title: Serial changes in high-sensitivity cardiac troponin I in the early diagnosis of acute myocardial infarction.
abstract: BACKGROUND
  Current guidelines require a change (rise and/or fall) in levels of cardiac troponin (cTn) for the diagnosis of acute myocardial infarction (AMI). It is unknown whether absolute or relative changes provide higher accuracy when using high-sensitivity cTnI assays.
  
  
  METHODS
  In a prospective international multicentre study, we assessed the diagnostic accuracy of early absolute and relative changes in cTnI measured with two novel pre-commercial high-sensitivity assays (Siemens and Beckman Coulter) in 943 unselected patients presenting to the ED with suspected AMI. The final diagnosis of AMI was adjudicated using all available data including serial hs-cTnT levels by two independent cardiologists.
  
  
  RESULTS
  The diagnostic accuracy of absolute changes in the diagnosis of AMI as quantified by the area under the receiver operating characteristics curve (AUC) was very high (e.g. at 2 h, Siemens high-sensitivity cTnI AUC 0.93, 95%Cl 0.90-0.96; Beckman Coulter high-sensitivity cTnI AUC 0.93, 95%Cl 0.90-0.96) and superior to relative changes at all time points (p < 0.001). The results were consistent in clinically important subgroups. Direct comparison of the absolute changes in the two high-sensitivity cTnI assays showed similar accuracy. When combined with the baseline cTnI levels, the difference between absolute and relative changes became much smaller and remained statistically significant only for the Siemens assay.
  
  
  CONCLUSIONS
  As single variables early absolute changes in high-sensitivity cTnI levels have significantly higher diagnostic accuracy than relative changes. When combined with the baseline cTn level, reflecting clinical practice, both absolute and relative changes provided very high accuracy with much smaller differences between both approaches.
authors.affiliation: Department of Cardiology, University Hospital Basel, Switzerland; Department of Internal Medicine, University Hospital, Basel, Switzerland.
authors.forename: Karin
authors.initials: K
authors.lastname: Wildi
authors.forename: Tobias
authors.initials: T
authors.lastname: Reichlin
authors.forename: Raphael
authors.initials: R
authors.lastname: Twerenbold
authors.forename: Fabienne
authors.initials: F
authors.lastname: Mäder
authors.forename: Christa
authors.initials: C
authors.lastname: Zellweger
authors.forename: Berit
authors.initials: B
authors.lastname: Moehring
authors.forename: Fabio
authors.initials: F
authors.lastname: Stallone
authors.forename: Jan
authors.initials: J
authors.lastname: Minners
authors.forename: Maria
authors.initials: M
authors.lastname: Rubini 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: Kris
authors.initials: K
authors.lastname: Denhaerynck
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: Bernadette
authors.initials: B
authors.lastname: Meller
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; D015415:Biomarkers / Q000097:blood; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D038622:Internationality; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000175:diagnosis*; D011446:Prospective Studies; D013997:Time Factors; D019210:Troponin I / Q000097:blood*
chemical_list: D015415:Biomarkers; D019210:Troponin I
keywords: Absolute and relative changes; Diagnosis of acute myocardial infarction; High-sensitivity troponin I