez
- Programas de Garantía Externa de la Calidad para Laboratorios Clínicos, Sociedad Española de Medicina de Laboratorio (SEQC-ML), Padilla 323, despacho 68, 08025 Barcelona, Spain.
| | - Irene De Graaf
- MCA Laboratorium, Streekziekenhuis Koningin Beatrix, Beatrixpark 1, Postbus 9005, 7100 GG Winterswijk, the Netherlands.
| | - Valeria Patriarca
- Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Roma (I), Italy.
| | - Martine Ropert-Bouchet
- Laboratoire de Biochimie Toxicologie, CHU de Rennes, 2 rue Henri Le Guilloux, 35033 Rennes cedex 9, France.
| | - Liesbeth Schröer-Janssen
- MCA Laboratorium, Streekziekenhuis Koningin Beatrix, Beatrixpark 1, Postbus 9005, 7100 GG Winterswijk, the Netherlands.
| | - Carla Siebelder
- MCA Laboratorium, Streekziekenhuis Koningin Beatrix, Beatrixpark 1, Postbus 9005, 7100 GG Winterswijk, the Netherlands.
| | - Marieke Te Winkel
- MCA Laboratorium, Streekziekenhuis Koningin Beatrix, Beatrixpark 1, Postbus 9005, 7100 GG Winterswijk, the Netherlands.
| | - Montserrat Ventura Alemany
- Programas de Garantía Externa de la Calidad para Laboratorios Clínicos, Sociedad Española de Medicina de Laboratorio (SEQC-ML), Padilla 323, despacho 68, 08025 Barcelona, Spain.
| | - Cas Weykamp
- MCA Laboratorium, Streekziekenhuis Koningin Beatrix, Beatrixpark 1, Postbus 9005, 7100 GG Winterswijk, the Netherlands.
| |
Collapse
|
6
|
English E, Weykamp C, Ji L, Siebelder C, Shan Z, Wang Y, Li H, Garry John W. The global impact of the International Federation of Clinical Chemistry and Laboratory Medicine, Education and Management Division: engaging stakeholders and assessing HbA1c quality in a multicentre study across China. Clin Chem Lab Med 2019; 57:288-295. [PMID: 30044761 DOI: 10.1515/cclm-2018-0434] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [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: 04/24/2018] [Accepted: 06/12/2018] [Indexed: 11/15/2022]
Abstract
Background Diabetes mellitus is a major global issue and high quality testing is essential for the diagnosis and treatment of the disease. The IFCC Committee for the Education in the Utility of Biomarkers in Diabetes (C-EUBD) plays a global role in improving knowledge and understanding around diabetes testing. This paper describes a multi-stakeholder approach, to improving diagnostic and therapeutic testing for diabetes, using a multicentre study in China as an example of the global impact of the group. Methods Educational workshops were developed to support the scientific aims of the study in which 30 centres around China received identical, fresh frozen whole blood samples with values assigned using IFCC secondary reference methods and undertook precision (EP-5) and trueness studies. Performance was assessed using sigma metrics. Results A successful multi-stakeholder group was developed and sustained throughout the study through several educational workshops, which enabled the formation of a long-term collaboration with key opinion leaders and policy makers in China. All 30 centres showed good performance with within and between laboratory coefficient of variations (CVs) below 3% in SI units at both low and high haemoglobin A1c (HbA1c) levels. All individual laboratories met the criteria of a sigma of two or more at a total allowable error (TAE) of 5 mmol/mol (0.46% NGSP). Conclusions The study led to a successful multi-partner approach to improving diabetes testing in China. All centres involved in the study meeting the published IFCC quality criteria, paving the way for future clinical trials and an expanded role for HbA1c testing across the country.
Collapse
Affiliation(s)
- Emma English
- School of Health Sciences, Faculty of Medicine and Health, University of East Anglia, Norwich Research Park, NR4 7TJ, UK
| | - Cas Weykamp
- Department of Clinical Chemistry, Queen Beatrix Hospital, Winterswijk, TheNetherlands.,European Reference Laboratory, Location Queen Beatrix Hospital, Winterswijk, TheNetherlands
| | - Linong Ji
- Peking University People's Hospital, Beijing, P.R.China
| | - Carla Siebelder
- Department of Clinical Chemistry, Queen Beatrix Hospital, Winterswijk, TheNetherlands.,European Reference Laboratory, Location Queen Beatrix Hospital, Winterswijk, TheNetherlands
| | - Zhongyan Shan
- First Hospital of China Medical University, Shenyang, P.R.China
| | - Yufei Wang
- Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai Diabetes Institute, Shanghai, P.R.China
| | - Huijun Li
- Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R.China
| | - W Garry John
- Department of Clinical Biochemistry and Immunology, Norfolk and Norwich University Hospital, Norwich, UK
| |
Collapse
|
7
|
Weykamp C. External quality assessment of HbA1c; Lessons learnt and future prospects for quality targets. Clin Chim Acta 2019. [DOI: 10.1016/j.cca.2019.03.1455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
8
|
den Elzen WPJ, Cobbaert CM, Klein Gunnewiek JMT, Bakkeren DL, van Berkel M, Frasa MAM, Herpers RLJM, Kuypers AWHM, Ramakers C, Roelofsen-de Beer RJAC, van der Vuurst H, Weykamp C. Glucose and total protein: unacceptable interference on Jaffe creatinine assays in patients. Clin Chem Lab Med 2019; 56:e185-e187. [PMID: 29397380 DOI: 10.1515/cclm-2017-1170] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 01/09/2018] [Indexed: 11/15/2022]
Affiliation(s)
- Wendy P J den Elzen
- Department of Clinical Chemistry and Laboratory Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Christa M Cobbaert
- Department of Clinical Chemistry and Laboratory Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Dirk L Bakkeren
- Department of Clinical Chemistry, Máxima Medisch Centrum, Veldhoven, The Netherlands
| | - Miranda van Berkel
- Department of Laboratory Medicine, Radboudumc, Nijmegen, The Netherlands
| | - Marieke A M Frasa
- Department of Clinical Chemistry and Hematology, LangeLand Ziekenhuis, Zoetermeer, The Netherlands
| | | | - Aldy W H M Kuypers
- Department of Clinical Chemistry and Hematology, Maasziekenhuis Pantein, Beugen, The Netherlands
| | - Christian Ramakers
- Department of Clinical Chemistry, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | - Hans van der Vuurst
- Department of Clinical Chemistry, Queen Beatrix Hospital, Winterswijk, The Netherlands
| | - Cas Weykamp
- Department of Clinical Chemistry, Queen Beatrix Hospital, Winterswijk, The Netherlands
| |
Collapse
|
9
|
Weykamp C, John WG, English E, Erasmus RT, Sacks DB, Buchta C, Mueller MM, Lenga Y, Budina M, Kratochvila J, Friedecky B, Siest JP, Kaiser P, Haliassos A, Panagiotakis O, Makris K, Graham H, Kane A, Smith TP, Barrett N, Sciacovelli L, Plebani M, Faria AA, Cardoso A, Correia H, Alemany MV, Alsina CP, Gómez CG, Nordin G, Persson CK, Fried R, Akcadag F, Akgöz M, Aslan D, Jones S, Thomas A, Gillery P, Jaisson S, Mosca A, Paleari R, Slingerland RJ, Slootstra J, Leppink S, Elmgren A, Little RR, Connolly SM, Makky V, Nowicki M, Siebelder C, Schröer-Janssen L, te Winkel M, de Graaf I, Lenters-Westra E. EurA1c: The European HbA1c Trial to Investigate the Performance of HbA1c Assays in 2166 Laboratories across 17 Countries and 24 Manufacturers by Use of the IFCC Model for Quality Targets. Clin Chem 2018; 64:1183-1192. [DOI: 10.1373/clinchem.2018.288795] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 04/13/2018] [Indexed: 11/06/2022]
Abstract
Abstract
BACKGROUND
A major objective of the IFCC Committee on Education and Use of Biomarkers in Diabetes is to generate awareness and improvement of HbA1c assays through evaluation of the performance by countries and manufacturers.
METHODS
Fresh whole blood and lyophilized hemolysate specimens manufactured from the same pool were used by 17 external quality assessment organizers to evaluate analytical performance of 2166 laboratories. Results were evaluated per country, per manufacturer, and per manufacturer and country combined according to criteria of the IFCC model for quality targets.
RESULTS
At the country level with fresh whole blood specimens, 6 countries met the IFCC criterion, 2 did not, and 2 were borderline. With lyophilized hemolysates, 5 countries met the criterion, 2 did not, and 3 were borderline. At the manufacturer level using fresh whole blood specimens, 13 manufacturers met the criterion, 8 did not, and 3 were borderline. Using lyophilized hemolysates, 7 manufacturers met the criterion, 6 did not, and 3 were borderline. In both country and manufacturer groups, the major contribution to total error derived from between-laboratory variation. There were no substantial differences in performance between groups using fresh whole blood or lyophilized hemolysate samples.
CONCLUSIONS
The state of the art is that 1 of 20 laboratories does not meet the IFCC criterion, but there are substantial differences between country and between manufacturer groups. Efforts to further improve quality should focus on reducing between-laboratory variation. With some limitations, fresh whole blood and well-defined lyophilized specimens are suitable for purpose.
Collapse
|
10
|
den Elzen WP, Cobbaert CM, Weykamp C. Interference of glucose and total protein on Jaffe based creatinine methods: mind the covolume – reply. Clin Chem Lab Med 2018; 56:e190. [DOI: 10.1515/cclm-2018-0269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 03/14/2018] [Indexed: 11/15/2022]
|
11
|
Abstract
HbA1c is a key parameter in diabetes management. For years the test has been used exclusively for monitoring of long-term diabetic control. However, due to improvement of the performance, HbA1c is considered more and more for diagnosis and screening. With this new application, quality demands further increase. A task force of the International Federation of Clinical Chemistry and Laboratory Medicine developed a model to set and evaluate quality targets for HbA1c. The model is based on the concept of total error and takes into account the major sources of analytical errors in the medical laboratory: bias and imprecision. Performance criteria are derived from sigma-metrics and biological variation. This review shows 2 examples of the application of the model: at the level of single laboratories, and at the level of a group of laboratories. In the first example data of 125 individual laboratories of a recent external quality assessment program in the Netherlands are evaluated. Differences between laboratories as well as their relation to method principles are shown. The second example uses recent and 3-year-old data of the proficiency test of the College of American Pathologists. The differences in performance between 26 manufacturer-related groups of laboratories are shown. Over time these differences are quite consistent although some manufacturers improved substantially either by better standardization or by replacing a test. The IFCC model serves all who are involved in HbA1c testing in the ongoing process of better performance and better patient care.
Collapse
Affiliation(s)
- Cas Weykamp
- MCA Laboratory, Queen Beatrix Hospital,
Winterswijk, the Netherlands
- European Reference Laboratory, Queen
Beatrix Hospital, Winterswijk, the Netherlands
- Cas Weykamp, PhD, Queen Beatrix Hospital,
Beatrixpark 1, 7101BN Winterswijk, the Netherlands.
| | - Carla Siebelder
- MCA Laboratory, Queen Beatrix Hospital,
Winterswijk, the Netherlands
- European Reference Laboratory, Queen
Beatrix Hospital, Winterswijk, the Netherlands
| |
Collapse
|
12
|
Falkenburg WJ, von Richthofen HJ, Koers J, Weykamp C, Schreurs MW, Bakker-Jonges LE, Haagen IA, Lems WF, Hamann D, van Schaardenburg D, Rispens T. Clinically relevant discrepancies between different rheumatoid factor assays. ACTA ACUST UNITED AC 2018; 56:1749-1758. [DOI: 10.1515/cclm-2017-0988] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 12/14/2017] [Indexed: 01/12/2023]
Abstract
Abstract
Background:
Accurate measurements of rheumatoid factors (RFs), autoantibodies binding IgG, are important for diagnosing rheumatoid arthritis (RA) and for predicting disease course. Worldwide, various RF assays are being used that differ in technique and target antigens. We studied whether assay choice leads to clinically important discrepancies in RF status and level.
Methods:
RF measurements using four commercial RF assays were compared in 32 RF+ samples. Using enzyme-linked immunosorbent assays (ELISAs), the influence of the target antigen source – human IgG (hIgG) versus rabbit IgG (rIgG) – on measured RF levels was investigated in arthralgia patients and RA patients.
Results:
Substantial discrepancies were found between RF levels measured in the four commercial assays. Six samples (19%) with RF levels below or slightly above the cutoff in the rIgG-based Phadia assay were RF+ in three assays using hIgG as the target antigen, some with very high levels. Direct ELISA comparisons of RF reactivity against hIgG and rIgG estimated that among 173 ACPA+ arthralgia patients, originally RF negative in rIgG-based assays, up to 10% were single positive against hIgG. Monoclonal RFs binding to hIgG and rIgG or hIgG only supported these findings. In a cohort of 69 early RA patients, virtually all RF responses reacted with both targets, although levels were still variable.
Conclusions:
The use of RF assays that differ in technique and target antigen, together with the different specificities of RF responses, leads to discrepancies in RF status and levels. This has important consequences for patient care if RA diagnosis and disease progression assessments are based on RF test results.
Collapse
Affiliation(s)
- Willem J.J. Falkenburg
- Amsterdam Rheumatology and Immunology Center , Reade, Amsterdam , The Netherlands
- Department of Immunopathology, Sanquin Research , Amsterdam , The Netherlands
| | | | - Jana Koers
- Department of Immunopathology, Sanquin Research , Amsterdam , The Netherlands
| | - Cas Weykamp
- Queen Beatrix Hospital , Winterswijk , The Netherlands
| | - Marco W.J. Schreurs
- Department of Immunology, Laboratory Medical Immunology , Erasmus MC University Medical Center Rotterdam , Rotterdam , The Netherlands
| | | | - Inez-Anne Haagen
- Department of Hematology and Clinical Chemistry Laboratories, Onze Lieve Vrouwe Gasthuis , Amsterdam , The Netherlands
| | - Willem F. Lems
- Amsterdam Rheumatology and Immunology Center , Reade, Amsterdam , The Netherlands
- Amsterdam Rheumatology and Immunology Center , VU University Medical Center , Amsterdam , The Netherlands
| | - Dörte Hamann
- Department of Immunopathology and Blood Coagulation, Sanquin Diagnostic Services , Amsterdam , The Netherlands
| | - Dirkjan van Schaardenburg
- Amsterdam Rheumatology and Immunology Center , Reade, Amsterdam , The Netherlands
- Amsterdam Rheumatology and Immunology Center, Academic Medical Center , Amsterdam , The Netherlands
| | - Theo Rispens
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center , University of Amsterdam , Amsterdam , The Netherlands
| |
Collapse
|
13
|
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.
Collapse
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
| | | | | |
Collapse
|
14
|
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.
Collapse
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.
| | | |
Collapse
|
15
|
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.
Collapse
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.
| | | |
Collapse
|
16
|
Jansen RT, Cobbaert CM, Weykamp C, Thelen M. The quest for equivalence of test results: the pilgrimage of the Dutch Calibration 2.000 program for metrological traceability. ACTA ACUST UNITED AC 2018; 56:1673-1684. [DOI: 10.1515/cclm-2017-0796] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 11/17/2017] [Indexed: 01/02/2023]
Abstract
Abstract
Calibration 2.000 was initiated 20 years ago for standardization and harmonization of medical tests. The program also intended to evaluate adequate implementation of the In Vitro Diagnostics (IVD) 98/79/EC directive, in order to ensure that medical tests are fit-for-clinical purpose. The Calibration 2.000 initiative led to ongoing verification of test standardization and harmonization in the Netherlands using commutable external quality assessment (EQA)-tools and a type 1 EQA-design, where feasible. National support was guaranteed by involving all laboratory professionals as well as laboratory technicians responsible for EQA and quality officers. A category 1 EQA-system for general chemistry analytes, harmonizers for specific analytes like hGH and IGF-1, and commutable materials for other EQA-sections have been developed and structurally introduced in the EQA-schemes. The type 1 EQA-design facilitates the dialogue between individual specialists in laboratory medicine and the IVD-industry to reduce lot-to-lot variation and to improve standardization. In such a way, Calibration 2.000 sheds light on the metrological traceability challenges that we are facing and helps the laboratory community to get the issues on the table and resolved. The need for commutable trueness verifiers and/or harmonizers for other medical tests is now seen as paramount. Much knowledge is present in the Netherlands and for general chemistry, humoral immunology and protein chemistry, a few endocrinology tests, and various therapeutic drug monitoring (TDM) tests, commutable materials are available. Also the multi sample evaluation scoring system (MUSE) and the category 1 EQA-design offer many possibilities for permanent education of laboratory professionals to further improve the between and within laboratory variation and the test equivalence.
Collapse
Affiliation(s)
- Rob T.P. Jansen
- SKML , Mercator 1, Toernooiveld 214 , 6525EC Nijmegen , The Netherlands
| | | | - Cas Weykamp
- Queen Beatrix Hospital , MCA Laboratory , Winterswijk , The Netherlands
| | - Marc Thelen
- Amphia Hospital, Clinical Chemistry and Haematology , Breda , The Netherlands
| |
Collapse
|
17
|
Weykamp C, Secchiero S, Plebani M, Thelen M, Cobbaert C, Thomas A, Jassam N, Barth JH, Perich C, Ricós C, Faria AP. Analytical performance of 17 general chemistry analytes across countries and across manufacturers in the INPUtS project of EQA organizers in Italy, the Netherlands, Portugal, United Kingdom and Spain. ACTA ACUST UNITED AC 2017; 55:203-211. [DOI: 10.1515/cclm-2016-0220] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 06/24/2016] [Indexed: 11/15/2022]
Abstract
AbstractBackground:Optimum patient care in relation to laboratory medicine is achieved when results of laboratory tests are equivalent, irrespective of the analytical platform used or the country where the laboratory is located. Standardization and harmonization minimize differences and the success of efforts to achieve this can be monitored with international category 1 external quality assessment (EQA) programs.Methods:An EQA project with commutable samples, targeted with reference measurement procedures (RMPs) was organized by EQA institutes in Italy, the Netherlands, Portugal, UK, and Spain. Results of 17 general chemistry analytes were evaluated across countries and across manufacturers according to performance specifications derived from biological variation (BV).Results:For K, uric acid, glucose, cholesterol and high-density density (HDL) cholesterol, the minimum performance specification was met in all countries and by all manufacturers. For Na, Cl, and Ca, the minimum performance specifications were met by none of the countries and manufacturers. For enzymes, the situation was complicated, as standardization of results of enzymes toward RMPs was still not achieved in 20% of the laboratories and questionable in the remaining 80%.Conclusions:The overall performance of the measurement of 17 general chemistry analytes in European medical laboratories met the minimum performance specifications. In this general picture, there were no significant differences per country and no significant differences per manufacturer. There were major differences between the analytes. There were six analytes for which the minimum quality specifications were not met and manufacturers should improve their performance for these analytes. Standardization of results of enzymes requires ongoing efforts.
Collapse
|
18
|
Raven S, Hautvast J, Steenbergen JV, Akkermans R, Weykamp C, Smits F, Hoebe C, Vossen A. Diagnostic performance of serological assays for anti-HBs testing: Results from a quality assessment program. J Clin Virol 2016; 87:17-22. [PMID: 27987422 DOI: 10.1016/j.jcv.2016.12.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [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: 07/14/2016] [Revised: 12/02/2016] [Accepted: 12/06/2016] [Indexed: 02/06/2023]
Abstract
BACKGROUND Post-vaccination testing after hepatitis B vaccination is indispensable to evaluate long-term immunological protection. Using a threshold level of antibodies against hepatitis B surface antigen (anti-HBs) to define serological protection, implies reproducible and valid measurements of different diagnostic assays. OBJECTIVES In this study we assess the performance of currently used anti-HBs assays. STUDY DESIGN In 2013, 45 laboratories participated in an external quality assessment program using pooled anti-HBs serum samples around the cutoff values 10IU/l and 100IU/l. Laboratories used either Axsym (Abbott Laboratories), Architect (Abbott Laboratories), Access (Beckman-Coulter), ADVIA Centaur anti-HBs2 (Siemens Healthcare Diagnostics), Elecsys, Modular or Cobas (Roche Diagnostics) or Vidas Total Quick (Biomerieux) for anti-HBs titre quantification. We analysed covariance using mixed-model repeated measures. To assess sensitivity/specificity and agreement, a true positive or true negative result was defined as an anti-HBs titre respectively above or below the cutoff value by ≥4 of 6 assays. RESULTS Different anti-HBs assays were associated with statistically significant (P<0.05) differences in anti-HBs titres in all dilutions. Sensitivity and specificity ranged respectively from 64%-100% and 95%-100%. Agreement between assays around an anti-HBs titre cutoff value of 10IU/l ranged from 93%-100% and was 44% for a cutoff value of 100IU/l. CONCLUSIONS Around a cutoff value of 10IU/l use of the Access assay may result in false-negative results. Concerning the cutoff value of 100IU/l, a sample being classified below or above this cutoff relied heavily on the specific assay used, with both the Architect and the Access resulting in false-negative results.
Collapse
Affiliation(s)
- Stijn Raven
- Academic Collaborative Centre for Public Health AMPHI, Department of Primary and Community Care, Radboud University Nijmegen Medical Centre, The Netherlands; Department of Medical Microbiology, School of Public Health and Primary Care (CAPHRI), Maastricht University Medical Center (MUMC+), Maastricht, The Netherlands.
| | - Jeannine Hautvast
- Academic Collaborative Centre for Public Health AMPHI, Department of Primary and Community Care, Radboud University Nijmegen Medical Centre, The Netherlands
| | - Jim van Steenbergen
- Centre for Infectious Disease Control, Netherlands Institute of Public Health and the Environment, Bilthoven, The Netherlands; Centre of Infectious Diseases, Leiden University Medical Centre, Leiden, The Netherlands
| | - Reinier Akkermans
- Academic Collaborative Centre for Public Health AMPHI, Department of Primary and Community Care, Radboud University Nijmegen Medical Centre, The Netherlands
| | - Cas Weykamp
- MCA Laboratory, Queen Beatrix Hospital, Winterswijk, The Netherlands; On behalf of the Dutch Foundation for Quality Assessment in Medical Laboratories (SKML), The Netherlands
| | - Francis Smits
- Academic Collaborative Centre for Public Health AMPHI, Department of Primary and Community Care, Radboud University Nijmegen Medical Centre, The Netherlands
| | - Christian Hoebe
- Department of Sexual Health, Infectious Diseases and Environmental Health, South Limburg Public Health Service, The Netherlands; Department of Medical Microbiology, School of Public Health and Primary Care (CAPHRI), Maastricht University Medical Center (MUMC+), Maastricht, The Netherlands
| | - Ann Vossen
- Department of Medical Microbiology, Leiden University Medical Centre, The Netherlands
| |
Collapse
|
19
|
Weykamp C, Kuypers A, Bakkeren D, Franck P, Loon DV, Gunnewiek JK, Jonge RD, Steigstra H, Cobbaert C. Creatinine, Jaffe, and glucose: another inconvenient truth. Clin Chem Lab Med 2016; 53:e347-9. [PMID: 25996486 DOI: 10.1515/cclm-2015-0258] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 05/04/2015] [Indexed: 12/19/2022]
|
20
|
Jassam N, Weykamp C, Thomas A, Secchiero S, Sciacovelli L, Plebani M, Thelen M, Cobbaert C, Perich C, Ricós C, Paula FA, Barth JH. Post-standardization of routine creatinine assays: are they suitable for clinical applications. Ann Clin Biochem 2016; 54:386-394. [DOI: 10.1177/0004563216664541] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Introduction Reliable serum creatinine measurements are of vital importance for the correct classification of chronic kidney disease and early identification of kidney injury. The National Kidney Disease Education Programme working group and other groups have defined clinically acceptable analytical limits for creatinine methods. The aim of this study was to re-evaluate the performance of routine creatinine methods in the light of these defined limits so as to assess their suitability for clinical practice. Method In collaboration with the Dutch External Quality Assurance scheme, six frozen commutable samples, with a creatinine concentration ranging from 80 to 239 μmol/L and traceable to isotope dilution mass spectrometry, were circulated to 91 laboratories in four European countries for creatinine measurement and estimated glomerular filtration rate calculation. Two out of the six samples were spiked with glucose to give high and low final concentrations of glucose. Results Results from 89 laboratories were analysed for bias, imprecision (%CV) for each creatinine assay and total error for estimated glomerular filtration rate. The participating laboratories used analytical instruments from four manufacturers; Abbott, Beckman, Roche and Siemens. All enzymatic methods in this study complied with the National Kidney Disease Education Programme working group recommended limits of bias of 5% above a creatinine concentration of 100 μmol/L. They also did not show any evidence of interference from glucose. In addition, they also showed compliance with the clinically recommended %CV of ≤4% across the analytical range. In contrast, the Jaffe methods showed variable performance with regard to the interference of glucose and unsatisfactory bias and precision. Conclusion Jaffe-based creatinine methods still exhibit considerable analytical variability in terms of bias, imprecision and lack of specificity, and this variability brings into question their clinical utility. We believe that clinical laboratories and manufacturers should work together to phase out the use of relatively non-specific Jaffe methods and replace them with more specific methods that are enzyme based.
Collapse
Affiliation(s)
- Nuthar Jassam
- Department of Clinical Biochemistry, Harrogate District Foundation Trust, Harrogate, UK
| | - Cas Weykamp
- SKML and Department of Clinical Chemistry, Queen Beatrix Hospital, Winterswijk, the Netherlands
| | - Annette Thomas
- WEQAS, Cardiff and Vale University Health Board, Cardiff, UK
| | - Sandra Secchiero
- Biomedical Research Center, Department of Laboratory Medicine, University Hospital of Padova, Padova, Italy
| | - Laura Sciacovelli
- Biomedical Research Center, Department of Laboratory Medicine, University Hospital of Padova, Padova, Italy
| | - Mario Plebani
- Biomedical Research Center, Department of Laboratory Medicine, University Hospital of Padova, Padova, Italy
| | - Marc Thelen
- SKML and Department for Clinical Chemistry, Amphia Hospital, Breda, the Netherlands
| | - Christa Cobbaert
- SKML and Department of Clinical Chemistry, Leiden University Medical Center, Leiden, the Netherlands
| | - Carmen Perich
- Quality Coordinator of Clinical Laboratory, Hospital Vall d’Hebron, Barcelona, Spain
| | - Carmen Ricós
- Spanish Society of Clinical Chemistry and Molecular Pathology (SEQC), Analytical Quality Commission, Barcelona, Spain
| | - Faria A Paula
- Department of Epidemiology, Unity of External Quality Assessment, National Health Institute Doutor Ricardo Jorge, Lisbon, Portugal
| | - Julian H Barth
- Department of Clinical Biochemistry, Leeds Teaching Hospitals Trust, Leeds, UK
| |
Collapse
|
21
|
Helander A, Wielders J, Anton R, Arndt T, Bianchi V, Deenmamode J, Jeppsson JO, Whitfield JB, Weykamp C, Schellenberg F. Standardisation and use of the alcohol biomarker carbohydrate-deficient transferrin (CDT). Clin Chim Acta 2016; 459:19-24. [DOI: 10.1016/j.cca.2016.05.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 05/02/2016] [Accepted: 05/20/2016] [Indexed: 10/21/2022]
|
22
|
Rohlfing C, Hanson S, Weykamp C, Siebelder C, Higgins T, Molinaro R, Yip PM, Little RR. Effects of hemoglobin C, D, E and S traits on measurements of hemoglobin A1c by twelve methods. Clin Chim Acta 2016; 455:80-3. [PMID: 26828530 PMCID: PMC4966613 DOI: 10.1016/j.cca.2016.01.031] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [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: 12/08/2015] [Revised: 01/19/2016] [Accepted: 01/28/2016] [Indexed: 11/28/2022]
Abstract
BACKGROUND Hemoglobin C, D Punjab, E or S trait can interfere with hemoglobin A1c (HbA1c) results. We assessed whether they affect results obtained with 12 current assay methods. METHODS Hemoglobin AA (HbAA), HbAC, HbAD Punjab, HbAE and HbAS samples were analyzed on one enzymatic, nine ion-exchange HPLC and two Capillary Electrophoresis methods. Trinity ultra(2) boronate affinity HPLC was the comparative method. An overall test of coincidence of least-squared linear regression lines was performed to determine if HbA1c results were statistically significantly different from those of HbAA samples. Clinically significant interference was defined as >7% difference from HbAA at 6 or 9% HbA1c compared to ultra(2) using Deming regression. RESULTS All methods showed statistically significant effects for one or more variants. Clinically significant effects were observed for the Tosoh G8 variant mode and GX (all variants), GX V1.22 (all but HbAE) and G11 variant mode (HbAC). All other methods (Abbott Architect c Enzymatic, Bio-Rad D-100, Variant II NU and Variant II Turbo 2.0, Menarini HA-8180T thalassemia mode and HA-8180V variant mode, Sebia Capillarys 2 and Capillarys 3) showed no clinically significant differences. CONCLUSIONS Several methods showed clinically significant interference with HbA1c results from one or more variants which could adversely affect patient care.
Collapse
Affiliation(s)
- Curt Rohlfing
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, United States.
| | - Steven Hanson
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, United States
| | - Cas Weykamp
- European Reference Laboratory, Location Queen Beatrix Hospital, Winterswijk, The Netherlands
| | - Carla Siebelder
- European Reference Laboratory, Location Queen Beatrix Hospital, Winterswijk, The Netherlands
| | - Trefor Higgins
- DynaLIFE(DX) Diagnostic Laboratory Services, Edmonton, AB, Canada
| | - Ross Molinaro
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, United States
| | - Paul M Yip
- University Health Network, Toronto, ON, Canada; University of Toronto, Toronto, ON, Canada
| | - Randie R Little
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, United States
| |
Collapse
|
23
|
Kaiser P, Spannagl M, van Campenhout C, Lenga Y, Siebelder C, Weykamp C. HbA1c: EQA in Germany, Belgium and the Netherlands using fresh whole blood samples with target values assigned with the IFCC reference system. ACTA ACUST UNITED AC 2016; 54:1769-1775. [DOI: 10.1515/cclm-2016-0123] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 04/07/2016] [Indexed: 01/08/2023]
Abstract
AbstractBackground:External quality assessment/proficiency test (EQA/PT) organizers play an important role in monitoring the performance of HbAMethods:Throughout 2015, ten fresh whole blood samples were supplied to the participants. Aggregated results were evaluated according to the IFCC model for quality targets at four levels: overall, per country, per manufacturer, and per country per manufacturer.Results:Robust results in summer and winter demonstrated the feasibility of organizing an EQA with fresh whole blood samples in three countries. The overall performances, as well as the performance for each country were very similar: results fell within the IFCC criteria. Although substantial differences between results from different manufacturers were present, the performances of laboratories using tests of the same manufacturer were strikingly similar in the three countries, suggesting that the quality of HbA
Collapse
|
24
|
John WG, Little R, Sacks DB, Weykamp C, Lenters-Westra E, Hornsby T, Zhao Z, Siebelder C, Tennill A, English E. Multicentre evaluation of the Premier Hb9210 HbA1c analyser. Clin Chem Lab Med 2015; 53:319-27. [PMID: 25274956 DOI: 10.1515/cclm-2014-0589] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 09/04/2014] [Indexed: 01/14/2023]
Abstract
BACKGROUND The accurate and precise quantification of HbA1c is essential for the diagnosis and routine monitoring of patients with diabetes. We report an evaluation of the Trinity Biotech Premier Hb9210 analyser (Bray, Ireland/Kansas City, MO, USA), a boronate affinity chromatography-based high performance liquid chromatography (HPLC) system for the measurement of glycated haemoglobin. METHODS We evaluated the analytical performance of the Hb9210 as part of a multicentre evaluation. The effect of haemoglobin variants, other potential interferences and the performance in comparison to both the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) and National Glycohemoglobin Standardization Program (NGSP) reference systems, was assessed. Most of the centres participating also act as reference laboratories for both the IFCC standardisation network for HbA1c and the NGSP. RESULTS The combined data from all centres showed total coefficients of variation (CV) of 2.71%, 2.32% and 2.14% at low, medium and high values, respectively, for mmol/mol (SI units) and 1.62%, 1.59% and 1.68% for % (NGSP units), which are well below the recommended upper limits of 3% CV for mmol/mol (SI units) and 2% CV for % (NGSP). The analyser showed a good correlation to HbA1c methods currently used in clinical practice and the IFCC reference method procedure. Haemoglobin variants AC, AS, AE and AD do not affect the measurement of HbA1c. Overall the Hb9210 performs well across the whole analytical range. CONCLUSIONS The Hb9210 performs well and is suitable for clinical application in the analysis of HbA1c.
Collapse
|
25
|
Mosca A, Paleari R, Carobene A, Weykamp C, Ceriotti F. Performance of glycated hemoglobin (HbA1c) methods evaluated with EQAS studies using fresh blood samples: Still space for improvements. Clin Chim Acta 2015; 451:305-9. [DOI: 10.1016/j.cca.2015.10.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 10/15/2015] [Accepted: 10/15/2015] [Indexed: 10/22/2022]
|
26
|
Weykamp C, John G, Gillery P, English E, Ji L, Lenters-Westra E, Little RR, Roglic G, Sacks DB, Takei I. Investigation of 2 models to set and evaluate quality targets for hb a1c: biological variation and sigma-metrics. Clin Chem 2015; 61:752-9. [PMID: 25737535 PMCID: PMC4946649 DOI: 10.1373/clinchem.2014.235333] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [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: 10/28/2014] [Accepted: 01/29/2015] [Indexed: 12/11/2022]
Abstract
BACKGROUND A major objective of the IFCC Task Force on Implementation of HbA1c Standardization is to develop a model to define quality targets for glycated hemoglobin (Hb A1c). METHODS Two generic models, biological variation and sigma-metrics, are investigated. We selected variables in the models for Hb A1c and used data of external quality assurance/proficiency testing programs to evaluate the suitability of the models to set and evaluate quality targets within and between laboratories. RESULTS In the biological variation model, 48% of individual laboratories and none of the 26 instrument groups met the minimum performance criterion. In the sigma-metrics model, with a total allowable error (TAE) set at 5 mmol/mol (0.46% NGSP), 77% of the individual laboratories and 12 of 26 instrument groups met the 2σ criterion. CONCLUSIONS The biological variation and sigma-metrics models were demonstrated to be suitable for setting and evaluating quality targets within and between laboratories. The sigma-metrics model is more flexible, as both the TAE and the risk of failure can be adjusted to the situation-for example, requirements related to diagnosis/monitoring or international authorities. With the aim of reaching (inter)national consensus on advice regarding quality targets for Hb A1c, the Task Force suggests the sigma-metrics model as the model of choice, with default values of 5 mmol/mol (0.46%) for TAE and risk levels of 2σ and 4σ for routine laboratories and laboratories performing clinical trials, respectively. These goals should serve as a starting point for discussion with international stakeholders in the field of diabetes.
Collapse
Affiliation(s)
- Cas Weykamp
- Department of Clinical Chemistry and European Reference Laboratory, Location Queen Beatrix Hospital, Winterswijk, the Netherlands;
| | - Garry John
- Norfolk and Norwich University Hospital, Norwich, UK
| | - Philippe Gillery
- Laboratory of Pediatric Biology and Research, University Hospital of Reims, Reims, France
| | - Emma English
- School of Medicine, University of Nottingham, Royal Derby Hospital Site, Derby, UK
| | - Linong Ji
- Peking University People's Hospital, Beijing, China
| | - Erna Lenters-Westra
- Department of Clinical Chemistry, Isala Clinics, Zwolle, the Netherlands; European Reference Laboratory, Location Isala, Zwolle, the Netherlands
| | - Randie R Little
- Departments of Pathology and Child Health, University of Missouri School of Medicine, Columbia, MO
| | - Gojka Roglic
- Department of Management of Noncommunicable Diseases, World Health Organization, Geneva, Switzerland
| | - David B Sacks
- Department of Laboratory Medicine, NIH, Bethesda, MD
| | - Izumi Takei
- Diabetes and Endocrine Department, Ichikawa General Hospital, Ichikawa, Japan
| |
Collapse
|
27
|
Weykamp C, Kemna E, Leppink S, Siebelder C. Glycation rate of haemoglobins S, C, D, E, J and G, and analytical interference on the measurement of HbA1c with affinity chromatography and capillary electrophoresis. ACTA ACUST UNITED AC 2015; 53:e207-10. [DOI: 10.1515/cclm-2014-1134] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 01/20/2015] [Indexed: 11/15/2022]
|
28
|
Weykamp C, Wielders J, Helander A, Anton RF, Bianchi V, Jeppsson JO, Siebelder C, Whitfield JB, Schellenberg F. Harmonization of Measurement Results of the Alcohol Biomarker Carbohydrate-Deficient Transferrin by Use of the Toolbox of Technical Procedures of the International Consortium for Harmonization of Clinical Laboratory Results. Clin Chem 2014; 60:945-53. [DOI: 10.1373/clinchem.2014.221531] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Abstract
BACKGROUND
The need for equivalent results of routine measurement procedures for the alcohol biomarker carbohydrate-deficient transferrin (CDT) has been recognized by the IFCC. This article describes a project to harmonize CDT as conducted by an IFCC working group initiated for this purpose.
METHODS
We used procedures for achieving harmonization as developed by the Consortium for Harmonization of Clinical Laboratory Results to assess the suitability of a candidate reference measurement procedure (cRMP), candidate reference materials (cRMs), and the success of efforts to achieve harmonization.
RESULTS
CDT measurement procedures in routine use showed good reproducibility (CV 1.1%–2.8%) and linearity (r > 0.990) with variable slopes (0.766–1.065) and intercepts (−0.34 to 0.92) compared to the cRMP. Heterogeneity after simulated harmonization was 4.7%. cRMs of frozen human native sera demonstrated commutability and 3-year stability for routine measurement procedures. The cRMP provided reproducible value assignment to cRMs with an expanded uncertainty (k = 2) of 0.03% at the 1.2% CDT level and 0.06% at the 4.4% CDT level. Harmonization efforts reduced the intermeasurement CV from 8.8% to 3.4%, allowed 99% recovery of the values assigned with the cRMP, and demonstrated 99% of results within the desirable allowable total error. Harmonization was less successful in samples with low CDT and high trisialotransferrin concentrations.
CONCLUSIONS
Harmonization of CDT is possible with frozen human native sera as cRMs with values assigned by use of the cRMP. We propose the cRMP as a candidate international conventional reference measurement procedure and cRMs as candidate international calibrators.
Collapse
Affiliation(s)
- Cas Weykamp
- Department of Clinical Chemistry, Queen Beatrix Hospital, Winterswijk, the Netherlands
| | - Jos Wielders
- Department of Clinical Chemistry, Meander Medical Center, Amersfoort, the Netherlands
| | - Anders Helander
- Department of Laboratory Medicine, Karolinska Institutet, and Karolinska University Laboratory, Clinical Chemistry, Stockholm, Sweden
| | - Raymond F Anton
- The Center for Drug and Alcohol Programs, Medical University of South Carolina, Charleston, SC
| | - Vincenza Bianchi
- Toxicology Reference Laboratory, SS. Antonio e Biagio Hospital, Alessandria, Italy
| | - Jan-Olof Jeppsson
- Department of Laboratory Medicine, Malmö University Hospital, Malmö, Sweden
| | - Carla Siebelder
- Department of Clinical Chemistry, Queen Beatrix Hospital, Winterswijk, the Netherlands
| | | | | |
Collapse
|
29
|
Mosca A, Weykamp C. Feasibility of an EQAS for HbA1c in Italy using fresh blood samples. Clin Chem Lab Med 2014; 52:e151-3. [PMID: 24583462 DOI: 10.1515/cclm-2014-0084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 01/31/2014] [Indexed: 11/15/2022]
|
30
|
Weykamp C, Waenink-Wieggers H, Kemna E, Siebelder C. HbA1c: performance of the Sebia Capillarys 2 Flex Piercing. Clin Chem Lab Med 2014; 51:e129-31. [PMID: 23241674 DOI: 10.1515/cclm-2012-0560] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 11/13/2012] [Indexed: 11/15/2022]
|
31
|
Jansen R, Jassam N, Thomas A, Perich C, Fernandez-Calle P, Faria AP, Correia H, Barth JH, Weykamp C, Cobbaert C, Thelen M, Ricós C. A category 1 EQA scheme for comparison of laboratory performance and method performance: An international pilot study in the framework of the Calibration 2000 project. Clin Chim Acta 2014; 432:90-8. [DOI: 10.1016/j.cca.2013.11.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Revised: 11/05/2013] [Accepted: 11/05/2013] [Indexed: 11/16/2022]
|
32
|
Weykamp C, Franck P, Gunnewiek JK, de Jonge R, Kuypers A, van Loon D, Steigstra H, Cobbaert C. Harmonisation of seven common enzyme results through EQA. ACTA ACUST UNITED AC 2014; 52:1549-55. [DOI: 10.1515/cclm-2014-0458] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 04/30/2014] [Indexed: 11/15/2022]
Abstract
AbstractEquivalent results between different laboratories enable optimal patient care and can be achieved with harmonisation. We report on EQA-initiated national harmonisation of seven enzymes using commutable samples.EQA samples were prepared from human serum spiked with human recombinant enzymes. Target values were assigned with the IFCC Reference Measurement Procedures. The same samples were included at four occasions in the EQA programmes of 2012 and 2013. Laboratories were encouraged to report IFCC traceable results. A parallel study was done to confirm commutability of the samples.Of the 223 participating laboratories, 95% reported IFCC traceable results, ranging from 98% (ASAT) to 87% (amylase). Users of Roche and Siemens (97%) more frequently reported in IFCC traceable results than users of Abbott (91%), Beckman (90%), and Olympus (87%). The success of harmonisation, expressed as the recovery of assigned values and the inter-laboratory CV was: ALAT (recovery 100%; inter-lab CV 4%), ASAT (102%; 4%), LD (98%; 3%), CK (101%; 5%), GGT (98%; 4%), AP (96%; 6%), amylase (99%; 4%). There were no significant differences between the manufacturers. Commutability was demonstrated in the parallel study. Equal results in the same sample in the 2012 and 2013 EQA programmes demonstrated stability of the samples.The EQA-initiated national harmonisation of seven enzymes, using stable, commutable human serum samples, spiked with human recombinant enzymes, and targeted with the IFCC Reference Measurement Procedures, was successful in terms of implementation of IFCC traceable results (95%), recovery of the target (99%), and inter-laboratory CV (4%).
Collapse
|
33
|
Abstract
After the relationship between glycemic control and the HbA1c concentration was demonstrated, many tests have been developed to determine the HbA1c concentration. The test results are standardized to the International Federation of Clinical Chemistry (IFCC) Reference Measurement Procedure (RMP) in harmony with the efforts of the National Glycohemoglobin Standardization Program (NGSP). The longitudinal use of the test requires strict quality management including accreditation of the laboratory, a dedicated internal control design, participation in an external quality assessment (EQA) program (proficiency test), and careful consideration of pre- and post-analytical aspects of the test. Performance goals for optimizing determination of the HbA1c concentration have been described. As an index of long-term glycemic control and a risk predictor, the HbA1c concentration is an indispensable part of routine management of diabetes. Because of the improving quality of the test, the HbA1c concentration is being increasingly applied in the diagnosis of diabetes. There are, however, concerns of this application in point-of-care settings. The HbA1c concentration is also used to achieve stringent control in pregnant diabetic patients. Strict standardization enables the definition of universal reference values and clinical decision limits. This review describes the present status of analytical and clinical aspects of determining the HbA1c concentration and highlights the challenges involved.
Collapse
Affiliation(s)
- Cas Weykamp
- MCA Laboratory, Queen Beatrix Hospital, Winterswijk, Netherlands
| |
Collapse
|
34
|
Kessler A, Siekmann L, Weykamp C, Geilenkeuser WJ, Dreazen O, Middle J, Schumann G. External Quality Assessment Scheme for reference laboratories – review of 8 years’ experience. Clin Chem Lab Med 2013; 51:997-1005. [DOI: 10.1515/cclm-2012-0722] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 10/22/2012] [Indexed: 11/15/2022]
|
35
|
Weykamp C, Wielders JP, Helander A, Anton RF, Bianchi V, Jeppsson JO, Siebelder C, Whitfield JB, Schellenberg F. Toward standardization of carbohydrate-deficient transferrin (CDT) measurements: III. Performance of native serum and serum spiked with disialotransferrin proves that harmonization of CDT assays is possible. Clin Chem Lab Med 2013; 51:991-6. [DOI: 10.1515/cclm-2012-0767] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 10/29/2012] [Indexed: 11/15/2022]
|
36
|
Cobbaert C, Weykamp C, Franck P, de Jonge R, Kuypers A, Steigstra H, Klein Gunnewiek J, van Loon D, Jansen R. Systematic monitoring of standardization and harmonization status with commutable EQA-samples--five year experience from the Netherlands. Clin Chim Acta 2012; 414:234-40. [PMID: 23041212 DOI: 10.1016/j.cca.2012.09.027] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2012] [Revised: 08/26/2012] [Accepted: 09/24/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND Equivalence of results among laboratories is a major mission for medical laboratories. Monitoring of test equivalence is structurally integrated in the Dutch External Quality Assessment (EQA) scheme since 2005. Commutable poolsera, single donation "spy" sera and biological variance tolerance limits have been introduced in the EQA scheme for evaluation of the degree of test equivalence and its determinants. METHODS In the annual cycle scheme 24 samples, covering the (patho)physiological measuring range for 17 analytes, are assayed by 220 participating laboratories at biweekly intervals. Test equivalence was evaluated by calculating overall median interlaboratory coefficients of variation (CVs) and its bias and imprecision components. Data from 2005 and 2010 schemes are evaluated to investigate trends in performance and success of standardization efforts. RESULTS Overall median interlaboratory CVs in 2010 were mostly better than in 2005. Median interlaboratory CVs became <5% for electrolytes and substrates, and <10% for enzymes. Improvement in median interlaboratory CVs over these five years is mainly explained by improved method standardization, especially for enzymes and creatinine. CONCLUSION The Dutch EQA-program proves to be a powerful instrument to evaluate test equivalence. It allows monitoring standardization efforts in a highly effective way and gives insight into remaining standardization potential.
Collapse
|
37
|
Weykamp C, Visser-Dekkers W, Kemna E, Siebelder C. Effects of hemoglobin D and E on the measurement of HbA1c with the modified Menarini/ARKRAY ADAMS A1c HA-8180V analyser. Clin Chim Acta 2012; 414:44-5. [PMID: 23010358 DOI: 10.1016/j.cca.2012.07.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 07/31/2012] [Accepted: 07/31/2012] [Indexed: 11/30/2022]
|
38
|
Abstract
BACKGROUND Proficiency testing (PT), or external quality assessment (EQA), is intended to verify on a recurring basis that laboratory results conform to expectations for the quality required for patient care. CONTENT Key factors for interpreting PT/EQA results are knowledge of the commutability of the samples used and the process used for target value assignment. A commutable PT/EQA sample demonstrates the same numeric relationship between different measurement procedures as that expected for patients' samples. Noncommutable PT/EQA samples frequently have a matrix-related bias of unknown magnitude that limits interpretation of results. PT/EQA results for commutable samples can be used to assess accuracy against a reference measurement procedure or a designated comparison method. In addition, the agreement of the results between different measurement procedures for commutable samples reflects that which would be seen for patients' samples. PT/EQA results for noncommutable samples must be compared to a peer group mean/median of results from participants who use measurement procedures that are expected to have the same or very similar matrix-related bias. Peer group evaluation is used to asses whether a laboratory is using a measurement procedure in conformance to the manufacturer's specifications and/or in conformance to other laboratories using the same technology. A noncommutable PT/EQA sample does not give meaningful information about the relationship of results for patients' samples between different measurement procedures. SUMMARY PT/EQA provides substantial value to the practice of laboratory medicine by assessing the performance of individual laboratories and, when commutable samples are used, the status of standardization or harmonization among different measurement procedures.
Collapse
|
39
|
Lenters-Westra E, Weykamp C, Schindhelm RK, Siebelder C, Bilo HJ, Slingerland RJ. One in five laboratories using various hemoglobin A1c methods do not meet the criteria for optimal diabetes care management. Diabetes Technol Ther 2011; 13:429-33. [PMID: 21355726 DOI: 10.1089/dia.2010.0148] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND We assessed the reference change value (RCV) of currently available hemoglobin A(1c) (HbA(1c)) laboratory assays, which is defined as the critical difference between two consecutive HbA(1c) measurements representing a significant change in health status. METHODS We examined the individual laboratory coefficients of variation (CVs) in the Dutch/Belgian quality scheme based on 24 lyophilized samples and calculated the RCV per laboratory (n = 220) and per assay method. In addition, two pooled whole blood samples were sent to the participating laboratories. The individual laboratory results were compared to the assigned value ± an allowable total error (TE(a)) of 6%. RESULTS At HbA(1c) values of 41.0 mmol/mol (5.9%-Diabetes Control and Complications Trial [DCCT]) and 61.8 mmol/mol (7.8%-DCCT), 99% and 98%, respectively, of the laboratories reported a value within a TE(a) limit of 6%. The analytical CV of the HbA(1c) method used in 78% of the laboratories is <2.4%. The mean RCV at an HbA(1c) value of 53 mmol/mol (7.0%-DCCT) for methods of Bio-Rad is 5.9 mmol/mol (0.59%-DCCT); for Arkray/Menarini, 4.3 mmol/mol (0.43%-DCCT); for Roche, 6.5 mmol/mol (0.65%-DCCT); for Tosoh, 3.3 mmol/mol (0.33%-DCCT); and for other methods, 6.3 mmol/mol (0.63%-DCCT). CONCLUSIONS The analytical performance of the majority of laboratory HbA(1c) methods is within the clinical requirements. However, based on the calculated RCV, 21.8% of the laboratories using different HbA(1c) methods are not able to distinguish an HbA(1c) result of 59 mmol/mol (7.5%-DCCT) from a previous HbA(1c) result of 53 mmol/mol (7.0%-DCCT). It can be presumed that differences in HbA(1c) results of 5 mmol/mol (0.5%-DCCT) do influence treatment decisions.
Collapse
|
40
|
Weykamp C, Lenters-Westra E, van der Vuurst H, Slingerland R, Siebelder C, Visser-Dekkers W. Evaluation of the Menarini/ARKRAY ADAMS A1c HA-8180V analyser for HbA1c. Clin Chem Lab Med 2011; 49:647-51. [PMID: 21323625 DOI: 10.1515/cclm.2011.096] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
BACKGROUND We report an evaluation of the Menarini/ARKRAY ADAMS A1c HA-8180V analyser (HA-8180V), the fifth generation Menarini/ARKRAY ion-exchange HPLC for the measurement of HbA(1c). METHODS We evaluated the analytical performance, the measurement of haemoglobin variants and the performance in comparison to major analytical methods. RESULTS Within-run, between-run and total CV were 0.2%, 0.4% and 0.7% at low HbA(1c) concentrations and 0.2%, 0.2% and 0.4% at high HbA(1c) concentrations, respectively. Trueness revealed a maximum deviation of 0.8 mmol/mol (IFCC units) or 0.1% (NGSP units) over the relevant analytical range. Linearity, carry-over and linear drift were excellent. Labile-HbA(1c), carbamylated haemoglobin, icteric samples and variation in hematocrit did not affect HbA(1c) outcome. Haemoglobin variants AS, AC and F do not affect HbA(1c) outcome and are explicitly identified and correctly quantified. HbA(1c) can not be measured in samples with AE and AD, but these variants are identified correctly. In comparison to other methods used at present, the HA-8180V shows excellent performance. CONCLUSIONS The HA-8180V performs at a high level and is fit for any clinical application.
Collapse
Affiliation(s)
- Cas Weykamp
- European Reference Laboratory, Streekziekenhuis Koningin Beatrix, Winterswijk, The Netherlands.
| | | | | | | | | | | |
Collapse
|
41
|
Helander A, Wielders JPM, Jeppsson JO, Weykamp C, Siebelder C, Anton RF, Schellenberg F, Whitfield JB. Toward standardization of carbohydrate-deficient transferrin (CDT) measurements: II. Performance of a laboratory network running the HPLC candidate reference measurement procedure and evaluation of a candidate reference material. Clin Chem Lab Med 2010; 48:1585-92. [PMID: 21034250 DOI: 10.1515/cclm.2010.322] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [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: 11/15/2022]
Abstract
Carbohydrate-deficient transferrin (CDT) is a descriptive term used for a temporary change in the transferrin glycosylation profile caused by alcohol, and used as a biomarker of chronic high alcohol consumption. The use of an array of methods for measurement of CDT in various absolute or relative amounts, and sometimes covering different transferrin glycoforms, has complicated the comparability of results and caused confusion among medical staff. This situation prompted initiation of an IFCC Working Group on CDT standardization. This second publication of the WG-CDT covers the establishment of a network of reference laboratories running a high-performance liquid chromatography (HPLC) candidate reference measurement procedure, and evaluation of candidate secondary reference materials. The network laboratories demonstrated good and reproducible performance and thus can be used to assign target values for calibrators and controls. A candidate secondary reference material based on native human serum lyophilized with a cryo-/lyoprotectant to prevent protein denaturation was found to be commutable and stable during storage. A proposed strategy for calibration of different CDT methods is also presented. In an external quality assurance study involving 66 laboratories and covering the current routine CDT assays (HPLC, capillary electrophoresis and immunoassay), recalculation of observed results based on the nominal values for the candidate calibrator reduced the overall coefficient of variation from 18.9% to 5.5%. The logistics for distribution of reference materials and review of results were found to be functional, indicating that a full reference system for CDT may soon be available.
Collapse
Affiliation(s)
- Anders Helander
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden.
| | | | | | | | | | | | | | | |
Collapse
|
42
|
Affiliation(s)
- Christa Cobbaert
- Department of Clinical Chemistry, Leiden University Medical Center (LUMC), Leiden, the Netherlands
| | - Cas Weykamp
- MCA Laboratory, Queen Beatrix Hospital, Winterswijk, the Netherlands
| | - Christian V Hulzebos
- Department of Pediatrics, Division of Neonatology, Beatrix Children’s Hospital, University Medical Center Groningen (UMCG), Groningen, the Netherlands
| |
Collapse
|
43
|
Abstract
The attraction of the simple biochemical concept combined with a clinical requirement for a long-term marker of glycolic control in diabetes has made hemoglobin A1c (HbA1c) one of the most important assays undertaken in the medical laboratory. The diversity in the biochemistry of glycation, clinical requirements, and management demands has resulted in a broad range of methods being developed since HbA1c was described in the late 1960s. A range of analytic principles are used for the measurement of HbA1c. The charge difference between hemoglobin A0 and HbA1c has been widely utilized to separate these two fractions, most notably found these days in ion-exchange high-performance liquid chromatography systems; the difference in molecular structure (affinity chromatography and immunochemical methods) are becoming widely available. Different results found in different laboratories using a variety of HbA1c analyses resulted in the need for standardization, most notably in the United States, Japan, and Sweden. Designated comparison methods are now located in these three countries, but as they are arbitrarily chosen and have differences in specificity, results of these methods and the reference values and action limits of the methods differ and only harmonized HbA1c in specific geographic areas. A reference measurement system within the concept of metrological traceability is now globally accepted as the only valid analytic anchor. However, there is still discussion over the units to be reported. The consensus statement of the International Federation of Clinical Chemistry (IFCC), the American Diabetes Association, the International Diabetes Federation, and the European Association for the Study of Diabetes suggests reporting HbA1c in IFCC units (mmol/mol), National Glycohemoglobin Standardization Program units (%), and estimated average glucose (either in mg/dl or mmol/liter). The implementation of this consensus statement raised new questions, to be answered in a concerted action of clinicians, biochemists, external quality assessment organizers, patient groups, and manufacturers.
Collapse
Affiliation(s)
- Cas Weykamp
- Queen Beatrix Hospital, Queen Beatrixpark 1, the Netherlands.
| | | | | |
Collapse
|
44
|
Geistanger A, Arends S, Berding C, Hoshino T, Jeppsson JO, Little R, Siebelder C, Weykamp C. Statistical Methods for Monitoring the Relationship between the IFCC Reference Measurement Procedure for Hemoglobin A1c and the Designated Comparison Methods in the United States, Japan, and Sweden. Clin Chem 2008; 54:1379-85. [DOI: 10.1373/clinchem.2008.103556] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Abstract
Background: The American Diabetes Association (ADA)/European Association for the Study of Diabetes (EASD)/International Diabetes Federation (IDF)/IFCC Consensus Statement on the worldwide standardization of HbA1c states that “… [HbA1c] results are to be reported world-wide in IFCC units … and derived NGSP units … , using the IFCC-NGSP master equation.”
Methods: We describe statistical methods to evaluate and monitor the relationships as expressed in master equations (MEs) between the IFCC Reference Measurement procedure (IFCC-RM) and designated comparison methods (DCMs) [US National Glycohemoglobin Standardization Program (NGSP), Japanese Diabetes Society/Japanese Society for Clinical Chemistry (JDS/JSCC), and Mono-S in Sweden]. We applied these statistics, including uncertainty calculations, to 12 studies in which networks of reference laboratories participated, operating the IFCC-RM and DCMs.
Results: For NGSP and Mono-S, slope, intercept, and derived percentage HbA1c at the therapeutic target show compliance with the respective MEs in all 12 studies. For JDS/JSCC, a slight deviation is seen in slope and derived percentage HbA1c in 2 of the 12 studies. Using the MEs, the uncertainty in an assigned value increases from 0.42 mmol/mol HbA1c (IFCC-RM) to 0.47 (NGSP), 0.49 (JDS/JSCC), and 0.51 (Mono-S).
Conclusions: We describe sound statistical methods for the investigation of relations between networks of reference laboratories. Application of these statistical methods to the relationship between the IFCC-RM and DCMs in the US, Japan, and Sweden shows that they are suitable for the purpose, and the results support the applicability of the ADA/EASD/IDF/IFCC Consensus Statement on HbA1c measurement.
Collapse
Affiliation(s)
- Andrea Geistanger
- Roche Diagnostics GmbH, Department of Biostatistics, Penzberg, Germany
| | - Sabine Arends
- Roche Diagnostics GmbH, Department of Biostatistics, Penzberg, Germany
| | - Christoph Berding
- Roche Diagnostics GmbH, Department of Biostatistics, Penzberg, Germany
| | - Tadao Hoshino
- Institute of Biopathological Medicine, Kanagawa, Japan
| | | | - Randie Little
- University of Missouri School of Medicine, Columbia, MO
| | | | - Cas Weykamp
- Queen Beatrix Hospital, Winterswijk, The Netherlands
| | | |
Collapse
|
45
|
Weykamp C, John WG, Mosca A, Hoshino T, Little R, Jeppsson JO, Goodall I, Miedema K, Myers G, Reinauer H, Sacks DB, Slingerland R, Siebelder C. The IFCC Reference Measurement System for HbA1c: A 6-Year Progress Report. Clin Chem 2008; 54:240-8. [DOI: 10.1373/clinchem.2007.097402] [Citation(s) in RCA: 148] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Abstract
Background: The IFCC Reference Measurement System for hemoglobin (Hb)A1c (IFCC-RM) has been developed within the framework of metrologic traceability and is embedded in a network of 14 reference laboratories. This paper describes the outcome of 12 intercomparison studies (periodic evaluations to control essential elements of the IFCC-RM).
Methods: Each study included: unknown samples (to test individual network laboratories); known samples (controls); recently manufactured calibrators (to check calculated assigned value); stored calibrators (to test stability) and a calibration-set (to calibrate the IFCC-RM). The unknown samples are measured by use of the IFCC-RM and the designated comparison methods [DCMs; the National Glycohemoglobin Standardization Program (NGSP) in the US, Japanese Diabetes Society/Japanese Society for Clinical Chemistry (JDS/JSCC) in Japan, and Mono-S in Sweden] are used to investigate the stability of the Master Equation (ME), the relationship between IFCC-RM and DCMs.
Results: A total of 105 IFCC-RM data sets were evaluated: 95 were approved, 5 were not, and for 5 no data were submitted. Trend analysis of the MEs, expressed as change in percentage HbA1c per year, revealed 0.000% (NGSP, not significant), −0.030%, (JDS/JSCC; significant) and −0.016% (Mono-S; not significant). Evaluation of long-term performance revealed no systematic change over time; 2 laboratories showed significant bias, 1 poor reproducibility. The mean HbA1c determined by laboratories performing mass spectrometry (MS) was the same as the mean determined by laboratories using capillary electrophoresis (CE), but the reproducibility at laboratories using CE was better. One batch of new calibrators was not approved. All stored calibrators were stable.
Conclusion: A sound reference system is in place to ensure continuity and stability of the analytical anchor for HbA1c.
Collapse
Affiliation(s)
- Cas Weykamp
- Queen Beatrix Hospital, Winterswijk, The Netherlands (IFCC-network coordinator)
| | - W Garry John
- Norfolk and Norwich University Hospital, and School of Medicine, Health Policy and Practice, UEA, Norwich, UK
| | - Andrea Mosca
- Centro Interdipartimentale per la Riferibilità Metrologica in Medicina di Laboratorio (CIRME), Università degli Studi di Milano, Milano, Italy
| | - Tadao Hoshino
- Institute of Biopathological Medicine, Kanagawa, Japan (JDS/JSCC network coordinator)
| | - Randie Little
- University of Missouri School of Medicine, Columbia, MO (NGSP network coordinator)
| | - Jan-Olof Jeppsson
- Malmoe University Hospital, Malmoe, Sweden (Coordinator Reference System Sweden)
| | - Ian Goodall
- Austin Pathology, Austin Health, Heidelberg, Australia
| | | | - Gary Myers
- Center for Disease Control and Prevention, Atlanta, GA
| | | | - David B Sacks
- Brigham and Women’s Hospital and Harvard Medical School, Boston, MA
| | | | - Carla Siebelder
- Queen Beatrix Hospital, Winterswijk, The Netherlands (IFCC-network coordinator)
| |
Collapse
|
46
|
Delanghe JR, Cobbaert C, Galteau MM, Harmoinen A, Jansen R, Kruse R, Laitinen P, Thienpont LM, Wuyts B, Weykamp C, Panteghini M. Trueness verification of actual creatinine assays in the European market demonstrates a disappointing variability that needs substantial improvement. An international study in the framework of the EC4 creatinine standardization working group. Clin Chem Lab Med 2008; 46:1319-25. [DOI: 10.1515/cclm.2008.256] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract: The European In Vitro Diagnostics (IVD) directive requires traceability to reference methods and materials of analytes. It is a task of the profession to verify the trueness of results and IVD compatibility.: The results of a trueness verification study by the European Communities Confederation of Clinical Chemistry (EC4) working group on creatinine standardization are described, in which 189 European laboratories analyzed serum creatinine in a commutable serum-based material, using analytical systems from seven companies. Values were targeted using isotope dilution gas chromatography/mass spectrometry. Results were tested on their compliance to a set of three criteria: trueness, i.e., no significant bias relative to the target value, between-laboratory variation and within-laboratory variation relative to the maximum allowable error.: For the lower and intermediate level, values differed significantly from the target value in the Jaffe and the dry chemistry methods. At the high level, dry chemistry yielded higher results. Between-laboratory coefficients of variation ranged from 4.37% to 8.74%. Total error budget was mainly consumed by the bias. Non-compensated Jaffe methods largely exceeded the total error budget. Best results were obtained for the enzymatic method. The dry chemistry method consumed a large part of its error budget due to calibration bias.: Despite the European IVD directive and the growing needs for creatinine standardization, an unacceptable inter-laboratory variation was observed, which was mainly due to calibration differences. The calibration variation has major clinical consequences, in particular in pediatrics, where reference ranges for serum and plasma creatinine are low, and in the estimation of glomerular filtration rate.Clin Chem Lab Med 2008;46:1319–25.
Collapse
|
47
|
John WG, Mosca A, Weykamp C, Goodall I. HbA1c standardisation: history, science and politics. Clin Biochem Rev 2007; 28:163-8. [PMID: 18392123 PMCID: PMC2282401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Significant analytical improvements have occurred since glycated haemoglobin (GHb), measured as total HbA(1), was first used in routine clinical laboratories around 1977. Following the publication of the Diabetes Control and Complications Trial (DCCT) study in 1993 the issue of international standardisation became an important objective for scientists and clinicians. The lack of international standardisation led several countries to develop national standardisation programs. The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) Working Group on Standardisation of HbA(1c) established a true international reference measurement system for HbA(1c) and the successful preparation of pure HbA(1c) calibration material that should lead to further improvements in inter-method and inter-laboratory variability. Reporting of HbA(1c) has been agreed using the units of mmol/mol (IFCC) and percent (National Glycohemoglobin Standardization Program, NGSP).
Collapse
Affiliation(s)
- W Garry John
- Norfolk and Norwich University Hospital, and School of Medicine, Heath Policy and Practice, UEA, Norwich, UK.
| | | | | | | |
Collapse
|
48
|
Libeer JC, Van Hoeyveld E, Kochuyt AM, Weykamp C, Bossuyt X. In vitro determination of allergen-specific serum IgE. Comparative analysis of three methods. Clin Chem Lab Med 2007; 45:413-5. [PMID: 17378743 DOI: 10.1515/cclm.2007.074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
49
|
Taylor A, Angerer J, Arnaud J, Claeys F, Kristiansen J, Mazarrasa O, Menditto A, Patriarca M, Pineau A, Valkonen S, Weykamp C. Differences in national legislation for the implementation of lead regulations included in the European directive for the protection of the health and safety of workers with occupational exposure to chemical agents (98/24/EC). Int Arch Occup Environ Health 2006; 80:254-64. [PMID: 16752159 DOI: 10.1007/s00420-006-0118-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2005] [Accepted: 04/26/2006] [Indexed: 10/24/2022]
Abstract
BACKGROUND The European Council Directive 98/24 on the protection of the health and safety of workers exposed to chemical agents sets out provisions for environmental and biological monitoring, making specific reference to binding limit values and health surveillance measures for those with exposure to lead OBJECTIVES To compare how the Directive has been implemented at a national level in EU countries and to determine whether workers receive equivalent protection. METHODS Information on selected key issues was collected from 14 EU countries by means of a structured questionnaire. RESULTS National occupational exposure limit values generally reflect that set by the Directive (0.15 mg/m(3)), but in five cases lower limits are set. National binding biological limit values range from 20 microg/100 ml blood in one country up to 80 microg/100 ml blood in others. The risk to the unborn child is generally recognised with specific measures for women of child-bearing potential or those that are pregnant or breast feeding. In only three countries are special arrangements included for young workers. Limits at which medical surveillance is put into effect are more consistent at 40 microg/100 ml in most countries. The Directive also refers to guidelines for health surveillance but none have been issued with respect to lead. Thus monitoring strategies and requirements for analytical performance vary considerably. CONCLUSIONS The results of this survey suggest that protection of workers against the risk of exposure to lead at work is far from uniform across the European Union. Such disparity may also have implications on the requirements set at national level for laboratories measuring lead in blood and/or air. In the interest of harmonisation within the EU, further consideration should be given to the Annex II of the EC Directive 98/24, taking into account the suggestions for lower binding limit values for lead; this should include full guidelines for medical surveillance and requirements for laboratories should be issued.
Collapse
Affiliation(s)
- Andrew Taylor
- Centre for Clinical Science and Measurement, School of Biomedical and Life Sciences, University of Surrey, Guildford, GU2 7XH, UK.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Jansen R, Schumann G, Baadenhuijsen H, Franck P, Franzini C, Kruse R, Kuypers A, Weykamp C, Panteghini M. Trueness verification and traceability assessment of results from commercial systems for measurement of six enzyme activities in serum. Clin Chim Acta 2006; 368:160-7. [PMID: 16516877 DOI: 10.1016/j.cca.2005.12.033] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [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: 12/21/2005] [Accepted: 12/22/2005] [Indexed: 11/28/2022]
Abstract
BACKGROUND The in vitro diagnostics directive of the European Union requires traceability to higher order reference measurement procedures and materials for analytes in assuring the result trueness and comparability of laboratory measurements. Manufacturers must ensure that the systems they market are calibrated against available reference systems. Validation of metrologically traceable calibrations is, however, required. METHODS A commutable serum-based material was analyzed in three reference laboratories and target values for six enzymes (ALT, AST, CK, GGT, LD, amylase) were assigned using IFCC reference measurement procedures. 70 laboratories in Germany, Italy, and The Netherlands measured the same enzymes in the material using procedures from six commercial companies. A system for maximum allowable error was developed from the biological variation model and the results of the various procedures were tested on their compliance to trueness and between-laboratory and within-laboratory variations relative to the maximum allowable. RESULTS For ALT results were relatively good. >95% of laboratories using systems from Dade, Olympus, Ortho and Roche are expected to comply traceability within the biologically derived limits, and 94% respectively 89% from Abbott and Beckman. For AST and GGT only Dade respectively Olympus fully complied. For CK all companies showed significant bias. Nevertheless >95% of laboratories applying Abbott, Beckman and Roche systems will comply. Finally, LD and amylase measurements require significant improvement. Some manufacturers continue to sell on the European market assays giving results which are not traceable to the internationally accepted reference systems. CONCLUSIONS The traceability of enzyme measurements obtained with routine procedures to internationally accepted IFCC reference systems is not yet satisfactorily accomplished in clinical practice.
Collapse
Affiliation(s)
- Rob Jansen
- Department of Clinical chemistry, St. Anna Hospital, Post box 90, 5660 AB Geldrop, The Netherlands.
| | | | | | | | | | | | | | | | | |
Collapse
|