Cardiac troponin: A critical review of the case for point-of-care testing in the ED
The measurement of cardiac troponin concentrations in the blood is a key element in the evaluation of patients with suspected acute coronary syndromes, according to current guidelines, and contributes importantly to the ruling in or ruling out of acute myocardial infarction. The introduction of point-of-care testing for cardiac troponin has the potential to reduce turnaround time for assay results, compared with central laboratory testing, optimizing resource use. Although, in general, many point-of-care cardiac troponin tests are less sensitive than cardiac troponin tests developed for central laboratory-automated analyzers, point-of-care systems have been used successfully within accelerated protocols for the reliable ruling out of acute coronary syndromes, without increasing subsequent readmission rates for this condition. The impact of shortened assay turnaround times with point-of-care technology on length of stay in the emergency department has been limited to date, with most randomized evaluations of this technology having demonstrated little or no reduction in this outcome parameter. Accordingly, the point-of-care approach has not been shown to be cost-effective relative to central laboratory testing. Modeling studies suggest, however, that reengineering overall procedures within the emergency department setting, to take full advantage of reduced therapeutic turnaround time, has the potential to improve the flow of patients through the emergency department, to shorten discharge times, and to reduce cost. To properly evaluate the potential contribution of point-of-care technology in the emergency department, including its cost-effectiveness, future evaluations of point-of-care platforms will need to be embedded completely within a local decision-making structure designed for its use.
Available from: Monique Dehoux
- "Point-of-care assays are generally run on whole blood, which means the test will not pick up any sample haemolysis or dilution effects if the result is very high. Furthermore, the C. Chenevier-Gobeaux et al. detection and measurement ranges are narrow compared with assays done on central laboratory-based analysers . "
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ABSTRACT: Cardiac troponin (cTn) assays have quickly gained in analytical sensitivity to become what are termed 'high-sensitivity cardiac troponin' (hs-cTn) assays, bringing a flurry of dense yet incomplete literature data. The net result is that cTn assays are not yet standardized and there are still no consensus-built data on how to use and interpret cTn assay results. To address these issues, the authors take cues and clues from multiple disciplines to bring responses to frequently asked questions. In brief, the effective use of hs-cTn hinges on knowing: specific assay characteristics, particularly precision at the 99th percentile of a reference population; factors of variation at the 99th percentile value; and the high-individuality of hs-cTn assays, for which the notion of individual kinetics is more informative than straight reference to 'normal' values. The significance of patterns of change between two assay measurements has not yet been documented for every hs-cTn assay. Clinicians need to work hand-in-hand with medical biologists to better understand how to use hs-cTn assays in routine practice.
Copyright © 2014 Elsevier Masson SAS. All rights reserved.
Archives of Cardiovascular Diseases 02/2015; 108(2). DOI:10.1016/j.acvd.2014.11.001 · 1.84 Impact Factor
Available from: Peter Myles George
- "In New Zealand the national Shorter Stays in ED Health Target aims for disposition of 95% of ED patients at ≤ 6 h and similar policies are under implementation internationally. Turnaround times from blood sampling to results can therefore be highly important both to meet policy targets and for efficient patient disposition and initiation of definitive treatment . Previous studies have had varying results regarding the effect of POC devices on length of stay with some showing improvement and some not [11,17,20–23]. "
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The aim of this study is to compare a new improved point of care cardiac troponin assay (new POC-cTnI) with 1. its predecessor (old POC-cTnI) and 2. a high sensitivity assay (hs-cTnI) for the diagnosis of acute myocardial infarction (AMI) and for major adverse cardiac events (MACE) by 30 days.
This is a single centre observational study, set in Christchurch Hospital, New Zealand. Patients presenting to the emergency department with non-traumatic chest pain underwent blood sampling at 0 h and 2 h post presentation for analysis with the 3 cTnI assays for the outcome of AMI and for analysis using an accelerated diagnostic protocol (ADP-normal 2 h troponins, normal electrocardiograms and Thrombolysis In Myocardial Infarction (TIMI) score of 0 or ≤ 1) for 30 day MACE.
Of 962 patients, 220 (22.9%) had AMI. Old POC-cTnI was least sensitive at 70.0% (65.4–73.9%) by 2 h (p < 0.001). New POC-cTnI, sensitivity 93.6% (89.9–96.2%) had similar sensitivity to hs-cTnI, sensitivity 95.0% (91.5–97.3%) (p = 0.508). There were 231 (24.0%) patients with 30 day MACE. When used as part of the ADP, all assays had 100% (98.0–100%) sensitivity using TIMI = 0. Sensitivities of new POC-cTnI ADP, 98.3% (95.4–99.4%), old POC-cTnI, 96.5% (93.2–98.4%) and hs-cTnI, 98.7% (96.0–99.7%) were similar (p = 0.063–0.375) using TIMI ≤ 1.
A new POC-cTnI has improved sensitivity for AMI and MACE compared with its predecessor and comparable sensitivity to a high sensitivity assay. Now that sensitivities of the POC assay are improved, the new assay may be a useful alternative to central laboratory assays when rapid turn-around times are not possible.
International Journal of Cardiology 11/2014; 177(1):182–186. DOI:10.1016/j.ijcard.2014.09.026 · 4.04 Impact Factor
Available from: Margarita E Pena
- "Guidelines and recommendations by the American Heart Association, the American College of Cardiology, and the Society of Cardiovascular Patient Care (SCPC) were discussed and incorporated into the process improvement measures    . Specifically, the triage guidelines used by nursing during the pilot and thereafter followed ACC/AHA recommendations . Process improvement suggestions concerning biomarker TAT from the Society of Cardiovascular Patient Care chest pain center accreditation tool that promotes multidisciplinary collaboration was used as an overall guide. "
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ABSTRACT: To implement collaborative process improvement measures to reduce emergency department (ED) troponin turnaround time (TAT) to less than 60 min using central laboratory.Design and methodsThis was an observational, retrospective data study. A multidisciplinary team from the ED and laboratory identified opportunities and developed a new workflow model. Process changes were implemented in ED patient triage, staffing, lab collection and processing. Data collected included TAT of door-to-order, order-to-collect, collect-to-received, received-to-result, door-to-result, ED length of stay, and hemolysis rate before (January–August, 2011) and after (September 2011–June 2013) process improvement.ResultsAfter process improvement and implementation of the new workflow model, decreased median TAT (in min) was seen in door-to-order (54 [IQR43] vs. 11 [IQR20]), order-to-collect (15 [IQR 23] vs. 10 [IQR12]), collect-to-received (6 [IQR8] vs. 5 [IQR5]), received-to-result (30 [IQR12] vs. 24 [IQR11]), and overall door-to-result (117 [IQR60] vs. 60 [IQR40]). A troponin TAT of < 60 min was realized beginning in May 2012 (59 [IQR39]). Hemolysis rates decreased (14.63 ± 0.74 vs. 3.36 ± 1.99, p < 0.0001), as did ED length of stay (5.87 ± 2.73 h vs. 5.15 ± 2.34 h, p < 0.0001). Conclusion Troponin TAT of < 60 min using a central laboratory was achieved with collaboration between the ED and the laboratory; additional findings include a decreased ED length of stay.
Clinical Biochemistry 11/2014; DOI:10.1016/j.clinbiochem.2014.10.014 · 2.28 Impact Factor
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