Pickering JW, et al. - Researchers conducted this study to assess the clinical accuracy for acute myocardial infarction (AMI) of a single troponin concentration measured on arrival to the emergency department (ED) with a new-generation, higher precision point-of-care assay with a 15-minute turnaround time. Findings revealed comparable discrimination ability of a novel point-of-care troponin assay that can produce a result 15 minutes after blood sampling to an hs-cTnI assay for ruling out AMI after a single blood test. Earlier decision-making may be facilitated and safe discharge of a large proportion of low-risk patients can be expedited with use in the ED.

Methods

• Authors conducted this observational study at a single urban regional ED.
• They included the adults presenting acutely from the community to the ED with symptoms suggestive of AMI.
• They measured the troponin concentrations on ED arrival with both a novel point-of-care assay (i-STAT TnI-Nx; Abbott Point of Care) and a high-sensitivity troponin I assay (Architect hs-cTnI; Abbott Diagnostics).
• Type 1 AMI during index presentation was included in the primary outcome.
• They compared the discrimination ability of the TnI-Nx assay with the hs-cTnI assay using the area under receiver operator characteristic curve (AUC) and sensitivity, negative predictive value, and the proportion of negative test results at thresholds with 100% sensitivity.

Results

• Of 354 patients (255 [72.0%] men; mean [SD] age, 62 [12] years), 57 (16.1%) experienced an AMI.
• In < 3 hours after symptom onset, 85 patients (24.0%) presented to the ED.
• Findings did not suggest any difference between the AUC of the TnI-Nx assay (0.975 [95% CI, 0.958-0.993]) and the hs-cTnI assay (0.970 [95% CI, 0.949 to 0.990]; P=0.46).
• A total of 201 (56.7%) patients were identified by a TnI-Nx assay result of < 11 ng/L as low risk, with a sensitivity of 100% (95% CI, 93.7% to 100%) and a negative predictive value of 100% (95% CI, 98.2% to 100%).
• In comparison, 154 patients were identified (43.5%) as low risk by an hs-cTnI assay result of < 3 ng/L, with a sensitivity of 100% (95% CI, 93.7% to 100%) and a negative predictive value of 100% (95% CI, 97.6% to 100%).