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El-Khoury JM. Laboratory-developed tests: The forgotten majority. Am J Clin Pathol 2023; 160:541. [PMID: 37449363 DOI: 10.1093/ajcp/aqad080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 06/22/2023] [Indexed: 07/18/2023] Open
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Malaeb H, Vera MA, Sangal RB, Venkatesh AK, Possick S, Maciejak L, Oberle E, El-Khoury JM. Rapid serum tubes reduce transport hemolysis and false positive rates for high-sensitivity troponin T. Clin Chim Acta 2023; 551:117630. [PMID: 38420909 DOI: 10.1016/j.cca.2023.117630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 10/31/2023] [Accepted: 11/03/2023] [Indexed: 11/08/2023]
Abstract
INTRODUCTION Hemolysis in the emergency department (ED) can significantly delay results and appropriate action. We evaluated the main sources of hemolysis during sample collection, and to evaluate the use of rapid serum tubes (RST) as a transport hemolysis-mitigating measure for high-sensitivity troponin T (hs-cTnT) testing. METHODS We examined the effect of tube type, tube fill, types of sample draw and collection methods on hemolysis and hs-cTnT in samples (n = 158) from ED patients. We also compared hs-cTnT values in paired RST and plasma separate tube (PST) samples that were hemolysis-free. RESULTS The primary source of hemolysis in samples collected in the ED was underfilling tubes. In both tube types, PST and RST, filled tubes showed a median reduction in hemolysis of 69.1 % (p < 0.0001). Blood collected in RST also experienced less hemolysis compared to PST. In hemolysis-free samples, false positive results in PST were noted in patients with hs-cTnT values < 50 ng/l. CONCLUSION We suggest that proper tube filling during sample collection and use of RST tubes can significantly reduce the effects of hemolysis. In addition, laboratories should be aware that PST tubes have a non-trivial rate of false positives when hs-cTnT < 50 ng/l.
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Affiliation(s)
- Hind Malaeb
- Departments of Laboratory Medicine, Yale School of Medicine, New Haven, CT, United States
| | - Michael A Vera
- Departments of Laboratory Medicine, Yale School of Medicine, New Haven, CT, United States
| | - Rohit B Sangal
- Departments of Emergency Medicine, Yale School of Medicine, New Haven, CT, United States
| | - Arjun K Venkatesh
- Departments of Emergency Medicine, Yale School of Medicine, New Haven, CT, United States
| | - Stephen Possick
- Departments of Cardiology, Yale School of Medicine, New Haven, CT, United States
| | - Lisa Maciejak
- Departments of Emergency Medicine, Yale School of Medicine, New Haven, CT, United States
| | - Erica Oberle
- Departments of Emergency Medicine, Yale School of Medicine, New Haven, CT, United States
| | - Joe M El-Khoury
- Departments of Laboratory Medicine, Yale School of Medicine, New Haven, CT, United States.
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Suh EH, Probst MA, Tichter AM, Ranard LS, Amaranto A, Chang BC, Huynh PA, Kratz A, Lee RJ, Rabbani LE, Sacco DL, Einstein AJ. Flexible-Interval High-Sensitivity Troponin Velocity for the Detection of Acute Coronary Syndromes. Am J Cardiol 2023; 203:240-247. [PMID: 37506670 DOI: 10.1016/j.amjcard.2023.06.080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 06/14/2023] [Accepted: 06/24/2023] [Indexed: 07/30/2023]
Abstract
Many algorithms for emergency department (ED) evaluation of acute coronary syndrome (ACS) using high-sensitivity troponin assays rely on the detection of a "delta," the difference in concentration over a predetermined interval, but collecting specimens at specific times can be difficult in the ED. We evaluate the use of troponin "velocity," the rate of change of troponin concentration over a flexible short interval for the prediction of major adverse cardiac events (MACEs) at 30 days. We conducted a prospective, observational study on a convenience sample of 821 patients who underwent ACS evaluation at a high-volume, urban ED. We determined the diagnostic performance of a novel velocity-based algorithm and compared the performance of 1- and 2-hour algorithms adapted from the European Society of Cardiology (ESC) using delta versus velocity. A total of 7 of 332 patients (2.1%) classified as low risk by the velocity-based algorithm experienced a MACE by 30 days compared with 35 of 221 (13.8%) of patients classified as greater than low risk, yielding a sensitivity of 83.3% (95% confidence interval [CI] 68.6% to 93.0%) and negative predictive value (NPV) of 97.9% (95% CI 95.9% to 98.9%). The ESC-derived algorithms using delta or velocity had NPVs ranging from 98.4% (95% CI 96.4% to 99.3%) to 99.6% (95% CI 97.0% to 99.9%) for 30-day MACEs. The NPV of the novel velocity-based algorithm for MACE at 30 days was borderline, but the substitution of troponin velocity for delta in the framework of the ESC algorithms performed well. In conclusion, specimen collection within strict time intervals may not be necessary for rapid evaluation of ACS with high-sensitivity troponin.
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Affiliation(s)
- Edward Hyun Suh
- Department of Emergency Medicine, Columbia University Irving Medical Center, New York, New York.
| | - Marc A Probst
- Department of Emergency Medicine, Columbia University Irving Medical Center, New York, New York
| | - Aleksandr M Tichter
- Department of Emergency Medicine, Baylor College of Medicine, Houston, Texas
| | - Lauren S Ranard
- Seymour, Paul, and Gloria Milstein Division of Cardiology, Columbia University Irving Medical Center, New York, New York
| | - Andrew Amaranto
- Department of Emergency Medicine, Hackensack School of Medicine, Hackensack, New Jersey
| | - Betty C Chang
- Department of Emergency Medicine, Columbia University Irving Medical Center, New York, New York
| | - Phong Anh Huynh
- Department of Emergency Medicine, Baylor College of Medicine, Houston, Texas
| | - Alexander Kratz
- Department of Pathology and Cell Biology, New York-Presbyterian Hospital, Columbia University Irving Medical Center, New York, New York
| | - Rebekah J Lee
- Stony Brook University School of Medicine, Stony Brook, New York
| | - Leroy E Rabbani
- Seymour, Paul, and Gloria Milstein Division of Cardiology, Columbia University Irving Medical Center, New York, New York
| | - Dana L Sacco
- Department of Emergency Medicine, Columbia University Irving Medical Center, New York, New York
| | - Andrew J Einstein
- Seymour, Paul, and Gloria Milstein Division of Cardiology, Columbia University Irving Medical Center, New York, New York
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Tang NY, Mitchell KR, Groboske SE, Baldwin AD, Lenza M, Yeo KTJ, van Wijk XMR. Reducing Specimen Rejection Rates Using Concentration-Dependent Hemolysis Rejection Thresholds. J Appl Lab Med 2023; 8:285-295. [PMID: 36592084 DOI: 10.1093/jalm/jfac095] [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: 06/20/2022] [Accepted: 08/22/2022] [Indexed: 01/03/2023]
Abstract
BACKGROUND Using middleware solutions, it is possible to implement concentration-dependent analyte-specific hemolysis rejection limits. This makes day-to-day reporting of clinical specimens more efficient and potentially lowers sample rejection rates compared to a "one-size-fits-all" approach (i.e., solely based on a single cutoff provided in the package insert). METHODS Hemolysis interference studies were performed at multiple analyte concentrations for three frequently ordered tests. For each assay, concentration-dependent hemolysis rejection limits were designed based on the total allowable error (TAE) for the analyte as well as the clinical significance of such incurred inaccuracy at the respective concentrations. In general, the following rationale was used: if the interference exceeds 10% (or package insert cutoffs), a comment is placed on the result. If the interference exceeds the TAE, the result will not be reported. Reduction in specimen rejection rates were estimated by comparing the incurred specimen rejection rates when package inserts' vs concentration-dependent hemolysis interference limits were applied to a data set in our institute during a three-month period. RESULTS Concentration-dependent analyte-specific hemolysis rejection thresholds were designed for three commonly ordered assays that are especially susceptible to hemolysis interference. It is estimated that these novel thresholds for aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and direct bilirubin (DBIL) reduced specimen rejection rates from 9.3% to 1.3%, 31.4% to 4.8%, and 19.9% to 7.1%, respectively. CONCLUSIONS Concentration-dependent analyte-specific hemolysis rejection thresholds for three commonly ordered assays can reduce rejection rates without significantly compromising the quality of test results.
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Affiliation(s)
- Nga Yeung Tang
- Department of Pathology, The University of Chicago, Chicago, IL.,Department of Pathology and Laboratory Medicine, Beaumont Health, Royal Oak, MI.,Department of Pathology and Laboratory Medicine, Oakland University William Beaumont School of Medicine, Auburn Hills, MI
| | - Kelly R Mitchell
- Section of Clinical Chemistry, The University of Chicago Medicine, Chicago, IL
| | - Sarah E Groboske
- Section of Clinical Chemistry, The University of Chicago Medicine, Chicago, IL
| | - Angel D Baldwin
- Section of Clinical Chemistry, The University of Chicago Medicine, Chicago, IL
| | - Michael Lenza
- Section of Clinical Chemistry, The University of Chicago Medicine, Chicago, IL
| | | | - Xander M R van Wijk
- Department of Pathology, The University of Chicago, Chicago, IL.,Medical and Scientific Affairs, Beckman Coulter, Brea, CA
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Malaeb H, Vera MA, Figueroa Villalba C, El-Khoury JM. Hemolysis or wine? A case of red-wine-colored plasma. Clin Chim Acta 2023; 542:117277. [PMID: 36870523 DOI: 10.1016/j.cca.2023.117277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/24/2023] [Accepted: 02/27/2023] [Indexed: 03/06/2023]
Affiliation(s)
- Hind Malaeb
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, CT, United States
| | - Michael A Vera
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, CT, United States
| | | | - Joe M El-Khoury
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, CT, United States.
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Donato LJ, Wockenfus AM, Katzman BM, Baumann NA, Jaffe AS, Karon BS. Analytical and Clinical Considerations in Implementing the Roche Elecsys Troponin T Gen 5 STAT Assay. Am J Clin Pathol 2021; 156:1121-1129. [PMID: 34223873 DOI: 10.1093/ajcp/aqab082] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 04/12/2021] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES To evaluate the analytical and clinical performance characteristics of the fifth-generation troponin T reagent. METHODS Troponin T was measured in 2,332 paired serum and plasma samples from emergency department and hospital patients using the fourth- and fifth-generation reagents. Testing was repeated after recentrifugation to determine the frequency of analytical outliers and percentage of patients with elevated values for each assay. We conducted separate experiments to determine the effects of biotin and hemolysis interference, as well as measure interinstrument variability, for fifth-generation troponin T. RESULTS Analytic outliers occurred more frequently using the fifth-generation reagent (3.4%) compared with the fourth-generation reagent (1.0%). The frequency of elevated troponin T above the 99th percentile upper reference limit was 26% for the fourth-generation reagent and 52% for the fifth-generation reagent. Clinically significant assay interference by biotin was observed at 20 ng/mL, but hemolysis interference was not observed until an H index of 150. Instrument-to-instrument variability between e411 and e601/602 instrument platforms is predicted to confound clinical interpretation of troponin changes. CONCLUSIONS Analytical outliers and instrument-to-instrument variability are the two analytical variables most likely to confound interpretation of changes in fifth-generation troponin T results over time.
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Affiliation(s)
- Leslie J Donato
- Departments of Laboratory Medicine and Pathology, Rochester, MN, USA
| | - Amy M Wockenfus
- Departments of Laboratory Medicine and Pathology, Rochester, MN, USA
| | - Brooke M Katzman
- Departments of Laboratory Medicine and Pathology, Rochester, MN, USA
| | - Nikola A Baumann
- Departments of Laboratory Medicine and Pathology, Rochester, MN, USA
| | - Allan S Jaffe
- Departments of Laboratory Medicine and Pathology, Rochester, MN, USA
- Cardiology, Mayo Clinic, Rochester, MN, USA
| | - Brad S Karon
- Departments of Laboratory Medicine and Pathology, Rochester, MN, USA
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Krintus M, Panteghini M. Laboratory-related issues in the measurement of cardiac troponins with highly sensitive assays. Clin Chem Lab Med 2021; 58:1773-1783. [PMID: 32134723 DOI: 10.1515/cclm-2020-0017] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 01/24/2020] [Indexed: 12/13/2022]
Abstract
A number of assay-related issues can affect the performance of cardiac troponin (cTn) measurement in everyday practice. In this respect, it is vital that all information on cTn assays is known and that the performance characteristics of assays are objectively assessed and adequately described. The advent of the latest generation of more sensitive cTn assays has heralded a new wave of information about low concentrations of cTn in blood. These recent generation assays have improved analytical sensitivity and corresponding performance at low cTn concentrations when compared to their predecessors, providing a convincing goal for laboratory medicine in helping clinicians in the diagnosis of acute myocardial infarction. Crucial to the clinical utility of highly sensitive cTn assays is the laboratorians' role in closely scrutinizing proposed assays and defining their value in relation to available evidence. Analytical, as well as pre-analytical and post-analytical, aspects must be documented. In this review, we describe what laboratory professionals should know about their cTn assay performance characteristics and the pre-analytical prerequisites for robustness to ensure optimal post-analytical reporting.
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Affiliation(s)
- Magdalena Krintus
- Department of Laboratory Medicine, Nicolaus Copernicus University, Collegium Medicum, 9 Sklodowskiej-Curie Street, 85-094 Bydgoszcz, Poland, Phone: +48 52 585 44 90, Fax: +48 52 585 36 03
| | - Mauro Panteghini
- Department of Biomedical and Clinical Sciences 'Luigi Sacco', University of Milan, Milan, Italy
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Establishing hemolysis and lipemia acceptance thresholds for clinical chemistry tests. Clin Chim Acta 2020; 510:459-465. [PMID: 32771484 DOI: 10.1016/j.cca.2020.08.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/27/2020] [Accepted: 08/04/2020] [Indexed: 11/23/2022]
Abstract
BACKGROUND A key component of laboratory medicine is the evaluation of specimen suitability for downstream analytical testing. Accurate identification and characterization of the impact of interferents on clinical chemistry analytes is important for patient care. To empirically assess the influence of hemolysis and lipemia on clinical chemistry tests analyzed on a Roche cobas® c701 system, we evaluated serum pools spiked with increasing concentrations of hemolysate and Intralipid®. METHODS Using an interferent acceptance threshold of within ± 10% of the non-hemolyzed or non-lipemic results, 31 routine chemistry analytes were evaluated. RESULTS The majority of analytes were determined to have the same or very similar acceptability thresholds as those listed in the vendor package insert. However, several analytes resulted in new thresholds that deviated from manufacturer recommendations (9 higher and 2 lower for lipemia, 7 higher and 6 lower for hemolysis). Samples with high enzyme activities (LDH, ALT, AST, ALP, and CK) were observed to tolerate higher levels of hemolysis, and tiered hemolysis thresholds were established for these enzymes. Independent evaluation of indices is recommended to enable thoughtful implementation of specimen quality criteria and to provide guidance to laboratorians and providers on the nature of these interferences.
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Tang NY, Yeo KTJ, van Wijk XMR. Evaluation of interference effects from hemolysis, icterus and lipemia on the Roche Elecsys® Anti-SARS-CoV-2 assay. Clin Chim Acta 2020; 509:293-294. [PMID: 32598879 PMCID: PMC7318977 DOI: 10.1016/j.cca.2020.06.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 06/17/2020] [Accepted: 06/23/2020] [Indexed: 11/30/2022]
Affiliation(s)
- Nga-Yeung Tang
- Department of Pathology, Pritzker School of Medicine, The University of Chicago, Chicago, IL, United States
| | - Kiang-Teck J Yeo
- Department of Pathology, Pritzker School of Medicine, The University of Chicago, Chicago, IL, United States
| | - Xander M R van Wijk
- Department of Pathology, Pritzker School of Medicine, The University of Chicago, Chicago, IL, United States.
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