Two-hour algorithm for triage toward rule-out and rule-in of acute myocardial infarction using high-sensitivity cardiac troponin T

Am J Med. 2015 Apr;128(4):369-79.e4. doi: 10.1016/j.amjmed.2014.10.032. Epub 2014 Nov 13.


Background: High-sensitivity cardiac troponin (hs-cTn) may allow an earlier diagnosis of acute myocardial infarction (AMI).

Methods: We prospectively enrolled 1148 (derivation cohort) and 517 (external validation cohort) unselected patients presenting with suspected AMI to the emergency department. Final diagnosis was adjudicated by 2 independent cardiologists. Hs-cTnT was measured at presentation and after 2 hours. A diagnostic algorithm incorporating hs-cTnT values at presentation and absolute changes within the first 2 hours was derived.

Results: AMI was the final diagnosis in 16% of patients in the derivation and 9.1% in the validation cohort. The 2-hour algorithm developed in the derivation cohort classified 60% of patients as "rule-out," 16% as "rule-in," and 24% in the "observational-zone." Resulting sensitivity and negative predictive value (NPV) were 99.5% and 99.9%, respectively, for rule-out, and specificity and positive predictive value (PPV) were 96% and 78%, respectively, for rule-in. Applying the 2-hour triage algorithm in the external validation cohort, 78% of patients could be classified as "rule-out," 8% as "rule-in," and 14% in the "observational-zone." Resulting sensitivity and NPV were 96% and 99.5%, respectively, for rule-out, and specificity and PPV were 99% and 85%, respectively, for rule-in. Cumulative 30-day survival rates were 100%, 98.9%, and 95.2% (P < .001), and 100%, 100%, and 95% (P < .001) in patients classified as "rule-out," "observational-zone," and "rule-in" in the 2 cohorts, respectively.

Conclusions: A simple algorithm incorporating hs-cTnT baseline values and absolute changes over 2 hours allowed a triage toward safe rule-out, or accurate rule-in, of AMI in the vast majority of patients, with only 20% requiring more prolonged monitoring and serial blood sampling.

Keywords: Acute myocardial infarction; Diagnostic algorithm; High-sensitive troponin.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Aged
  • Aged, 80 and over
  • Algorithms*
  • Angina Pectoris / etiology
  • Biomarkers / blood
  • Chest Pain / etiology*
  • Diagnosis, Differential
  • Early Diagnosis
  • Female
  • Humans
  • Kaplan-Meier Estimate
  • Male
  • Middle Aged
  • Myocardial Infarction / blood*
  • Myocardial Infarction / diagnosis*
  • Myocardial Infarction / mortality
  • Predictive Value of Tests
  • Prospective Studies
  • Risk Factors
  • Sensitivity and Specificity
  • Time Factors
  • Triage / methods*
  • Troponin T / blood*


  • Biomarkers
  • Troponin T