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Cleveland MH, He HJ, Milavec M, Bae YK, Vallone PM, Huggett JF. Digital PCR for the characterization of reference materials. Mol Aspects Med 2024; 96:101256. [PMID: 38359699 DOI: 10.1016/j.mam.2024.101256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 01/31/2024] [Accepted: 02/07/2024] [Indexed: 02/17/2024]
Abstract
Well-characterized reference materials support harmonization and accuracy when conducting nucleic acid-based tests (such as qPCR); digital PCR (dPCR) can measure the absolute concentration of a specific nucleic acid sequence in a background of non-target sequences, making it ideal for the characterization of nucleic acid-based reference materials. National Metrology Institutes are increasingly using dPCR to characterize and certify their reference materials, as it offers several advantages over indirect methods, such as UV-spectroscopy. While dPCR is gaining widespread adoption, it requires optimization and has certain limitations and considerations that users should be aware of when characterizing reference materials. This review highlights the technical considerations of dPCR, as well as its role when developing and characterizing nucleic acid-based reference materials.
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Affiliation(s)
- Megan H Cleveland
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD, 20899, USA.
| | - Hua-Jun He
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD, 20899, USA
| | - Mojca Milavec
- Department of Biotechnology and Systems Biology, National Institute of Biology, Večna Pot 111, 1000, Ljubljana, Slovenia
| | - Young-Kyung Bae
- Korea Research Institute of Standards and Science (KRISS), Daejeon, Republic of Korea
| | - Peter M Vallone
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD, 20899, USA
| | - Jim F Huggett
- National Measurement Laboratory (NML), LGC, Queens Road, Teddington, TW11 0LY, Middlesex, UK; School of Biosciences & Medicine, Faculty of Health & Medical Science, University of Surrey, Guildford, UK
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2
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Borrillo F, Panteghini M. Current performance of C-reactive protein determination and derivation of quality specifications for its measurement uncertainty. Clin Chem Lab Med 2023; 61:1552-1557. [PMID: 36773318 DOI: 10.1515/cclm-2023-0069] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 01/31/2023] [Indexed: 02/13/2023]
Abstract
From External Quality Assessment data, current harmonization of CRP measuring systems appears to be satisfactory, the inter-assay CV being well below 10%. The inter-method variability is even better (close to 3%) when the widely used measuring systems are compared at CRP concentrations employed as cut-off for detecting sub-clinical infection (i.e., 10.0 mg/L) and measurement variability estimated, according to ISO 20914:2019 Technical Specification, from the intermediate within-lab reproducibility of 6-month consecutive measurement data. According to the state-of-the-art model (which is better suited for CRP), the maximum allowable measurement uncertainty (MAU) for CRP measurement on clinical samples with 10.0 mg/L concentrations is 3.76% (desirable quality). As measurement uncertainty (MU) of the only available reference material (ERM-DA474/IFCC) is ∼3%, to fulfil desirable MAU on clinical samples, IVD manufacturers should work to keep the contribution of remaining MU sources (commercial calibrator and intermediate within-lab reproducibility) lower than 2.3%.
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Affiliation(s)
- Francesca Borrillo
- UOC Patologia Clinica, ASST Fatebenefratelli-Sacco, Milano, Italy
- Research Centre for Metrological Traceability in Laboratory Medicine (CIRME), University of Milan, Milan, Italy
| | - Mauro Panteghini
- UOC Patologia Clinica, ASST Fatebenefratelli-Sacco, Milano, Italy
- Research Centre for Metrological Traceability in Laboratory Medicine (CIRME), University of Milan, Milan, Italy
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Panteghini M. Developments in reference measurement systems for C-reactive protein and the importance of maintaining currently used clinical decision-making criteria. Clin Chem Lab Med 2023; 61:1537-1539. [PMID: 37267501 DOI: 10.1515/cclm-2023-0558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Affiliation(s)
- Mauro Panteghini
- Research Centre for Metrological Traceability in Laboratory Medicine (CIRME), University of Milan, Milan, Italy
- Joint Committee for Traceability in Laboratory Medicine (JCTLM) Task Force on Reference Measurement System Implementation, Milan, Italy
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Lapić I, Šegulja D, Dukić K, Bogić A, Lončar Vrančić A, Komljenović S, Šparakl T, Grdiša Teodorović K, Cigula Kurajica V, Baršić Lapić I, Kralik Oguić S, Kozmar A, Vogrinc Ž, Rogić D. Analytical validation of 39 clinical chemistry tests and 17 immunoassays on the Alinity analytical system. Scandinavian Journal of Clinical and Laboratory Investigation 2022; 82:199-209. [DOI: 10.1080/00365513.2022.2056856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Ivana Lapić
- Department of Laboratory Diagnostics, University Hospital Center Zagreb, Zagreb, Croatia
| | - Dragana Šegulja
- Department of Laboratory Diagnostics, University Hospital Center Zagreb, Zagreb, Croatia
| | - Kristina Dukić
- Department of Laboratory Diagnostics, University Hospital Center Zagreb, Zagreb, Croatia
| | - Anamarija Bogić
- Department of Laboratory Diagnostics, University Hospital Center Zagreb, Zagreb, Croatia
| | - Ana Lončar Vrančić
- Department of Laboratory Diagnostics, University Hospital Center Zagreb, Zagreb, Croatia
| | - Sven Komljenović
- Department of Laboratory Diagnostics, University Hospital Center Zagreb, Zagreb, Croatia
| | - Tajana Šparakl
- Department of Laboratory Diagnostics, University Hospital Center Zagreb, Zagreb, Croatia
| | | | - Vlasta Cigula Kurajica
- Department of Laboratory Diagnostics, University Hospital Center Zagreb, Zagreb, Croatia
| | - Ivana Baršić Lapić
- Department of Laboratory Diagnostics, University Hospital Center Zagreb, Zagreb, Croatia
| | - Saša Kralik Oguić
- Department of Laboratory Diagnostics, University Hospital Center Zagreb, Zagreb, Croatia
| | - Ana Kozmar
- Department of Laboratory Diagnostics, University Hospital Center Zagreb, Zagreb, Croatia
| | - Željka Vogrinc
- Department of Laboratory Diagnostics, University Hospital Center Zagreb, Zagreb, Croatia
| | - Dunja Rogić
- Department of Laboratory Diagnostics, University Hospital Center Zagreb, Zagreb, Croatia
- Faculty of Pharmacy and Biochemistry, University of Zagreb, Zagreb, Croatia
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5
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Joyce CM, Deasy S, Abu H, Lim YY, O'Shea PM, O'Donoghue K. Reference values for C-reactive protein and procalcitonin at term pregnancy and in the early postnatal period. Ann Clin Biochem 2021; 58:452-460. [PMID: 33730872 DOI: 10.1177/00045632211005807] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Early recognition of sepsis and prompt treatment improves patient outcome. C-reactive protein is a sensitive marker for tissue damage and inflammation, but procalcitonin has greater specificity for bacterial infection. Limited research exists regarding the use of C-reactive protein and procalcitonin at term pregnancy and the immediate postpartum period. AIM This study sought to define reference values for C-reactive protein and procalcitonin at term and the early postnatal period. METHODS A prospective cross-sectional study was performed in a university teaching hospital. Venous blood was collected from healthy women (n = 196), aged between 19 and 45 years with an uncomplicated singleton pregnancy, at term (37-40 weeks' gestation) and on day 1 and day 3 postpartum for the measurement of C-reactive protein and procalcitonin. RESULTS The reference population comprised of 189 participants: term pregnancy (n = 51), postpartum day 1 vaginal delivery (n = 70) and caesarean section (n = 38) and day 3 (caesarean section, n = 30). The maximum procalcitonin value at term pregnancy was 0.1 μg/L. On day 1 postpartum, 90% and 86.8% of procalcitonin results for vaginal delivery and caesarean section, respectively, were below the decision-threshold of 0.25 μg/L. The specificity of procalcitonin to rule out infection in the reference population was 91.5%. CONCLUSIONS Reference values for procalcitonin were established in a well-characterized population of healthy pregnant women at term and immediately postpartum. The variability of C-reactive protein limits its clinical utility in the assessment of systemic sepsis. Application of the procalcitonin cut-off of 0.25 μg/L in this population will be a valuable adjunct to clinicians ruling out infection in pregnancy and postpartum.
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Affiliation(s)
- Caroline M Joyce
- Department of Clinical Biochemistry, Cork University Hospital, Cork, Ireland.,Department of Obstetrics & Gynaecology, University College Cork, Cork, Ireland
| | - Shane Deasy
- Department of Clinical Biochemistry, Cork University Hospital, Cork, Ireland
| | - Hala Abu
- Department of Obstetrics and Gynaecology, Cork University Maternity Hospital, Cork, Ireland
| | - Yoke Yin Lim
- Department of Obstetrics and Gynaecology, Cork University Maternity Hospital, Cork, Ireland
| | - Paula M O'Shea
- Department of Clinical Biochemistry, Galway University Hospitals, Galway, Ireland.,School of Medicine, National University of Ireland Galway, Galway, Ireland
| | - Keelin O'Donoghue
- Department of Obstetrics & Gynaecology, University College Cork, Cork, Ireland.,Department of Obstetrics and Gynaecology, Cork University Maternity Hospital, Cork, Ireland.,The Irish Centre for Maternal and Child Health Research (INFANT), University College Cork, Cork, Ireland
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6
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Monogioudi E, Martos G, Sheldon J, Meroni PL, Trapmann S, Zegers I. Development of a certified reference material for anti-β2-glycoprotein I IgG - commutability studies. Clin Chem Lab Med 2020; 59:325-332. [PMID: 33001848 DOI: 10.1515/cclm-2020-0995] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 09/16/2020] [Indexed: 11/15/2022]
Abstract
Objectives In this paper, we describe the steps followed for the development of a certified reference material for immunoglobulin G antibodies against β2-glycoprotein I (also known as apolipoprotein H). These steps include processing of the material, commutability, the impact of dilution, the appropriate reconstitution conditions, homogeneity and stability during transport and storage. Methods We analysed 69 clinical samples from patients suffering from antiphospholipid syndrome with several commercial enzyme-linked immunosorbent assays (ELISA) purchased from in vitro diagnostic manufacturers. Results Analysis of the results indicated that the candidate reference material can be safely freeze-dried, and that the user should carefully follow the reconstitution instructions as small changes in e.g. temperature may have unwanted effects. The statistical analysis of the commutability studies indicated that the analytical response of the reference material upon dilution is similar to that of clinical samples, and that correlation between results may differ from assay to assay. Finally yet importantly, the presented and developed candidate reference material is commutable for most assays tested, homogeneous and stable. Conclusions Immunoglobulin G antibodies against β2-glycoprotein I are associated with a higher risk of thrombosis and pregnancy complications. Their measurement is essential for the diagnosis and monitoring of antiphospholipid syndrome. These antibodies are detected by specific immunoassays, routinely used in clinical diagnostics, but various of these methods show enormous variability, in part due to the lack of a reference material.
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Affiliation(s)
| | - Gustavo Martos
- European Commission - Joint Research Centre (JRC), Geel, Belgium.,International Bureau of Weights and Measures, Sèvres, France
| | - Joanna Sheldon
- St. George's Hospital, Protein Reference Unit, London, UK
| | - Pier Luigi Meroni
- University of Milan, IRCCS Instituto Auxologico Italiano, Milan, Italy
| | | | - Ingrid Zegers
- European Commission - Joint Research Centre (JRC), Geel, Belgium
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Unlocking the Value of White Blood Cells for Heart Failure Diagnosis. J Cardiovasc Transl Res 2020; 14:53-62. [PMID: 32367341 PMCID: PMC7892730 DOI: 10.1007/s12265-020-10007-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 04/15/2020] [Indexed: 02/02/2023]
Abstract
Cardiovascular disease (CVD) is the single greatest cause of mortality and morbidity worldwide. Inciting 85% of CVD fatalities is heart failure, often resulting in or from a myocardial infarction. Early detection along with pharmacological treatment and lifestyle adaptation can result in better prognosis. Biomarkers are molecular or physiological measures that indicate disease presence, status, and severity. However, not all forms of heart failure are created equal. Current mainstay biomarkers for heart failure, including NT-pro-BNP and ejection fraction, lack sensitivity for many patients. Circulating white blood cells and peripheral blood mononuclear cells (PBMCs) are emerging as surrogate biopsies, reflecting molecular changes in the heart. We discuss the advantages of PBMCs over other sources, as well as limitations and considerations. We urge medical center biobanks to collect, isolate and store circulating white blood cells as a rich source of biomarkers to catalyze the discovery of novel diagnostic tools for heart failure.
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Takač B, Mihaljević S, Glavaš-Obrovac L, Kibel A, Suver-Stević M, Canecki-Varžić S, Samardžija M, Rajkovac I, Kovač D, Štefanić M. INTERACTIONS AMONG INTERLEUKIN-6, C-REACTIVE PROTEIN AND INTERLEUKIN-6 (-174) G/C POLYMORPHISM IN THE PATHOGENESIS OF CROHN'S DISEASE AND ULCERATIVE COLITIS. Acta Clin Croat 2020; 59:67-80. [PMID: 32724277 PMCID: PMC7382872 DOI: 10.20471/acc.2020.59.01.09] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Inflammatory bowel diseases are multifactorial disorders the clinical manifestation of which depends on the interaction among immune response, genetic and environmental factors. There is growing evidence that cytokines and gene polymorphisms have an important role in disease pathogenesis in various populations although molecular mechanism of their signaling and interactions is not fully understood yet. The present study aimed at exploring the effects of interleukin-6, C-reactive protein and interleukin-6 rs1800795 polymorphism on the development of Crohn’s disease, ulcerative colitis and inflammatory bowel diseases overall and at determining differences between inflammatory bowel disease patients and healthy controls. A total of 132 inflammatory bowel disease patients and 71 healthy blood donors were investigated. In order to assess the clinical relevance of interleukin-6 and C-reactive protein serum concentration and interleukin-6 rs1800795 single nucleotide polymorphism in patients with Crohn’s disease and ulcerative colitis, we performed a cross-sectional, case-control study. Quantitative assessment of serum interleukin-6 and C-reactive protein was performed with solid-phase, enzyme-labeled, chemiluminescent sequential immunometric and immunoturbidimetric assay, respectively. A real-time fluorescence resonance energy transfer-based method on a LightCyclerTM PCR 1.2 was used for genotyping of IL-6 rs1800795 polymorphism. Both interleukin-6 and C-reactive protein serum levels were elevated in Crohn’s disease and ulcerative colitis patients. Positive correlations were observed between C-reactive protein and interleukin-6 serum concentration and ulcerative colitis activity index as measured by modified Truelove-Witt’s severity index scale. C-reactive protein serum level was higher in Crohn’s disease patients without intestinal resection than in Crohn’s disease patients with prior intestinal resection. In ulcerative colitis patients, interleukin-6 and C-reactive protein serum levels were statistically significantly higher in CC interleukin-6 genotype in comparison to GG+GC genotype. Analysis of the promoter region of the interleukin-6 rs1800795 gene polymorphism showed no statistically significant difference in allele frequency either between inflammatory bowel disease patients and healthy controls or between the two inflammatory bowel disease phenotypes and healthy controls. Associations presented in this study give a potentially important insight into the role of interleukin-6 and C-reactive protein signaling and interleukin-6 polymorphism in the pathogenesis of Crohn’s disease and ulcerative colitis disease.
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Affiliation(s)
| | - Silvio Mihaljević
- 1Department of Nuclear Medicine and Radiation Protection, Osijek University Hospital Centre, Osijek, Croatia; 2Department of Internal Medicine, Division of Gastroenterology, Osijek University Hospital Centre, Osijek, Croatia; 3Josip Juraj Strossmayer University of Osijek, Faculty of Medicine, Osijek, Croatia; 4Department of Transfusion Medicine, Osijek University Hospital Centre, Osijek, Croatia; 5Department of Internal Medicine, Division of Diabetes, Endocrinology and Metabolism Disorders, Osijek University Hospital Centre, Osijek, Croatia; 6Department of Surgery, Division of Vascular Surgery, Osijek University Hospital Centre, Osijek, Croatia; 7Department of Gastroenterology and Hepatology, Dr. Josip Benčević General Hospital, Slavonski Brod, Croatia
| | - Ljubica Glavaš-Obrovac
- 1Department of Nuclear Medicine and Radiation Protection, Osijek University Hospital Centre, Osijek, Croatia; 2Department of Internal Medicine, Division of Gastroenterology, Osijek University Hospital Centre, Osijek, Croatia; 3Josip Juraj Strossmayer University of Osijek, Faculty of Medicine, Osijek, Croatia; 4Department of Transfusion Medicine, Osijek University Hospital Centre, Osijek, Croatia; 5Department of Internal Medicine, Division of Diabetes, Endocrinology and Metabolism Disorders, Osijek University Hospital Centre, Osijek, Croatia; 6Department of Surgery, Division of Vascular Surgery, Osijek University Hospital Centre, Osijek, Croatia; 7Department of Gastroenterology and Hepatology, Dr. Josip Benčević General Hospital, Slavonski Brod, Croatia
| | - Aleksandar Kibel
- 1Department of Nuclear Medicine and Radiation Protection, Osijek University Hospital Centre, Osijek, Croatia; 2Department of Internal Medicine, Division of Gastroenterology, Osijek University Hospital Centre, Osijek, Croatia; 3Josip Juraj Strossmayer University of Osijek, Faculty of Medicine, Osijek, Croatia; 4Department of Transfusion Medicine, Osijek University Hospital Centre, Osijek, Croatia; 5Department of Internal Medicine, Division of Diabetes, Endocrinology and Metabolism Disorders, Osijek University Hospital Centre, Osijek, Croatia; 6Department of Surgery, Division of Vascular Surgery, Osijek University Hospital Centre, Osijek, Croatia; 7Department of Gastroenterology and Hepatology, Dr. Josip Benčević General Hospital, Slavonski Brod, Croatia
| | - Mirjana Suver-Stević
- 1Department of Nuclear Medicine and Radiation Protection, Osijek University Hospital Centre, Osijek, Croatia; 2Department of Internal Medicine, Division of Gastroenterology, Osijek University Hospital Centre, Osijek, Croatia; 3Josip Juraj Strossmayer University of Osijek, Faculty of Medicine, Osijek, Croatia; 4Department of Transfusion Medicine, Osijek University Hospital Centre, Osijek, Croatia; 5Department of Internal Medicine, Division of Diabetes, Endocrinology and Metabolism Disorders, Osijek University Hospital Centre, Osijek, Croatia; 6Department of Surgery, Division of Vascular Surgery, Osijek University Hospital Centre, Osijek, Croatia; 7Department of Gastroenterology and Hepatology, Dr. Josip Benčević General Hospital, Slavonski Brod, Croatia
| | - Silvija Canecki-Varžić
- 1Department of Nuclear Medicine and Radiation Protection, Osijek University Hospital Centre, Osijek, Croatia; 2Department of Internal Medicine, Division of Gastroenterology, Osijek University Hospital Centre, Osijek, Croatia; 3Josip Juraj Strossmayer University of Osijek, Faculty of Medicine, Osijek, Croatia; 4Department of Transfusion Medicine, Osijek University Hospital Centre, Osijek, Croatia; 5Department of Internal Medicine, Division of Diabetes, Endocrinology and Metabolism Disorders, Osijek University Hospital Centre, Osijek, Croatia; 6Department of Surgery, Division of Vascular Surgery, Osijek University Hospital Centre, Osijek, Croatia; 7Department of Gastroenterology and Hepatology, Dr. Josip Benčević General Hospital, Slavonski Brod, Croatia
| | - Marko Samardžija
- 1Department of Nuclear Medicine and Radiation Protection, Osijek University Hospital Centre, Osijek, Croatia; 2Department of Internal Medicine, Division of Gastroenterology, Osijek University Hospital Centre, Osijek, Croatia; 3Josip Juraj Strossmayer University of Osijek, Faculty of Medicine, Osijek, Croatia; 4Department of Transfusion Medicine, Osijek University Hospital Centre, Osijek, Croatia; 5Department of Internal Medicine, Division of Diabetes, Endocrinology and Metabolism Disorders, Osijek University Hospital Centre, Osijek, Croatia; 6Department of Surgery, Division of Vascular Surgery, Osijek University Hospital Centre, Osijek, Croatia; 7Department of Gastroenterology and Hepatology, Dr. Josip Benčević General Hospital, Slavonski Brod, Croatia
| | - Ines Rajkovac
- 1Department of Nuclear Medicine and Radiation Protection, Osijek University Hospital Centre, Osijek, Croatia; 2Department of Internal Medicine, Division of Gastroenterology, Osijek University Hospital Centre, Osijek, Croatia; 3Josip Juraj Strossmayer University of Osijek, Faculty of Medicine, Osijek, Croatia; 4Department of Transfusion Medicine, Osijek University Hospital Centre, Osijek, Croatia; 5Department of Internal Medicine, Division of Diabetes, Endocrinology and Metabolism Disorders, Osijek University Hospital Centre, Osijek, Croatia; 6Department of Surgery, Division of Vascular Surgery, Osijek University Hospital Centre, Osijek, Croatia; 7Department of Gastroenterology and Hepatology, Dr. Josip Benčević General Hospital, Slavonski Brod, Croatia
| | - Damir Kovač
- 1Department of Nuclear Medicine and Radiation Protection, Osijek University Hospital Centre, Osijek, Croatia; 2Department of Internal Medicine, Division of Gastroenterology, Osijek University Hospital Centre, Osijek, Croatia; 3Josip Juraj Strossmayer University of Osijek, Faculty of Medicine, Osijek, Croatia; 4Department of Transfusion Medicine, Osijek University Hospital Centre, Osijek, Croatia; 5Department of Internal Medicine, Division of Diabetes, Endocrinology and Metabolism Disorders, Osijek University Hospital Centre, Osijek, Croatia; 6Department of Surgery, Division of Vascular Surgery, Osijek University Hospital Centre, Osijek, Croatia; 7Department of Gastroenterology and Hepatology, Dr. Josip Benčević General Hospital, Slavonski Brod, Croatia
| | - Mario Štefanić
- 1Department of Nuclear Medicine and Radiation Protection, Osijek University Hospital Centre, Osijek, Croatia; 2Department of Internal Medicine, Division of Gastroenterology, Osijek University Hospital Centre, Osijek, Croatia; 3Josip Juraj Strossmayer University of Osijek, Faculty of Medicine, Osijek, Croatia; 4Department of Transfusion Medicine, Osijek University Hospital Centre, Osijek, Croatia; 5Department of Internal Medicine, Division of Diabetes, Endocrinology and Metabolism Disorders, Osijek University Hospital Centre, Osijek, Croatia; 6Department of Surgery, Division of Vascular Surgery, Osijek University Hospital Centre, Osijek, Croatia; 7Department of Gastroenterology and Hepatology, Dr. Josip Benčević General Hospital, Slavonski Brod, Croatia
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Performance evaluation of 14 specific proteins measurement checked by an External Quality Assessment Scheme. Clin Chim Acta 2019; 502:73-83. [PMID: 31836500 DOI: 10.1016/j.cca.2019.11.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 11/18/2019] [Accepted: 11/18/2019] [Indexed: 11/23/2022]
Abstract
AIMS OF THE STUDY To evaluate the state-of-the-art of 14 specific proteins measurement; to evaluate the laboratories' performance and the degree of harmonization in reporting results of participants in the External Quality Assessment Program of the Centre of Biomedical Research (CRB). METHODS Overall and system-related inter-laboratory analytical variability (mean CVs%) and between-system differences (mean bias%) were evaluated from data of six EQA cycles 2013-2018. Moreover, we evaluated the analytical performance of participants as well as the units used to express proteins results. RESULTS Overall inter-laboratory variability ranged from 3.8% for haptoglobin (HPT) to 12.5% for α1-antitrypsin (AAT) and decreased for IgA, α2-macroglobulin (A2M) and transferrin (TRF). Mean CVs% were generally higher for Siemens BN and Beckman Immage immunonephelometric systems, but <7.0% for all proteins. Mean bias > 7.0% was observed for BN (IgA, C4, AAT, transthyretin TTR), Siemens Vista (IgA, C4) and Immage (C4), whereas mean bias < -7.0% was found for Immage (AAT), Beckman AU (IgM) and Roche Cobas (C4, TTR, C-reactive protein). The laboratories' performance within the limits ranged from 85.1% of albumin (ALB) to 97.2% of HPT. The census of units employed in 2018, demonstrated that ~ 70% of laboratories still express the results in mg/dL. CONCLUSIONS Despite a reduction in inter-laboratory variability for some proteins, different analytical systems showed both proportional and constant bias between methods. Units used by participants have not been substantially changed and dL is still largely used. The CRB EQA Program, with its performance data sets, is a valuable resource for laboratories and IVD manufacturers and support the goals of harmonization.
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Dellavance A, Baldo DC, Zheng B, Mora RA, Fritzler MJ, Hiepe F, Rönnelid J, Satoh M, Garcia-De La Torre I, Wener MH, Chan EK, Andrade LE. Establishment of an international autoantibody reference standard for human anti-DFS70 antibodies: proof-of-concept study for a novel Megapool strategy by pooling individual specific sera. ACTA ACUST UNITED AC 2019; 57:1754-1763. [DOI: 10.1515/cclm-2019-0087] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 03/14/2019] [Indexed: 01/05/2023]
Abstract
Abstract
Background
International autoantibody standards, traditionally based on material obtained from plasmapheresis of single subjects, represent individual immune response and may not comprehend the heterogeneity of the general population. The anti-DFS70 autoantibody yields a characteristic dense fine speckled (DFS) nuclear pattern on indirect immunofluorescence assay on HEp-2 cells (HEp-2 IFA) and speaks against autoimmunity. We propose a novel strategy for developing autoantibody reference standards, based on stepwise pooling of serum samples from hundreds of individuals with anti-DFS70 antibodies.
Methods
Within a 2-year period, serum samples were selected from routine HEp-2 IFA according to the following criteria: DFS HEp-2 IFA pattern at titer ≥1:640; anti-DFS70 reactivity in three analyte-specific tests (Western blot [WB], enzyme-linked immunosorbent assay [ELISA] and chemiluminescent immunoassay [CLIA]). Aliquots of individual samples were combined into progressively larger pools with stepwise validation of intermediary pools as for individual samples. Validated intermediary pools were merged into a final pool for lyophilization.
Results
A total of 741 validated samples yielded a 750 mL final pool that was lyophilized into thousands of 200 μL-aliquots. Reconstituted aliquots yielded the expected anti-DFS70 reactivity in ELISA, CLIA and WB, as well as high-titer DFS HEp-2 IFA pattern. The appropriate anti-DFS70 reactivity of the lyophilized pool was confirmed by seven international expert centers, using HEp-2 IFA, ELISA, WB and immunoprecipitation.
Conclusions
This proof-of-concept study provides an innovative and efficient strategy to build serum reference standards for autoantibody testing. The anti-DFS70 standard will integrate the panel of standards of Autoantibody Standardization Committee (ASC, www.autoab.org), contributing to education for proper assay validation and interpretation of the DFS pattern and other HEp-2 IFA patterns.
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Affiliation(s)
- Alessandra Dellavance
- Research and Development Division, Fleury Medicine and Health Laboratory , São Paulo , Brazil
| | - Danielle C. Baldo
- Research and Development Division, Fleury Medicine and Health Laboratory , São Paulo , Brazil
| | - Bing Zheng
- Department of Oral Biology , University of Florida , Gainesville, FL , USA
- Department of Laboratory Medicine, Renji Hospital, School of Medicine , Shanghai Jiao Tong University , Shanghai , China
| | - Rodrigo A. Mora
- Department of Oral Biology , University of Florida , Gainesville, FL , USA
| | - Marvin J. Fritzler
- Department of Medicine, Cumming School of Medicine , University of Calgary , Calgary , Alberta , Canada
| | - Falk Hiepe
- Department of Rheumatology and Clinical Immunology , Charité – Universitätmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health , Berlin , Germany
| | - Johan Rönnelid
- Department of Immunology, Genetics and Pathology , Uppsala University , Uppsala , Sweden
| | - Minoru Satoh
- Department of Clinical Nursing , University of Occupational and Environmental Health , Kitakyushu , Japan
| | - Ignacio Garcia-De La Torre
- Department of Immunology and Rheumatology , Hospital General de Occidente and University of Guadalajara , Guadalajara , Mexico
| | - Mark H. Wener
- Division of Rheumatology and Department of Laboratory Medicine , University of Washington , Seattle, WA , USA
| | - Edward K.L. Chan
- Department of Oral Biology , University of Florida , Gainesville, FL , USA
| | - Luis E.C. Andrade
- Rheumatology Division, Escola Paulista de Medicina , Universidade Federal de São Paulo , Rua Botucatu 740 3° andar , 04023-062 São Paulo , Brazil
- Immunology Division, Fleury Medicine and Health Laboratory , São Paulo , Brazil
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Proteoform Analysis to Fulfill Unmet Clinical Needs and Reach Global Standardization of Protein Measurands in Clinical Chemistry Proteomics. Clin Lab Med 2018; 38:487-497. [PMID: 30115393 DOI: 10.1016/j.cll.2018.05.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In clinical testing of protein markers, structure variants of the measurand are often not taken into account. This heterogeneous character of protein measurands in immunoassays often renders test standardization impossible. Consequently, test results from different methods can lead to underdiagnosis or overdiagnosis and, thus, undertreatment or overtreatment of patients. The systematic structural analysis of protein isoforms has been coined proteoform profiling and is performed through mass spectrometry-based proteomics strategies. Knowledge on proteoforms allows refining existing uni-marker tests and moreover has great potential to contribute to the urgent need for new tests to predict prognosis and severity of diseases.
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Secchiero S, Sciacovelli L, Plebani M. Harmonization of units and reference intervals of plasma proteins: state of the art from an External Quality Assessment Scheme. ACTA ACUST UNITED AC 2018; 57:95-105. [DOI: 10.1515/cclm-2017-1172] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 04/03/2018] [Indexed: 01/29/2023]
Abstract
Abstract
Background:
The need to harmonize laboratory information is particularly intense in the field of plasma proteins, considering their clinical impact and relevance in monitoring diseases.
Methods:
We evaluated units and reference intervals (RIs) utilized by participants of the External Quality Assessment Scheme (EQAS) for plasma proteins of the Centre of Biomedical Research. Moreover, we evaluated inter-laboratory analytical variability from 2001 to 2017.
Results:
The census of participants’ units employed in 2017 showed that for albumin (ALB), ~66% of laboratories still used dL instead of L, and for most other proteins, ~70% still expressed the results in mg/dL. Laboratories primarily used the RIs reported in the packaging inserts of their analytical systems, but for each protein, there was a wide variability of RIs, also among laboratories using the same analytical method. Mean CVs% of the 13 certified proteins in the last five EQA cycles ranged from 3.8% of haptoglobin (HPT) to 12.4% of α1-antitrypsin (AAT) and decreased from 2001 to 2017 for most of them, in particular for C3, ALB, α2-macroglobulin (A2M), HPT and transferrin (TRF).
Conclusions:
In the face of a reduction in inter-laboratory variability for a lot of proteins, there has not been a substantial change in the units and in the RIs used by the participants. To change old habits is difficult and requires coordination and collaboration. The EQAS plays an important role in the assessment and monitoring of all elements that contribute to the formulation of laboratory information and may be useful to contribute to their harmonization.
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Affiliation(s)
- Sandra Secchiero
- Centre of Biomedical Research – Department of Laboratory Medicine , University-Hospital of Padova , Via Giustiniani, 2 , 35128 Padova , Italy , Phone: +39-049-821-4490, Fax: +39-049-821-7916
| | - Laura Sciacovelli
- Centre of Biomedical Research , University-Hospital of Padova , Padova , Italy
| | - Mario Plebani
- Centre of Biomedical Research , University-Hospital of Padova , Padova , Italy
- Department of Laboratory Medicine , University-Hospital of Padova , Padova , Italy
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Demily C, Parant F, Cheillan D, Broussolle E, Pavec A, Guillaud O, Restier L, Lachaux A, Bost M. Screening of Wilson's disease in a psychiatric population: difficulties and pitfalls. A preliminary study. Ann Gen Psychiatry 2017; 16:19. [PMID: 28392828 PMCID: PMC5379609 DOI: 10.1186/s12991-017-0142-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 03/25/2017] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Wilson's disease (WD) is a rare autosomal-recessive, inherited disorder caused by a mutation in the copper-transporting gene ATP7B affecting the liver and nervous system. About 30% of patients with WD may initially present with psychiatric symptoms, and diagnosis can be difficult to establish. The objectives of the present preliminary study were [1] to evaluate the relevance of serum copper (Cu) and ceruloplasmin (Cp) measures in hospitalized patients with psychiatric disorders; and [2] to identify possible mutations in the ATP7B gene in patients with abnormal biological copper profile. METHODS All psychiatric patients who participated in this study were hospitalized in Saint-Jean de Dieu Hospital (Lyon, France). Cp was measured by immunoturbidimetry and serum Cu by inductively coupled plasma-optical emission spectrometry. When Cp and serum Cu levels were inferior to, respectively, 0.18 g/L and 0.88 mg/L in combination with atypical psychiatric presentations, complete clinical examinations were performed by multidisciplinary physicians specialized in WD. In addition, mutation detection in the ATP7B gene was performed. RESULTS A total of 269 patients completed the study. (1) 51 cases (19%) showed both decreased Cp and Cu concentrations. (2) Molecular genetic tests were performed in 29 patients, and one ATP7B mutation (heterozygous state) was found in four patients. We identified three different missense mutations: p.His1069Gln, c.3207C>A (exon 14), p.Pro1379Ser, c.4135C>T (exon 21) and p.Thr1434Met, c.4301C>T (exon 21). No pathogenic mutation on either ATP7B allele was detected. CONCLUSION Results of Cp and/or serum Cu concentrations below the normal limits are common in patients with psychiatric disorders and nonrelevant and/or informative for the WD diagnosis. WD diagnosis is based on a combination of clinical and biological arguments. Psychiatric patients with suspicion of WD should be evaluated in a reference center. Trial registration CPP Lyon Sud-Est IVNo 10/044, CNIL No DR-2011-470, Afssaps No B100832-40 and CCTIRS No 10.612 bis, registered 8 June 2010.
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Affiliation(s)
- Caroline Demily
- GénoPsy, Center for the Detection and Management of Psychiatric Disorders of Genetic Origin, Pôle Ouest, Hôpital le Vinatier & UMR 5229 (CNRS & Lyon University), 95 Bld Pinel, 69677 Bron cedex, France
- National Reference Center for Wilson’s disease, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Bron, France
| | - François Parant
- Pharmaco-Toxicology, Biochemistry and Molecular Biology Unit, Hôpital Édouard Herriot, Hospices Civils de Lyon, Lyon, France
| | - David Cheillan
- Laboratory of Inherited Metabolic Diseases, Centre de Biologie Est, Hospices Civils de Lyon, Bron, France
| | - Emmanuel Broussolle
- National Reference Center for Wilson’s disease, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Bron, France
- Neurology Unit C, Cognitive Neurosciences Center, Hôpital Neurologique Pierre Wertheimer, Hospices Civils de Lyon; Claude Bernard-Lyon 1 University; CNRS UMR 5229, Bron, France
| | | | - Olivier Guillaud
- National Reference Center for Wilson’s disease, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Bron, France
- Hepato-Gastroenterology Department, Hôpital Edouard Herriot, Hospices Civils de Lyon, Lyon, France
| | - Lioara Restier
- National Reference Center for Wilson’s disease, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Bron, France
- Gastroenterology, Hepatology and Pediatric Nutrition Department, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Bron, France
| | - Alain Lachaux
- National Reference Center for Wilson’s disease, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Bron, France
- Gastroenterology, Hepatology and Pediatric Nutrition Department, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Bron, France
| | - Muriel Bost
- Laboratory of Inherited Metabolic Diseases, Centre de Biologie Est, Hospices Civils de Lyon, Bron, France
- National Reference Center for Wilson’s disease, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Bron, France
- Pharmaco-Toxicology, Biochemistry and Molecular Biology Unit, Hôpital Édouard Herriot, Hospices Civils de Lyon, Lyon, France
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14
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Helmersson-Karlqvist J, Flodin M, Havelka AM, Xu XY, Larsson A. The Roche Immunoturbidimetric Albumin Method on Cobas c 501 Gives Higher Values Than the Abbott and Roche BCP Methods When Analyzing Patient Plasma Samples. J Clin Lab Anal 2016; 30:677-81. [PMID: 27169354 DOI: 10.1002/jcla.21921] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 12/09/2015] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Serum/plasma albumin is an important and widely used laboratory marker and it is important that we measure albumin correctly without bias. We had indications that the immunoturbidimetric method on Cobas c 501 and the bromocresol purple (BCP) method on Architect 16000 differed, so we decided to study these methods more closely. METHOD A total of 1,951 patient requests with albumin measured with both the Architect BCP and Cobas immunoturbidimetric methods were extracted from the laboratory system. A comparison with fresh plasma samples was also performed that included immunoturbidimetric and BCP methods on Cobas c 501 and analysis of the international protein calibrator ERM-DA470k/IFCC. RESULTS The median difference between the Abbott BCP and Roche immunoturbidimetric methods was 3.3 g/l and the Roche method overestimated ERM-DA470k/IFCC by 2.2 g/l. The Roche immunoturbidimetric method gave higher values than the Roche BCP method: y = 1.111x - 0.739, R² = 0.971. CONCLUSION The Roche immunoturbidimetric albumin method gives clearly higher values than the Abbott and Roche BCP methods when analyzing fresh patient samples. The differences between the two methods were similar at normal and low albumin levels.
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Affiliation(s)
| | - Mats Flodin
- Department of Medical Sciences, Clinical Chemistry, University Hospital, Uppsala, Sweden
| | | | - Xiao Yan Xu
- Department of Medical Sciences, Clinical Chemistry, University Hospital, Uppsala, Sweden
| | - Anders Larsson
- Department of Medical Sciences, Clinical Chemistry, University Hospital, Uppsala, Sweden.
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Hutu DP, Tuddenham E, Monogioudi E, Meroni P, Schimmel H, Sheldon J, Zegers I. First steps in the standardization of immunoglobulin IgG myeloperoxidase-anti-neutrophil cytoplasmic antibody measurements. Clin Exp Immunol 2015; 183:193-205. [PMID: 26386466 PMCID: PMC4711156 DOI: 10.1111/cei.12707] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/17/2015] [Indexed: 11/29/2022] Open
Abstract
The standardization of immunoassays for immunoglobulin (Ig)G myeloperoxidase-anti-neutrophil cytoplasmic antibodies (MPO-ANCA) could contribute to a more accurate diagnosis and follow-up of small vessels-associated vasculitis, a systemic autoimmune disorder that leads to necrosis of blood vessel walls. Despite significant efforts by different groups, the level of comparability of results from commercially available immunoassays used for IgG MPO-ANCA detection is still poor. Therefore, the potential for improvement using reference materials was assessed. The evaluation of a set of 30 patient samples with 11 assays showed that differences between assays result in different interpretations for individual patients. Only 10 of 30 patient samples had the same clinical interpretation among 11 assays applying the cut-off values provided by each respective manufacturer. The correlation between results from 13 different assays was assessed in a pairwise manner. The correlation between results from patient samples was systematically very good for combinations of seven of those assays. The correlation of results ranged from reasonable to good for combinations with four other assays, therefore it should be possible to improve the comparability of results using a commutable reference material for calibration. Feasibility studies were conducted in order to find a reference material format most suitable for a calibrator. Two sets of candidate reference materials were produced from different raw materials, and assessed according to their suitability. A final format was selected, and a candidate reference material was produced.
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Affiliation(s)
- D P Hutu
- Institute for Reference Materials and Measurements (IRMM), Joint Research Centre, European Commission, Geel, Belgium
| | - E Tuddenham
- Protein Reference Unit and Immunopathology Department, St Georges' Hospital, London, UK
| | - E Monogioudi
- Institute for Reference Materials and Measurements (IRMM), Joint Research Centre, European Commission, Geel, Belgium
| | - P Meroni
- Department of Clinical Sciences and Community Health and Istituto Auxologico Italiano, Milan, Italy
| | - H Schimmel
- Institute for Reference Materials and Measurements (IRMM), Joint Research Centre, European Commission, Geel, Belgium
| | - J Sheldon
- Protein Reference Unit and Immunopathology Department, St Georges' Hospital, London, UK
| | - I Zegers
- Institute for Reference Materials and Measurements (IRMM), Joint Research Centre, European Commission, Geel, Belgium
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Minchella PA, Armitage AE, Darboe B, Jallow MW, Drakesmith H, Jaye A, Prentice AM, McDermid JM. Elevated Hepcidin Is Part of a Complex Relation That Links Mortality with Iron Homeostasis and Anemia in Men and Women with HIV Infection. J Nutr 2015; 145:1194-201. [PMID: 25904736 PMCID: PMC4442111 DOI: 10.3945/jn.114.203158] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 03/23/2015] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Early and chronic inflammation is a hallmark of HIV infection, and inflammation is known to increase hepcidin expression. Consequently, hepcidin may be a key determinant of the iron homeostasis and anemia associated with poorer HIV prognoses. OBJECTIVE The objective of this study was to understand how hepcidin is related to anemia, iron homeostasis, and inflammation at HIV diagnosis and to investigate associations between hepcidin and all-cause mortality in HIV infection. METHODS In a retrospective cohort, baseline plasma hepcidin was measured by competitive enzyme immunoassay within 3 mo of HIV diagnosis in 196 antiretroviral-naive Gambians. Iron homeostasis [hemoglobin, plasma transferrin, ferritin, iron, soluble transferrin receptor (sTfR)] and inflammation [α1-antichymotrypsin (ACT)] from the same plasma sample were available, as were absolute CD4 cell counts, age, gender, body mass index (BMI), and HIV type. RESULTS Anemia was common across the spectrum of immunosuppression [CD4 cell counts (prevalence of anemia): >500 cells/μL (68%), 200-500 cells/μL (73%), and <200 cells/μL (89%); P = 0.032] and in men (81%) and women (76%). Increasing hepcidin was associated with iron homeostasis biomarkers (higher ferritin and lower transferrin, hemoglobin, and sTfR), inflammation (higher ACT), and key health indicators (lower CD4 or BMI, advancing age, and male gender; P < 0.001 except for hemoglobin, P = 0.021). Elevated hepcidin was associated with greater all-cause mortality in a dose-dependent manner [intermediate vs. lowest tertile: unadjusted HR (95% CI), 1.95 (1.22, 3.10); upper vs. lowest tertile: 3.02 (1.91, 4.78)]. Principal components analysis identified 2 patterns composed of hepcidin-ferritin-transferrin, with or without ACT, and iron-sTfR-hemoglobin that may distinguish inflammation and erythropoiesis iron functions. CONCLUSIONS Elevated hepcidin is independently associated with greater mortality in men and women with HIV infection, and hepcidin is also part of a complex relation linking iron homeostasis, anemia, and HIV. Understanding the mechanisms and role of hepcidin modulation may further guide evidence-based interventions needed to counter detrimental iron homeostasis and anemia in HIV infection.
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Affiliation(s)
| | - Andrew E Armitage
- Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Bakary Darboe
- Medical Research Council Unit (UK), Fajara, The Gambia
| | | | - Hal Drakesmith
- Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Assan Jaye
- Medical Research Council Unit (UK), Fajara, The Gambia
| | - Andrew M Prentice
- International Nutrition Group, Department of Nutrition and Public Health Intervention Unit, London School of Hygiene and Tropical Medicine, London, United Kingdom; and
| | - Joann M McDermid
- Department of Nutritional Sciences, Cornell University, Ithaca, NY;
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Sheldon J, Dellavance A. Strategies for building reference standards for autoantibodies. Front Immunol 2015; 6:194. [PMID: 25972866 PMCID: PMC4413817 DOI: 10.3389/fimmu.2015.00194] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Accepted: 04/08/2015] [Indexed: 11/13/2022] Open
Abstract
Producing robust, certified, traceable reference material for autoantibody testing is a vital element in maintaining the validity of results that are generated in the daily clinical laboratory routine. This is a huge challenge because of the high number of variables involved in the detection and measurement of the autoantibodies. The production of such materials is time consuming and needs rigorous attention to detail; this is best achieved by an overarching independent body who will oversee the process in a “not for profit” manner. Much effort has been made to build international standards for quantitative and qualitative assays based on monoclonal antibodies, obtained from affinity purification and plasmapheresis. The big challenge is to respect individual differences in immune response to the same antigen. A promising ongoing initiative is the construction of pools with monospecific samples from different individuals.
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Affiliation(s)
- Joanna Sheldon
- Protein Reference Unit, St George's Hospital , London , UK
| | - Alessandra Dellavance
- Research and Development Division, Fleury Medicine and Health Laboratories , São Paulo , Brazil
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18
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Zegers I, Schimmel H. To Harmonize and Standardize: Making Measurement Results Comparable. Clin Chem 2014; 60:911-3. [DOI: 10.1373/clinchem.2014.224477] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Ingrid Zegers
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Geel, Belgium
| | - Heinz Schimmel
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Geel, Belgium
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Verification of in vitro medical diagnostics (IVD) metrological traceability: responsibilities and strategies. Clin Chim Acta 2013; 432:55-61. [PMID: 24291059 DOI: 10.1016/j.cca.2013.11.022] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 09/23/2013] [Accepted: 11/19/2013] [Indexed: 01/20/2023]
Abstract
To be accurate and equivalent, laboratory results should be traceable to higher-order references. Furthermore, their analytical performance should fulfill acceptable measurement uncertainty criteria defined to fit the intended clinical use. With this aim, In Vitro Diagnostics (IVD) manufacturers should define a calibration hierarchy to assign traceable values to their system calibrators and to fulfill during this process uncertainty limits for calibrators, which should represent a proportion of the uncertainty budget allowed for laboratory results. It is important that end-users may know and verify how manufacturers have implemented the traceability of their calibrators and estimated the corresponding uncertainty. However, full information about traceability and combined uncertainty of calibrators is currently not available. Important tools for IVD traceability surveillance are the verification by laboratories of the consistency of declared performance during daily operations performed in accordance with the manufacturer's instructions and the organization of appropriately structured External Quality Assessment (EQA) programs. The former activity should be accomplished by analyzing system control materials and confirming that current measurements are in the manufacturer's established control range. With regard to EQA, it is mandatory that target values for materials are assigned with reference procedures by accredited laboratories, that materials are commutable and that a clinically allowable inaccuracy for participant's results is defined.
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21
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Metrology for metalloproteins—where are we now, where are we heading? Anal Bioanal Chem 2013; 405:5697-723. [DOI: 10.1007/s00216-013-6933-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 03/18/2013] [Accepted: 03/19/2013] [Indexed: 01/10/2023]
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22
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Zegers I, Beetham R, Keller T, Sheldon J, Bullock D, MacKenzie F, Trapmann S, Emons H, Schimmel H. The importance of commutability of reference materials used as calibrators: the example of ceruloplasmin. Clin Chem 2013; 59:1322-9. [PMID: 23649128 DOI: 10.1373/clinchem.2012.201954] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Different methods for ceruloplasmin tend to give different results in external quality assessment schemes. During the production of the certified reference material ERM-DA470k/IFCC discrepant measurement results were also found for ceruloplasmin measured with different methods, and consequently the protein could not be certified in the material. METHODS We performed a commutability study with 30 serum samples and the reference materials ERM-DA470, ERM-DA470k/IFCC, and ERM-DA472/IFCC, using 6 different methods. Data were analyzed according to the CLSI Guideline C53-A to assess whether the reference materials had the same behavior as the serum samples with respect to measurement results obtained with combinations of the methods used. RESULTS Measurement results from different methods showed a good linear correlation for the serum samples. ERM-DA470 showed marked noncommutability for certain combinations of methods. ERM-DA470k/IFCC and ERM-DA472/IFCC were commutable for more combinations of methods. The lack of commutability of ERM-DA470 for certain combinations of methods correlates with results from the UK National External Quality Assessment Service showing discrepancies between results from these methods. For serum stored in the presence of sodium azide the results from different methods are essentially equivalent. CONCLUSIONS Ceruloplasmin in ERM-DA470 is a fully documented example of a situation in which, due to lack of commutability, the use of a common material for calibration did not lead to harmonization .
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Affiliation(s)
- Ingrid Zegers
- Institute for Reference Materials and Measurements (IRMM), Joint Research Centre, European Commission, Geel, Belgium.
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Infusino I, Panteghini M. Serum albumin: Accuracy and clinical use. Clin Chim Acta 2013; 419:15-8. [DOI: 10.1016/j.cca.2013.01.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 01/10/2013] [Accepted: 01/12/2013] [Indexed: 10/27/2022]
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Mattsson N, Zegers I, Andreasson U, Bjerke M, Blankenstein MA, Bowser R, Carrillo MC, Gobom J, Heath T, Jenkins R, Jeromin A, Kaplow J, Kidd D, Laterza OF, Lockhart A, Lunn MP, Martone RL, Mills K, Pannee J, Ratcliffe M, Shaw LM, Simon AJ, Soares H, Teunissen CE, Verbeek MM, Umek RM, Vanderstichele H, Zetterberg H, Blennow K, Portelius E. Reference measurement procedures for Alzheimer's disease cerebrospinal fluid biomarkers: definitions and approaches with focus on amyloid β42. Biomark Med 2013; 6:409-17. [PMID: 22917143 DOI: 10.2217/bmm.12.39] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cerebrospinal fluid (CSF) biomarkers for Alzheimer's disease (AD) are increasingly used in clinical settings, research and drug trials. However, their broad-scale use on different technology platforms is hampered by the lack of standardization at the level of sample handling, determination of concentrations of analytes and the absence of well-defined performance criteria for in vitro diagnostic or companion diagnostic assays, which influences the apparent concentration of the analytes measured and the subsequent interpretation of the data. There is a need for harmonization of CSF AD biomarker assays that can reliably, across centers, quantitate CSF biomarkers with high analytical precision, selectivity and stability over long time periods. In this position paper, we discuss reference procedures for the measurement of CSF AD biomarkers, especially amyloid β42 and tau. We describe possible technical approaches, focusing on a selected reaction monitoring mass spectrometry assay as a candidate reference method for quantification of CSF amyloid β42.
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Affiliation(s)
- Niklas Mattsson
- Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, the Sahlgrenska Academy at University of Gothenburg, Sahlgrenska University Hospital, Mölndal, Sweden.
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Affiliation(s)
- Niklas Mattsson
- Institute of Neuroscience & Physiology, Department of Psychiatry & Neurochemistry, Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden.
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Preparation of highly purified monomeric human serum albumin as secondary reference material for standardization of urinary albumin immunoassays. Clin Chim Acta 2012; 413:175-81. [DOI: 10.1016/j.cca.2011.09.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 09/12/2011] [Accepted: 09/12/2011] [Indexed: 11/20/2022]
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27
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Is the accuracy of serum albumin measurements suitable for clinical application of the test? Clin Chim Acta 2011; 412:791-2. [DOI: 10.1016/j.cca.2011.01.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 12/20/2010] [Accepted: 01/06/2011] [Indexed: 10/18/2022]
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28
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Infusino I, Braga F, Valente C, Panteghini M. Commutability of the ERM-DA470k Reference Material for two assays measuring serum albumin using immunochemical principles. Clin Chem Lab Med 2011; 49:1383-1384. [DOI: 10.1515/cclm.2011.619] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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