title: Comparison of high sensitivity and contemporary troponin assays for the early detection of acute myocardial infarction in the emergency department.
abstract: BACKGROUND
  Current guidelines define acute myocardial infarction (AMI) by the rise and/or fall of cardiac troponin with ≥1 value above the 99th percentile. Past troponin assays have been unreliable at the lower end of the range. Highly sensitive assays have therefore been developed to increase the clinical sensitivity for detection of myocardial injury.
  
  
  METHODS
  Three hundred and thirty-two patients with chest pain suggestive of AMI were prospectively recruited between November 2006 and April 2007. Serial blood samples were analysed to compare Roche Elecsys high sensitivity troponin T (hsTnT), Abbott Architect troponin I 3rd generation (TnI 3) and Roche Elecsys troponin T (TnT) for the diagnosis of AMI.
  
  
  RESULTS
  One hundred and ten (33.1%) patients were diagnosed with AMI. Test performance for the diagnosis of AMI, as quantified by receiver operating characteristic area under the curve (95% confidence intervals) for baseline/follow-up troponins were as follows: hsTnT 0.90 (0.87-0.94)/0.94 (0.91-0.97), TnI 3 0.88 (0.84-0.92)/0.93 (0.90-0.96) and TnT 0.80 (0.74-0.85)/0.89 (0.85-0.94). hsTnT was superior to TnT (P < 0.001/0.013 at baseline/follow-up) but equivalent to TnI 3. For patients with a final diagnosis of AMI, baseline troponins were raised in more patients for hsTnT (83.6%) than TnI 3 (74.5%) and TnT (62.7%). A delta troponin of ≥20% increased the specificity of hsTnT from 80.6% to 93.7% but reduced sensitivity from 90.9% to 71.8%.
  
  
  CONCLUSIONS
  hsTnT was superior to TnT but equivalent to TnI 3 for the diagnosis of AMI. Serial troponin measurement increased test performance. hsTnT was the most likely to be raised at baseline in those with AMI. A delta troponin increases specificity but reduces sensitivity.
authors: Cardiology Department, Christchurch Hospital, Riccarton Road, Christchurch, New Zealand. sally.aldous@cdhb.govt.nz
authors: Sally J
authors: SJ
authors: Aldous
authors: Chris M
authors: CM
authors: Florkowski
authors: Ian G
authors: IG
authors: Crozier
authors: John
authors: J
authors: Elliott
authors: Peter
authors: P
authors: George
authors: John G
authors: JG
authors: Lainchbury
authors: Richard J
authors: RJ
authors: Mackay
authors: Martin
authors: M
authors: Than
authors: Dylan Finlay
authors: DF
authors: Flaws
authors: Jennifer
authors: J
authors: Borowsky
mesh_terms: D000368:Aged; D000789:Angina, Unstable / Q000150:complications; D042241:Early Diagnosis; D004632:Emergency Medical Services / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000150:complications / Q000175:diagnosis*; D012372:ROC Curve; D012680:Sensitivity and Specificity; D013997:Time Factors; D019210:Troponin I / Q000097:blood*; D020107:Troponin T / Q000097:blood*
chemical_list: D019210:Troponin I; D020107:Troponin T