Objectives The rapid turnaround time of point-of-care (POC) cardiac troponin (cTn) assays is highly attractive for crowded emergency departments (EDs). We evaluated the diagnostic accuracy of the Troponin-only Manchester Acute Coronary Syndromes (T-MACS) decision aid with a POC cTn assay.
Methods In a prospective diagnostic accuracy study at eight EDs, we included patients with suspected acute coronary syndromes (ACS). Blood drawn on arrival and 3 hours later was analysed for POC cTnI (i-Stat, Abbott Point of Care). The primary outcome was a diagnosis of ACS, which included both an adjudicated diagnosis of acute myocardial infarction (AMI) based on serial laboratory cTn testing and major adverse cardiac events (death, AMI or coronary revascularisation) within 30 days.
Results Of 716 patients included, 105 (14.7%) had ACS. Using serial POC cTnI concentrations over 3 hours could have ‘ruled out’ ACS in 198 (31.2%) patients with a sensitivity of 99.0% (95% CI 94.4% to 100.0%) and negative predictive value 99.5% (95% CI 96.5% to 99.9%). No AMIs were missed. T-MACS ‘ruled in’ ACS for 65 (10.4%) patients with a positive predictive value of 91.2% (95% CI 82.1% to 95.9%) and specificity 98.9% (97.6% to 99.6%).
Conclusion With a POC cTnI assay, T-MACS could ‘rule out’ ACS for approximately one-third of patients within 3 hours while ‘ruling in’ ACS for another 10%. The rapid turnaround time and portability of the POC assay make this an attractive pathway for use in crowded EDs or urgent care centres. Future work should also evaluate use in the prehospital environment.
- acute coronary syndromes
- clinical decision rules
- cardiac troponin
- sensitivity and specificity
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Contributors All authors contributed substantially to this work, the revision and final approval of the manuscript, and meet the ICMJE criteria for authorship.
Funding This study was funded by a research grant from Abbott Point of Care. The study was sponsored by Manchester University NHS Foundation Trust.
Competing interests RB Speaker fees from Singulex; Roche (consultancy, research grant); Abbott Point of Care (speaker fee, research grant); FABPulous BV (consultancy); Alere (donation of reagents for research).
Patient consent Obtained.
Ethics approval The study was approved by the National Research Ethics Service (reference 14/NW/1344), was sponsored by Manchester University NHS Foundation Trust and was undertaken in full compliance with the Declaration of Helsinki and according to the principles of Good Clinical Practice.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement For queries about unpublished data, please contact Professor Richard Body at email@example.com.
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