title: The Use of Very Low Concentrations of High-sensitivity Troponin T to Rule Out Acute Myocardial Infarction Using a Single Blood Test.
abstract: Recent single-center and retrospective studies suggest that acute myocardial infarction (AMI) could be immediately excluded without serial sampling in patients with initial high-sensitivity cardiac troponin T (hs-cTnT) levels below the limit of detection (LoD) of the assay and no electrocardiogram (ECG) ischemia.
  
  
  
  We aimed to determine the external validity of those findings in a multicenter study at 12 sites in nine countries.
  
  
  
  TRAPID-AMI was a prospective diagnostic cohort study including patients with suspected cardiac chest pain within 6 hours of peak symptoms. Blood drawn on arrival was centrally tested for hs-cTnT (Roche; 99th percentile = 14 ng/L, LoD = 5 ng/L). All patients underwent serial troponin sampling over 4-14 hours. The primary outcome, prevalent AMI, was adjudicated based on sensitive troponin I (Siemens Ultra) levels. Major adverse cardiac events (MACE) including AMI, death, or rehospitalization for acute coronary syndrome with coronary revascularization were determined after 30 days.
  
  
  
  We included 1,282 patients, of whom 213 (16.6%) had AMI and 231 (18.0%) developed MACE. Of 560 (43.7%) patients with initial hs-cTnT levels below the LoD, four (0.7%) had AMI. In total, 471 (36.7%) patients had both initial hs-cTnT levels below the LoD and no ECG ischemia. These patients had a 0.4% (n = 2) probability of AMI, giving 99.1% (95% confidence interval [CI] = 96.7% to 99.9%) sensitivity and 99.6% (95% CI = 98.5% to 100.0%) negative predictive value. The incidence of MACE in this group was 1.3% (95% CI = 0.5% to 2.8%).
  
  
  
  In the absence of ECG ischemia, the detection of very low concentrations of hs-cTnT at admission seems to allow rapid, safe exclusion of AMI in one-third of patients without serial sampling. This could be used alongside careful clinical assessment to help reduce unnecessary hospital admissions.
authors.affiliation: Emergency Department, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. richard.body@manchester.ac.uk.|Cardiovascular Sciences Research Group, University of Manchester, Oxford Road, Manchester, United Kingdom. richard.body@manchester.ac.uk.
authors.forename: Richard
authors.initials: R
authors.lastname: Body
authors.affiliation: Department of Cardiology, Universitätsspital Basel, Basel, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Mueller
authors.affiliation: Abteilung Innere Medizin III Kardiologie, Angiologie und Pneumologie, Medizinische Universitätsklinik (Krehl-Linik), Heidelberg, Germany.
authors.forename: Evangelos
authors.initials: E
authors.lastname: Giannitsis
authors.affiliation: Klinik für Notfallmedizin und Internistische Intensivmedizine, Klinikum Nürnberg Nord, Nürnberg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Christ
authors.affiliation: IIB-Hospital de la Santa Creu i Sant Pau and Universitat Autònoma, Barcelona, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Ordonez-Llanos
authors.affiliation: Division of Cardiology, University of Maryland, Baltimore, MD.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: de Filippi
authors.affiliation: Henry Ford West Bloomfield Hospital, West Bloomfield, MI.
authors.forename: Richard
authors.initials: R
authors.lastname: Nowak
authors.affiliation: Azienda Ospedaliera Luigi Sacco Laboratorio Analisi Chimico Cliniche, Milan, Italy.
authors.forename: Mauro
authors.initials: M
authors.lastname: Panteghini
authors.affiliation: Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Tomas
authors.initials: T
authors.lastname: Jernberg
authors.affiliation: Servizio Medicina di Laboratorio Azienda Ospedaliera, Università di Padova Via Giustinianeo, Padova, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Plebani
authors.affiliation: Department of Acute Medicine, Cliniques Universitaires St-Luc, Université Catholique de Louvain, Brussels, Belgium.
authors.forename: Franck
authors.initials: F
authors.lastname: Verschuren
authors.affiliation: Department of Cardiology, Liverpool Hospital, Liverpool, New South Wales, Australia.
authors.forename: John K
authors.initials: JK
authors.lastname: French
authors.affiliation: University of Maryland School of Medicine, Baltimore, MD.
authors.forename: Robert
authors.initials: R
authors.lastname: Christenson
authors.affiliation: Roche Diagnostics Germany, Penzberg, Germany.
authors.forename: Silvia
authors.initials: S
authors.lastname: Weiser
authors.affiliation: Roche Diagnostics Germany, Penzberg, Germany.
authors.forename: Garnet
authors.initials: G
authors.lastname: Bendig
authors.affiliation: Roche Diagnostics Germany, Penzberg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Dilba
authors.affiliation: Department of Medical Sciences and Uppsala Clinical Research Center, Uppsala University, Uppsala, Sweden.
authors.forename: Bertil
authors.initials: B
authors.lastname: Lindahl
mesh_terms: D054058:Acute Coronary Syndrome / Q000150:complications; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002637:Chest Pain / Q000209:etiology*; D015331:Cohort Studies; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis*; D011446:Prospective Studies; D012189:Retrospective Studies; D019210:Troponin I / Q000097:blood; D020107:Troponin T / Q000097:blood*
chemical_list: D015415:Biomarkers; D019210:Troponin I; D020107:Troponin T