title: Using high-sensitivity troponin T: the importance of the proper gold standard.
abstract: OBJECTIVE
  The study objective was to determine how best to use high-sensitivity cardiac troponin T (hscTnT) to diagnose myocardial infarction.
  
  
  METHODS
  A total of 358 patients presenting with acute coronary syndromes sampled at admission and 2, 4, and 6 to 8 hours. Both contemporary cardiac troponin T (cTnT) and hscTnT were measured. Patients were classified with conventional cTnT values by independent investigators. Myocardial infarction required a cTnT value ≥99th reference percentile and a ≥20% change.
  
  
  RESULTS
  Seventy-nine patients had non-ST-segment elevation myocardial infarction, 105 patients had unstable angina, and 174 patients had nonacute coronary syndromes. A cTnT cutoff at the 10% coefficient of variation value missed 14.5% of infarctions. hscTnT had a sensitivity at admission of 89.9%, but specificity was only 75.1% because of elevations in 45.3% and 25.3% of those with unstable angina and nonacute coronary syndromes, respectively. The optimal value for myocardial infarction diagnosis with hscTnT was 25 ng/L at admission and 30 ng/L during serial sampling. All infarctions were diagnosed within 4 hours, with a time saving of 11 and 68 minutes compared with a cTnT value at the 99th reference percentile value and a cTnT value at a coefficient of variation of 10%. By using the 99th percentile of hsTnT plus a ≥20% change, 25 additional infarctions were identified. With these included, the optimal cutoff decreased to 12 ng/L at admission and 13 ng/L over time, but time to diagnosis increased.
  
  
  CONCLUSIONS
  The gold standard used to diagnose myocardial infarction makes a major difference in the results. When myocardial infarction is diagnosed using hscTnT 99th percentile values with a 20% change, more are identified, diagnosis is delayed, and the optimal value for use is reduced.
authors.affiliation: Hospital Sant Pau, Barcelona, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Santaló
authors.forename: Alfonso
authors.initials: A
authors.lastname: Martin
authors.forename: Joaquin
authors.initials: J
authors.lastname: Velilla
authors.forename: Juan
authors.initials: J
authors.lastname: Povar
authors.forename: Francisco
authors.initials: F
authors.lastname: Temboury
authors.forename: Jose
authors.initials: J
authors.lastname: Balaguer
authors.forename: Mar
authors.initials: M
authors.lastname: Muñoz
authors.forename: Pilar
authors.initials: P
authors.lastname: Calmarza
authors.forename: Carmen
authors.initials: C
authors.lastname: Ortiz
authors.forename: Arturo
authors.initials: A
authors.lastname: Carratalá
authors.forename: Ignacio
authors.initials: I
authors.lastname: Gich
authors.forename: Javier
authors.initials: J
authors.lastname: Mercé
authors.forename: Allan S
authors.initials: AS
authors.lastname: Jaffe
authors.forename: Jordi
authors.initials: J
authors.lastname: Ordoñez-Llanos
mesh_terms: D054058:Acute Coronary Syndrome / Q000097:blood* / Q000175:diagnosis; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000789:Angina, Unstable / Q000097:blood / Q000175:diagnosis; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000175:diagnosis; D011446:Prospective Studies; D012016:Reference Values; D012680:Sensitivity and Specificity; D013997:Time Factors; D020107:Troponin T / Q000097:blood*
chemical_list: D020107:Troponin T
keywords: High-sensitivity troponin T; Non-ST-segment elevation myocardial infarction