title: Diagnostic performance of cardiac Troponin I for early rule-in and rule-out of acute myocardial infarction: Results of a prospective multicenter trial.
abstract: OBJECTIVE
  To compare emergency department TnI serial sampling intervals, determine optimal diagnostic thresholds, and report representative diagnostic performance characteristics for early rule-in and rule-out of MI.
  
  
  METHODS
  We prospectively measured TnI (AccuTnI+3™, Beckman Coulter) at serial time intervals in 1929 subjects with chest pain or equivalent ischemic symptoms suggestive of acute coronary syndromes at 14 medical centers. Diagnosis was adjudicated by an independent central committee.
  
  
  RESULTS
  TnI ≥0.03ng/mL provided 96.0% sensitivity and 89.4% specificity at 1-3h after admission, and 94.9% sensitivity and 86.7% specificity at 3-6h. NPV (rule-out, non-MI) was 99.5% at 1-3h, and 99.0% at 3-6h when TnI is <0.03ng/mL. NPV was 99.1% when TnI is <0.03ng/mL and time of symptom onset is ≥8h. Approximately 50-58% (PPV) of patients with TnI ≥0.03ng/mL were diagnosed with MI, depending upon time from onset or admission; PPVs emphasize the importance of serial samples and delta TnI (rising or falling pattern) when low cutoffs are used. Nevertheless, even a single elevated TnI value increased the risk of MI. As TnI values rose, the probability of MI increased. Values ≥0.20ng/mL were associated with nearly 90% probability of MI.
  
  
  CONCLUSIONS
  We report a large multicenter prospective adjudicated trial assessing troponin for early rule-in and rule-out using the Universal Definition of MI and conducted in primary care hospital-associated emergency departments. Our study demonstrates high diagnostic accuracy at early observation times, and reinforces consensus recommendations for sampling on admission and 3h later, repeated at 6h when clinical suspicion remains high.
authors.affiliation: Dept. of Emergency Medicine, Vanderbilt University Medical Center, Nashville, TN, USA. Electronic address: alan.storrow@vanderbilt.edu.
authors.forename: Alan B
authors.initials: AB
authors.lastname: Storrow
authors.affiliation: Dept. of Pathology, University of Maryland Medical Center, Baltimore, MD, USA.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Christenson
authors.affiliation: Dept. of Emergency Medicine, Henry Ford Health System, Detroit, MI, USA.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Nowak
authors.affiliation: Dept. of Emergency Medicine, University of California Davis, Sacramento, CA, USA.
authors.forename: Deborah B
authors.initials: DB
authors.lastname: Diercks
authors.affiliation: Dept. of Emergency Medicine, State University of New York at Stony Brook, Stony Brook, NY, USA.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Singer
authors.affiliation: Clinical Chemistry Laboratory, San Francisco General Hospital, University of California, San Francisco, CA, USA.
authors.forename: Alan H B
authors.initials: AH
authors.lastname: Wu
authors.affiliation: Dept. of Emergency Medicine, Advocate Christ Medical Center, Oak Lawn, IL, USA.
authors.forename: Erik
authors.initials: E
authors.lastname: Kulstad
authors.affiliation: Dept. of Emergency Medicine, Maricopa Medical Center, Phoenix, AZ, USA.
authors.forename: Frank
authors.initials: F
authors.lastname: LoVecchio
authors.affiliation: Dept. of Emergency Medicine, Maimonides Medical Center, Brooklyn, NY, USA.
authors.forename: Christian
authors.initials: C
authors.lastname: Fromm
authors.affiliation: Chest Pain Center, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Gary
authors.initials: G
authors.lastname: Headden
authors.affiliation: Dept. of Emergency Medicine, Covenant Medical Center, Saginaw, MI, USA.
authors.forename: Tracie
authors.initials: T
authors.lastname: Potis
authors.affiliation: Dept. of Emergency Medicine, Virginia Commonwealth University Medical Center, Richmond, VA, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Hogan
authors.affiliation: Dept. of Emergency Medicine, Case Western Reserve University School of Medicine, MetroHealth Medical Center, Cleveland, OH, USA.
authors.forename: Jon W
authors.initials: JW
authors.lastname: Schrock
authors.affiliation: Dept. of Emergency Medicine, The Ohio State University Medical Center, Columbus, OH, USA.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Zelinski
authors.affiliation: Dept. of Emergency Medicine, Lehigh Valley Health Network, Allentown, PA, USA.
authors.forename: Marna R
authors.initials: MR
authors.lastname: Greenberg
authors.affiliation: Dept. of Pathology and Laboratory Medicine, Emory University, Atlanta, GA, USA.
authors.forename: James C
authors.initials: JC
authors.lastname: Ritchie
authors.affiliation: Dept. of Clinical Research, Beckman Coulter, Inc., Carlsbad, CA, USA.
authors.forename: Janna S
authors.initials: JS
authors.lastname: Chamberlin
authors.affiliation: Dept. of Clinical Research, Beckman Coulter, Inc., Carlsbad, CA, USA.
authors.forename: Kurtis R
authors.initials: KR
authors.lastname: Bray
authors.affiliation: Dept. of Clinical Research, Beckman Coulter, Inc., Carlsbad, CA, USA.
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Rhodes
authors.affiliation: Dept. of Clinical Research, Beckman Coulter, Inc., Carlsbad, CA, USA.
authors.forename: Deirdre
authors.initials: D
authors.lastname: Trainor
authors.affiliation: Dept. of Clinical Research, Beckman Coulter, Inc., Carlsbad, CA, USA.
authors.forename: Dawn
authors.initials: D
authors.lastname: Holmes
authors.affiliation: Dept. of Clinical Research, Beckman Coulter, Inc., Carlsbad, CA, USA.
authors.forename: Paula C
authors.initials: PC
authors.lastname: Southwick
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000175:diagnosis*; D011446:Prospective Studies; D019210:Troponin I / Q000097:blood*
chemical_list: D015415:Biomarkers; D019210:Troponin I
keywords: Acute coronary syndromes; Biomarkers; Chest pain; Diagnosis; Emergency medicine; Myocardial infarction; Troponin