title: Early diagnosis of myocardial infarction using absolute and relative changes in cardiac troponin concentrations.
abstract: BACKGROUND
  Absolute changes in high-sensitivity cardiac troponin T (hs-cTnT) seem to have higher diagnostic accuracy in the early diagnosis of acute myocardial infarction compared with relative changes. It is unknown whether the same applies to high-sensitivity cardiac troponin I (hs-cTnI) assays and whether the combination of absolute and relative change might further increase accuracy.
  
  
  METHODS
  In a prospective, international multicenter study, high-sensitivity cardiac troponin (hs-cTn) was measured with 3 novel assays (hs-cTnT, Roche Diagnostics Corp, Indianapolis, Ind; hs-cTnI, Beckman Coulter Inc, Brea, Calif; hs-cTnI, Siemens, Munich, Germany) in a blinded fashion at presentation and after 1 and 2 hours in a blinded fashion in 830 unselected patients with suspected acute myocardial infarction. The final diagnosis was adjudicated by 2 independent cardiologists.
  
  
  RESULTS
  The area under the receiver operating characteristic curve for diagnosing acute myocardial infarction was significantly higher for 1- and 2-hour absolute versus relative hs-cTn changes for all 3 assays (P < .001). The area under the receiver operating characteristic curve of the combination of 2-hour absolute and relative change (hs-cTnT 0.98 [95% confidence interval {CI}, 0.97-0.99]; hs-cTnI, Beckman Coulter Inc, 0.97 [95% CI, 0.96-0.99]; hs-cTnI, Siemens, 0.96 [95% CI, 0.93-0.99]) were high and provided some benefit compared with the use of absolute change alone for hs-cTnT, but not for the hs-cTnI assays. Reclassification analysis confirmed the superiority of absolute changes versus relative changes.
  
  
  CONCLUSIONS
  Absolute changes seem to be the preferred metrics for both hs-cTnT and hs-cTnI in the early diagnosis of acute myocardial infarction. The combination of absolute and relative changes provides a small added value for hs-cTnT, but not for hs-cTnI.
authors.affiliation: Department of Cardiology, University Hospital Basel, Switzerland.
authors.forename: Affan
authors.initials: A
authors.lastname: Irfan
authors.forename: Tobias
authors.initials: T
authors.lastname: Reichlin
authors.forename: Raphael
authors.initials: R
authors.lastname: Twerenbold
authors.forename: Marc
authors.initials: M
authors.lastname: Meister
authors.forename: Berit
authors.initials: B
authors.lastname: Moehring
authors.forename: Karin
authors.initials: K
authors.lastname: Wildi
authors.forename: Stefano
authors.initials: S
authors.lastname: Bassetti
authors.forename: Christa
authors.initials: C
authors.lastname: Zellweger
authors.forename: Maria Rubini
authors.initials: MR
authors.lastname: Gimenez
authors.forename: Rebeca
authors.initials: R
authors.lastname: Hoeller
authors.forename: Karsten
authors.initials: K
authors.lastname: Murray
authors.forename: Seoung Mann
authors.initials: SM
authors.lastname: Sou
authors.forename: Mira
authors.initials: M
authors.lastname: Mueller
authors.forename: Tamina
authors.initials: T
authors.lastname: Mosimann
authors.forename: Miriam
authors.initials: M
authors.lastname: Reiter
authors.forename: Philip
authors.initials: P
authors.lastname: Haaf
authors.forename: Ronny
authors.initials: R
authors.lastname: Ziller
authors.forename: Heike
authors.initials: H
authors.lastname: Freidank
authors.forename: Stefan
authors.initials: S
authors.lastname: Osswald
authors.forename: Christian
authors.initials: C
authors.lastname: Mueller
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D003937:Diagnosis, Differential; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood*; D011446:Prospective Studies; D012372:ROC Curve; D019210:Troponin I / Q000097:blood*; D020107:Troponin T / Q000097:blood*
chemical_list: D019210:Troponin I; D020107:Troponin T
keywords: Absolute; Diagnosis; Myocardial infarction; Relative troponin changes