title: Diagnostic accuracy of a point-of-care troponin I assay for acute myocardial infarction within 3 hours after presentation in early presenters to the emergency department with chest pain.
abstract: BACKGROUND
  Guidelines recommend that serial cardiac marker testing to rule out acute myocardial infarction (AMI) be performed for 8 to 12 hours after symptom onset. We aim to determine the diagnostic accuracy of a contemporary point-of-care (POC) troponin I (TnI) assay within 3 hours for patients presenting within 8 hours of symptom onset.
  
  
  METHODS
  The MIDAS study collected blood from patients presenting with suspected acute coronary syndrome at presentation and at 90 minutes, 3 hours, and 6 hours in whom the emergency physician planned an objective cardiac ischemia evaluation. Criterion standard diagnoses were adjudicated by experienced clinicians using all available medical records per American Heart Association/American College of Cardiology criteria. Reviewers were blinded to the investigational marker, Cardio3 TnI POC. The Cardio3 TnI reference value was defined as >0.05 ng/mL. Measures of diagnostic accuracy are presented with 95% CI.
  
  
  RESULTS
  A total of 858 of 1107 patients met the inclusion criteria. The study cohort had 476 men (55.5%) with median age of 57.0 years (interquartile range 48.0-67.0 years). Median time from symptom onset to initial blood draw was 3.9 hours (interquartile range 2.7-5.2 hours). Acute myocardial infarction was diagnosed in 82 patients (9.6%). The sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio over 3 hours were 84.1, 93.4, 12.8, and 0.17, respectively. There was no significant improvement in diagnostic accuracy associated with adding 6-hour serial testing to the 3-hour sample.
  
  
  CONCLUSIONS
  In suspected patients with acute coronary syndrome presenting to the emergency department within 8 hours of symptom onset, 3 hours of serial testing with the Cardio3 TnI POC platform provides similar diagnostic accuracy for AMI as longer periods.
authors.affiliation: University of California, Davis, Sacramento, USA. dbdiercks@ucdavis.edu
authors.forename: Deborah B
authors.initials: DB
authors.lastname: Diercks
authors.forename: W Frank
authors.initials: WF
authors.lastname: Peacock
authors.forename: Judd E
authors.initials: JE
authors.lastname: Hollander
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Singer
authors.forename: Robert
authors.initials: R
authors.lastname: Birkhahn
authors.forename: Nathan
authors.initials: N
authors.lastname: Shapiro
authors.forename: Ted
authors.initials: T
authors.lastname: Glynn
authors.forename: Richard
authors.initials: R
authors.lastname: Nowack
authors.forename: Basmah
authors.initials: B
authors.lastname: Safdar
authors.forename: Chadwick D
authors.initials: CD
authors.lastname: Miller
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Lewandrowski
authors.forename: John T
authors.initials: JT
authors.lastname: Nagurney
mesh_terms: D000368:Aged; D000787:Angina Pectoris / Q000209:etiology; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D004636:Emergency Service, Hospital / Q000592:standards*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000150:complications / Q000175:diagnosis*; D019095:Point-of-Care Systems / Q000592:standards*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D019210:Troponin I / Q000097:blood*; D014481:United States
chemical_list: D015415:Biomarkers; D019210:Troponin I