1
|
Salaun E, Drory S, Coté M, Tremblay V, Bédard E, Steinberg C, Paré D, O'Connor K, Cieza T, Coté N, Poirier P, Douville P, Blais J, Desmeules P, Kalavrouziotis D, Mohammadi S, Voisine P, Bernier M, Pibarot P, Thériault S. Role of Antitroponin Antibodies and Macrotroponin in the Clinical Interpretation of Cardiac Troponin. J Am Heart Assoc 2024; 13:e035128. [PMID: 38879450 PMCID: PMC11255741 DOI: 10.1161/jaha.123.035128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/19/2024]
Abstract
Cardiac troponin is extensively used as a biomarker in modern medicine due to its diagnostic capability for myocardial injury, as well as its predictive and prognostic value for cardiac diseases. However, heterophile antibodies, antitroponin antibodies, and macrotroponin complexes can be observed both in seemingly healthy individuals and patients with cardiac diseases, potentially leading to false positive or disproportionate elevation of cTn (cardiac troponin) assay results and introducing discrepancies in clinical interpretations with impact on medical management. In this review article, we describe the possible mechanisms of cTn release and the sources of variations in the assessment of circulating cTn levels. We also explore the pathophysiological mechanisms underlying antitroponin antibody development and discuss the influence exerted by macrotroponin complexes on the results of immunoassays. Additionally, we explore approaches to detect these complexes by presenting various clinical scenarios encountered in routine clinical practice. Finally, unsolved questions about the development, prevalence, and clinical significance of cardiac autoantibodies are discussed.
Collapse
Affiliation(s)
- Erwan Salaun
- Institut Universitaire de Cardiologie et de Pneumologie de QuébecUniversité LavalQuébecCanada
| | - Samuel Drory
- Institut Universitaire de Cardiologie et de Pneumologie de QuébecUniversité LavalQuébecCanada
| | - Marc‐André Coté
- Institut Universitaire de Cardiologie et de Pneumologie de QuébecUniversité LavalQuébecCanada
| | - Veronic Tremblay
- Institut Universitaire de Cardiologie et de Pneumologie de QuébecUniversité LavalQuébecCanada
| | - Elisabeth Bédard
- Institut Universitaire de Cardiologie et de Pneumologie de QuébecUniversité LavalQuébecCanada
| | - Christian Steinberg
- Institut Universitaire de Cardiologie et de Pneumologie de QuébecUniversité LavalQuébecCanada
| | - David Paré
- Institut Universitaire de Cardiologie et de Pneumologie de QuébecUniversité LavalQuébecCanada
| | - Kim O'Connor
- Institut Universitaire de Cardiologie et de Pneumologie de QuébecUniversité LavalQuébecCanada
| | - Tomas Cieza
- Institut Universitaire de Cardiologie et de Pneumologie de QuébecUniversité LavalQuébecCanada
| | - Nancy Coté
- Institut Universitaire de Cardiologie et de Pneumologie de QuébecUniversité LavalQuébecCanada
| | - Paul Poirier
- Institut Universitaire de Cardiologie et de Pneumologie de QuébecUniversité LavalQuébecCanada
- Faculty of pharmacyUniversité LavalQuébecCanada
| | - Pierre Douville
- Centre Hospitalier Universitaire de QuébecUniversité LavalQuébecCanada
| | - Jonatan Blais
- Centre Hospitalier Universitaire de QuébecUniversité LavalQuébecCanada
| | - Philippe Desmeules
- Institut Universitaire de Cardiologie et de Pneumologie de QuébecUniversité LavalQuébecCanada
- Centre Hospitalier Universitaire de QuébecUniversité LavalQuébecCanada
| | - Dimitris Kalavrouziotis
- Institut Universitaire de Cardiologie et de Pneumologie de QuébecUniversité LavalQuébecCanada
| | - Siamak Mohammadi
- Institut Universitaire de Cardiologie et de Pneumologie de QuébecUniversité LavalQuébecCanada
| | - Pierre Voisine
- Institut Universitaire de Cardiologie et de Pneumologie de QuébecUniversité LavalQuébecCanada
- Division of Cardiac SurgeryUniversity of Ottawa Heart InstituteOttawaOntarioCanada
| | - Mathieu Bernier
- Institut Universitaire de Cardiologie et de Pneumologie de QuébecUniversité LavalQuébecCanada
| | - Philippe Pibarot
- Institut Universitaire de Cardiologie et de Pneumologie de QuébecUniversité LavalQuébecCanada
| | - Sébastien Thériault
- Institut Universitaire de Cardiologie et de Pneumologie de QuébecUniversité LavalQuébecCanada
| |
Collapse
|
2
|
Lam L. The quality of high-sensitivity troponin assay is critical to length of stay and resource utilization. EUROPEAN HEART JOURNAL. ACUTE CARDIOVASCULAR CARE 2024; 13:296. [PMID: 38198794 DOI: 10.1093/ehjacc/zuae003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 01/03/2024] [Indexed: 01/12/2024]
Affiliation(s)
- Leo Lam
- Chemical Pathology, Auckland City Hospital, Middlemore Hospital and Whangarei Hospital, New Zealand
| |
Collapse
|
3
|
Lam L, Kyle C. Practical approaches to the detection of macrotroponin. Ann Clin Biochem 2024; 61:122-132. [PMID: 37578158 DOI: 10.1177/00045632231197301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
INTRODUCTION Macrotroponin is increasingly recognised as a cause of confusion in interpreting high-sensitivity cardiac troponin (hs-cTnI) results. In this study, we sought to evaluate two practical approaches to detecting macrotroponin. These two approaches are PEG precipitation and SVM (support vector machine) analysis to classify discrepancies between hs-cTn assays. METHOD Residual serum and heparin plasma specimens (n = 483) with initially elevated hs-cTnI from hospital and community laboratories were retested on multiple hs-cTn platforms before and after PEG precipitation and Protein A immunoglobulin depletion. SVM analysis was conducted to identify a linear equation that best discriminated specimens with macrotroponin using a combination of results from two different hs-cTn assays. FINDINGS The diagnostic performance of PEG precipitation was carried out using Protein A immunoglobulin depletion as the reference comparator. When a cutoff residual activity after PEG precipitation of ≤ 20% was used, this threshold carried a high specificity of 92% (confidence interval 83-98%; n = 189) using the Siemens hs-cTnI Vista assay and 95% specificity (86%-98%; n = 242) using the Abbott hs-cTnI Architect assay. SVM analysis generated a linear equation identifying macrotroponin specimens from results obtained on two hs-cTn assays. This approach can be highly specific, comparable to PEG precipitation when certain assay combinations and concentrations are used. CONCLUSION We describe and identify practical alternatives to detecting macrotroponin. These approaches can be optimised for high specificity, reducing the need for more complex laboratory methods.
Collapse
Affiliation(s)
- Leo Lam
- Chemical Pathology, LabPlus, Auckland City Hospital, Auckland, New Zealand
- Biochemistry, Middlemore Hospital Laboratories, Auckland, New Zealand
| | - Campbell Kyle
- Chemical Pathology, LabPlus, Auckland City Hospital, Auckland, New Zealand
- Biochemistry, Labtests, Auckland, New Zealand
| |
Collapse
|
4
|
Hammarsten O, Warner JV, Lam L, Kavsak P, Lindahl B, Aakre KM, Collinson P, Jaffe AS, Saenger AK, Body R, Mills NL, Omland T, Ordonez-Llanos J, Apple FS. Antibody-mediated interferences affecting cardiac troponin assays: recommendations from the IFCC Committee on Clinical Applications of Cardiac Biomarkers. Clin Chem Lab Med 2023; 61:1411-1419. [PMID: 36952681 DOI: 10.1515/cclm-2023-0028] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 01/12/2023] [Indexed: 03/25/2023]
Abstract
The International Federation of Clinical Chemistry Committee on Clinical Applications of Cardiac Biomarkers (IFCC C-CB) provides educational documents to facilitate the interpretation and use of cardiac biomarkers in clinical laboratories and practice. Our aim is to improve the understanding of certain key analytical and clinical aspects of cardiac biomarkers and how these may interplay. Measurements of cardiac troponin (cTn) have a prominent place in the clinical work-up of patients with suspected acute coronary syndrome. It is therefore important that clinical laboratories know how to recognize and assess analytical issues. Two emerging analytical issues resulting in falsely high cTn concentrations, often several fold higher than the upper reference limit (URL), are antibody-mediated assay interference due to long-lived cTn-antibody complexes, called macrotroponin, and crosslinking antibodies that are frequently referred to as heterophilic antibodies. We provide an overview of antibody-mediated cTn assay interference and provide recommendations on how to confirm the interference and interpret the results.
Collapse
Affiliation(s)
- Ola Hammarsten
- Department of Clinical Chemistry and Transfusion Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Janet V Warner
- Faculty of Medicine, The University of Queensland, Saint Lucia, Australia
| | - Leo Lam
- Chemical Pathology, LabPlus, Auckland City Hospital, Auckland, New Zealand
- Biochemistry, Middlemore Hospital Laboratories, Auckland, New Zealand
| | - Peter Kavsak
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | - Bertil Lindahl
- Department of Medical Sciences, Uppsala University and Uppsala Clinical Research Center, Uppsala University, Uppsala, Sweden
| | - Kristin M Aakre
- Department of Medical Biochemistry and Pharmacology and Department of Heart Disease, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Paul Collinson
- Departments of Clinical Blood Sciences and Cardiology, St George's University Hospitals NHS Foundation Trust, London, UK
- St George's University of London, London, UK
| | - Allan S Jaffe
- Departments of Laboratory Medicine and Pathology and Cardiology, Mayo Clinic, Rochester, MN, USA
| | - Amy K Saenger
- Department of Laboratory Medicine and Pathology, Hennepin Healthcare/HCMC, Minneapolis, MN, USA
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, USA
| | - Richard Body
- Emergency Department, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
- Division of Cardiovascular Sciences, The University of Manchester, Manchester, UK
- Healthcare Sciences Department, Manchester Metropolitan University, Manchester, UK
| | - Nicholas L Mills
- BHF/University Centre for Cardiovascular Science and Usher Institute, University of Edinburgh, Edinburgh, UK
| | - Torbjørn Omland
- Department of Cardiology, Akershus University Hospital, Lørenskog, Norway
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Jordi Ordonez-Llanos
- Servicio de Bioquímica Clínica, Hospital de Sant Pau, Barcelona, Spain
- Foundation for the Biochemistry and Molecular Pathology, Barcelona, Spain
| | - Fred S Apple
- Department of Laboratory Medicine and Pathology, Hennepin Healthcare/HCMC, Minneapolis, MN, USA
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, USA
| |
Collapse
|
5
|
Nakano K, Sugawa S, Seimiya M, Murakami S, Yasuda K, Watanabe C, Goto H, Teshima T. Frequencies of Anti-Troponin I vs Anti-Troponin T Autoantibodies and Degrees of Interference on Troponin Assays. Lab Med 2023; 54:317-323. [PMID: 36322014 DOI: 10.1093/labmed/lmac120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023] Open
Abstract
OBJECTIVE Presence of autoantibodies against troponin I (cTnI) or T (cTnT) has been reported to interfere with troponin assays. However, the extent of the interference with the measurement has not been explored sufficiently. The aims of this study were to examine the frequencies of autoantibodies against troponin I and troponin T and how much these antibodies would affect the measurement. METHODS The study comprised 52 subjects who visited Hokkaido University Hospital with suspected ischemic heart diseases. To evaluate the presence of autoantibodies, we calculated the recoveries of cTnI or cTnT after immunoglobulin G depletion, and the distributions of peaks reactive with cTnI or cTnT by high-performance liquid chromatography were examined. RESULTS Autoantibodies against cTnI and cTnT were identified in 8 subjects (15.4%) and 1 subject (1.9%), respectively. Although the greatest difference between cTnI and cTnT was 32-fold, the distributions of cTnI-to-cTnT ratios in groups with and without anti-cTnI were not statistically different. CONCLUSION Autoantibodies against cTnI were more frequent by several fold than those against cTnT. Their presence did not significantly expand the discrepancy between cTnI and cTnT assays.
Collapse
Affiliation(s)
- Keiichi Nakano
- Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital, Sapporo, Japan
- Department of Medical Technology and Sciences, School of Health Sciences at Narita, International University of Health and Welfare, Chiba, Japan
| | | | - Masanori Seimiya
- Department of Medical Technology and Sciences, School of Health Sciences at Narita, International University of Health and Welfare, Chiba, Japan
| | | | - Keiko Yasuda
- Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital, Sapporo, Japan
| | - Chiaki Watanabe
- Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital, Sapporo, Japan
| | - Hideki Goto
- Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital, Sapporo, Japan
| | - Takanori Teshima
- Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital, Sapporo, Japan
| |
Collapse
|
6
|
Hammarsten O, Becker C, Engberg AE. Methods for analyzing positive cardiac troponin assay interference. Clin Biochem 2023; 116:24-30. [PMID: 36889375 DOI: 10.1016/j.clinbiochem.2023.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 02/28/2023] [Accepted: 03/03/2023] [Indexed: 03/08/2023]
Abstract
OBJECTIVES The cardiac damage biomarkers cardiac troponin T (cTnT) and troponin I (cTnI) are used to identify patients with myocardial infarction (MI). To make the correct clinical decisions it is important to identify false positive results due to troponin assay interference. Often interferences are caused by high-molecular weight immunocomplexes called macrotroponin that may result in false troponin elevations because of delayed troponin clearance, or heterophilic antibodies that crosslink troponin assay antibodies and generate troponin-independent signals. DESIGN & METHODS We describe and compare four methods for cTnI assay interference analysis using a protein G spin column method, gel filtration chromatography and two versions of a sucrose gradient ultracentrifugation for cTnI assay interference analysis on five patients with confirmed cTnI interference and one MI patient without cTnI interference from our troponin interference referral center. RESULTS The protein G spin column method had a high between run variability but was still able to identify all five patients with cTnI interference. The sucrose gradient ultracentrifugation methods and the gel filtration method had simlar performancec and correctly identified the immunocomplexes that caused the cTnI interference. CONCLUSIONS Our experience is that these methods are sufficient to safely confirm or exclude positive cTnI assay interference.
Collapse
Affiliation(s)
- Ola Hammarsten
- Department of Clinical Chemistry and Transfusion Medicine, Sahlgrenska Academy at University of Gothenburg, SE41345 Gothenburg, Sweden.
| | - Charlotte Becker
- Department of Clinical Chemistry and Pharmacology, Regional and University Laboratories, Region Skåne, Sweden
| | - Anna E Engberg
- Department of Clinical Chemistry and Pharmacology, Regional and University Laboratories, Region Skåne, Sweden
| |
Collapse
|
7
|
Lam L, Tse R, Gladding P, Kyle C. Effect of Macrotroponin in a Cohort of Community Patients with Elevated Cardiac Troponin. Clin Chem 2022; 68:1261-1271. [PMID: 35929566 DOI: 10.1093/clinchem/hvac118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Accepted: 06/09/2022] [Indexed: 11/13/2022]
Abstract
BACKGROUND Macrotroponin is an important cause of discrepancy between current high-sensitivity cardiac troponin (hs-cTn) assays, however, its clinical significance is unclear. This study examined the effects of macrotroponin and repeat testing by different hs-cTnI assays in a cohort of community patients with elevated hs-cTnI. METHODS The first residual serum specimen from each patient in the community admitted to hospital with elevated hs-cTnI (Siemens hs-cTnI Centaur) was retested after immunoglobulin depletion and by 5 other hs-cTn assays. Low recovery of cTnI (<40%) following immunoglobulin depletion was considered as macrotroponin. A retrospective chart review was performed for these participants. Investigator-adjudicated diagnosis served as the reference standard. RESULTS In our cohort of community patients with elevated troponin (n = 188), participants with macrotroponin (n = 99) often had a multifactorial or indeterminate myocardial injury (56% vs 25%) and were less likely to have acute coronary syndrome (9% vs 28%). On repeat testing of cTn on other platforms, better diagnostic performance (c-statistics) for ischemic and non-ischemic cardiac causes was observed on the Beckman Access hs-cTnI (0.74; 95% confidence interval [CI] 0.67-0.81) or the Abbott hs-cTnI Architect (0.75; CI 0.68-0.82) compared to the Siemens hs-cTnI Vista (0.62; CI 0.54-0.70; P < 0.05). This could be attributed to differences in assay reactivity for macrotroponin. Interestingly, better diagnostic performance was observed in patients without macrotroponin. Although a small number of deaths occurred (n = 16), participants with macrotroponin had better overall survival. CONCLUSIONS In the low-risk setting, the presence of macrotroponin was clinically associated with multifactorial or indeterminate causes of troponin elevation.
Collapse
Affiliation(s)
- Leo Lam
- Chemical Pathology, LabPlus, Auckland City Hospital, Auckland, New Zealand.,Biochemistry, Middlemore Hospital Laboratories, Auckland, New Zealand
| | - Rexson Tse
- Forensic Pathology, LabPlus, Auckland City Hospital, Auckland, New Zealand
| | | | - Campbell Kyle
- Chemical Pathology, LabPlus, Auckland City Hospital, Auckland, New Zealand.,Biochemistry, Labtests, Auckland, New Zealand
| |
Collapse
|
8
|
Lam L, Hammarsten O, Kyle C. Which method to detect macrotroponin? Clin Chem Lab Med 2022; 60:68-70. [PMID: 35007413 DOI: 10.1515/cclm-2021-1330] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Accepted: 12/29/2021] [Indexed: 11/15/2022]
Affiliation(s)
- Leo Lam
- Department of Chemical Pathology, LabPLUS, Auckland City Hospital, Auckland, New Zealand.,Biochemistry Department, Middlemore Hospital Laboratories, Middlemore Hospital, Auckland, New Zealand
| | - Ola Hammarsten
- Department of Laboratory Medicine Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden.,Department of Clinical Chemistry, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Campbell Kyle
- Department of Chemical Pathology, LabPLUS, Auckland City Hospital, Auckland, New Zealand.,Department of Biochemistry, LabTests, Auckland, New Zealand
| |
Collapse
|
9
|
Lam L, Ha L, Heron C, Chiu W, Kyle C. Identification of macrotroponin T: findings from a case report and non-reproducible troponin T results. Clin Chem Lab Med 2021; 59:1972-1980. [PMID: 34496163 DOI: 10.1515/cclm-2021-0626] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 08/24/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Macrotroponin is due to cardiac troponin (cTn) binding to endogenous cTn autoantibodies. While previous studies showed a high incidence of macrotroponin affecting cTnI assays, reports of macrotroponin T, particularly without cTnI reactivity, have been rare. Although the clinical significance of macrotroponin is not fully understood, macroenzymes and complexes are recognised to cause confusion in interpretation of laboratory results. The potential for adverse clinical consequences due to misinterpretation of affected results is very high. METHODS We describe four cases of macrotroponin T with persistently low high sensitivity cTnT (hs-cTnT) by the 9 min compared to the 18 min variant of the assay. Three cases were serendipitously identified due to the use of a lot number of Roche hs-cTnT affected by non-reproducible results, necessitating measurement of cTnT in duplicate. We identified and characterised these macrotroponin specimens by immunoglobulin depletion (Protein A and PEG precipitation), mixing studies with EDTA and recombinant cTnT. RESULTS In cases of macro-cTnT, a lower result occurred on the hs-cTnT using the 9 min compared to 18 min variant assay (ratio of 9-18 min hs-cTnT <0.80). Mixing studies with recombinant cTnT or EDTA demonstrated a difference in recovery vs. controls. One of these patients demonstrated a high molecular weight complex for cTnI and cTnT demonstrating a macrocomplex involving both cTn. This patient demonstrated a rise and fall in cTn when measured by several commercial assays consistent with genuine acute cardiac injury. CONCLUSIONS We identified several cases of macro-cTnT and described associated clinical and biochemical features.
Collapse
Affiliation(s)
- Leo Lam
- Department of Chemical Pathology, LabPLUS, Auckland City Hospital, Auckland, New Zealand.,Biochemistry Department, Middlemore Hospital Laboratories, Middlemore Hospital, Auckland, New Zealand
| | - Leah Ha
- Department of Chemical Pathology, LabPLUS, Auckland City Hospital, Auckland, New Zealand.,Biochemistry Department, Middlemore Hospital Laboratories, Middlemore Hospital, Auckland, New Zealand
| | - Campbell Heron
- Department of Chemical Pathology, LabPLUS, Auckland City Hospital, Auckland, New Zealand
| | - Weldon Chiu
- Department of Chemical Pathology, LabPLUS, Auckland City Hospital, Auckland, New Zealand.,Biochemistry Department, Middlemore Hospital Laboratories, Middlemore Hospital, Auckland, New Zealand
| | - Campbell Kyle
- Department of Chemical Pathology, LabPLUS, Auckland City Hospital, Auckland, New Zealand.,Department of Biochemistry, LabTests, Auckland, New Zealand
| |
Collapse
|