Abstract
We read with interest the recent article of Aldous et al., 1 who concluded that the novel Roche Elecsys highly sensitive (HS) troponin T (TnT) (Roche Diagnostics GmbH, Mannheim, Germany) immunoassay was superior to the former traditional TnT method and almost equivalent to the Abbott Architect (Abbott Diagnostics, Abbott Park, IL, USA) troponin I (TnI) third generation TnI 3 for the diagnosis of acute myocardial infarction (AMI) in the emergency department. In order to establish whether a novel HS TnI immunoassay is characterized by similar diagnostic performance, Beckman Coulter prototype HS-AccuTnI (Beckman Coulter Inc, Brea, CA, USA), Beckman Coulter AccuTnI, as well as Roche HS-TnT (Roche Diagnostics GmbH), were measured on 57 consecutive patients presenting at the emergency department of the Academic Hospital of Parma with suspected AMI, within three hours from symptom onset. AccuTnI and the novel HS-AccuTnI were assessed on Access 2 (Beckman Coulter Inc), whereas HS-TnT was measured on Cobas® (Roche Diagnostics GmbH). The diagnostic performance of the three immunoassays was assessed by receiver operating characteristic (ROC) curve analysis. Nine out of the 57 patients (i.e. 16%) had a final diagnosis of AMI. The diagnostic performance of the three immunoassays, as reflected by the respective areas under the curve (AUCs) in ROC analysis, was 0.90 (95% CI, 0.79–1.00; P< 0.001) for Beckman Coulter AccuTnI, 0.89 (95% CI, 0.78–0.99; P< 0.001) for Roche Hs-TnT and 0.88 (95% CI, 0.75–1.00; P< 0.001) for Beckman Coulter HS-AccuTnI, respectively. The AUCs were not significantly different (P= 0.576). At the manufacturer cut-off, i.e. 99th percentile of the reference range, sensitivity and specificity were 78% and 73% for Beckman Coulter AccuTnI (30 ng/L), 100% and 62% for Roche Hs-TnT (14 ng/L), and 100% and 51% for Beckman Coulter HS-AccuTnI (8.6 ng/L), respectively. Optimal performance (i.e. 100% sensitivity) was observed at the following cut-offs: 17 ng/L (65% specificity) for Roche HS-TnT, 12.6 ng/L (64% specificity) for Beckman Coulter HS-AccuTnI and 10 ng/L (67% specificity) for Beckman Coulter AccuTnI. Although our study is relatively small, it suggests that the diagnostic performance of the novel prototype HS-AccuTnI and HS-TnT is broadly comparable with that of AccuTnI in patients presenting at the emergency department with suspected AMI.
DECLARATIONS