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New and Established Troponin Assays Are Highly Sensitive and Specific for AMI

Use of either type of assay can safely exclude or confirm AMI within 3 hours of emergency department admission.

Early recognition or exclusion of acute myocardial infarction (AMI) is critical for determining which patients do or do not require additional diagnostic and therapeutic measures. In a prospective study, researchers compared the accuracy of a novel highly sensitive troponin I (hsTnI) assay (Architect STAT High Sensitivity Troponin; Abbott Diagnostics) and an established troponin I (eTnI) assay (Architect STAT) for diagnosing AMI at admission and at 3 hours. The study was partially funded by the manufacturer of the assays.

Of 1818 consecutive patients with suspected acute coronary syndrome who were enrolled at three hospitals in Germany during 2007 and 2008, 413 patients (23%) received a diagnosis of AMI; 56 patients with AMI (14%) presented with ST-segment-elevation. Using a diagnostic cutoff troponin concentration representing the 99th percentile of a reference population, hsTnI at admission had a sensitivity of 82% and a negative predictive value (NPV) of 95% for AMI, and eTnI had a sensitivity of 79% and an NPV of 94%. Sensitivity and NPV at 3 hours for both assays were 98% and 99%, respectively. Combining the measurement at admission with the relative change at 3 hours yielded positive predictive values of 96% for both assays.

Comment: These data indicate that, for patients with suspected acute coronary syndrome, results of either troponin I assay 3 hours after emergency department admission can be used to rule out AMI with 99% accuracy, and the relative change in assay results from admission to 3 hours can be used to identify patients with high likelihood of AMI who need immediate invasive diagnostic and therapeutic procedures. This is exciting news.

— John A. Marx, MD, FAAEM

Published in Journal Watch Emergency Medicine January 20, 2012

Citation(s):

Keller T et al. Serial changes in highly sensitive troponin I assay and early diagnosis of myocardial infarction. JAMA 2011 Dec 28; 306:2684.

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Reader Remarks:

Review and add to remarks on this article

• Elevated Troponins
  Bernard A. Yablin, URMC-ret asst clin prof, 23 Jan 2012 11:01 AM EST
  Specialty: Pediatrics
  How long does the troponin elevation last.Can it persist 3 days or more or will it return to normal by... [more]
• Importance
  Norman M. Canter, M.D., 23 Jan 2012 12:49 PM EST
  Specialty: Inactive (Retired)
  This represents a radical step forward in the detection and therefore in the timely treatment of acute myocardial infarction.
• troponin assay
  barry f. schwartz, 23 Jan 2012 12:51 PM EST
  Specialty: Surgery, Urological
  Don't see much differences between the two assays.
• Elevated troponins
  Dr. K. V. Sahasranam Kalpathy, Baby Memorial Hospital Calicut INDIA, 31 Jan 2012 12:42 PM EST
  Specialty: Cardiovascular Disease
  It is mentioned in the article that the hsTI is important in diagnosing ACS 3 hours after "admission". What is... [more]

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