Superior early diagnostic performance of a sensitive cardiac troponin assay as compared to a standard troponin test in the diagnosis of acute myocardial infarction.

BACKGROUND: New generation cardiac troponin assays have sufficient precision to detect and quantify plasma troponin concentrations below the lower threshold of detection of the currently employed troponin tests. However, diagnostic performance of the newer generation assays in daily clinical practice is not well established.

AIM: To evaluate the diagnostic performance of a sensitive assay as compared to a standard assay in a single reading at admission in the diagnosis of acute myocardial infarction (AMI) in patients presenting to the Emergency Department with chest pain.

METHODS: The study comprised 187 consecutive patients admitted to the Institute of Cardiology in Warsaw in June and July 2010 with chest pain in whom the attending physician ordered troponin assay to rule AMI in or out. In all of these patients, in addition to the standard Dimension Flex Troponin I (Siemens Healthcare Diagnostics, Inc.) the sensitive Architect Stat Troponin I (Abbott Diagnostics) test was assayed. The triage of patients as well as all diagnostic and treatment decisions were left to the discretion of the attending physician who was blinded to the sensitive troponin test readings. The final diagnosis was adjudicated by a team of two cardiologists on the basis of all the available medical records except for sensitive troponin test results.

RESULTS: Mean age of the study cohort (n = 187) was 64.3 ± 13.9 years and 119 (63.6%) were males. The final diagnosis of AMI was adjudicated in 84 (44.9%) patients (mean age 67.5 ± 12.9 years; 119 [63.6%] males). Receiver operating characteristic (ROC) analysis showed greater area under the curve (AUC) for the sensitive cardiac troponin assay compared to the standard assay (AUC = 0.916, 95% CI = 0.866-0.951 vs AUC = 0.863, 95% CI = 0.806-0.909, respectively; p = 0.02) in a single reading at admission. Sensitive assay was characterised by higher sensitivity (87%), specificity (88%), positive (86%) and negative (89%) predictive values in the detection of AMI compared to the standard troponin test (82%, 81%, 78%, and 85% respectively).

CONCLUSIONS: The newer generation sensitive cardiac troponin assay presented superior diagnostic accuracy in the diagnosis of AMI compared to the standard troponin test in a single reading at admission with improved sensitivity and specificity. The sensitive troponin assay has the potential to improve early detection and/or exclusion of AMI.