Rule-out of non-ST elevation myocardial infarction by five point of care cardiac troponin assays according to the 0 h/3 h algorithm of the European Society of Cardiology

Background: Point of care (POC) assays for cardiac troponins I or T (cTnI or cTnT) may accelerate the diagnosis of patients with suspected acute coronary syndrome (ACS). However, their clinical utility according to the 0 h/3 h algorithm recommended by the European Society of Cardiology (ESC) for non-ST elevation myocardial infarction (NSTEMI) is unknown. Methods: Blood samples from 90 patients with suspected ACS were obtained at hospital admission and 3 h later. Concentrations of cTn were determined using five POC assays (AQT90 FLEX cTnI and cTnT; PATHFAST™ cTnI; Stratus CS 200 cTnI; and Triage MeterPro cTnI) and two guideline-acceptable high-sensitivity (hs) immunoassays. Results: For the diagnosis of NSTEMI (n=15), AUCs for Abbott hs-cTnI and Roche hs-cTnT were 0.86 [95% confidence interval (CI), 0.75–0.96] and 0.88 (95% CI, 0.80–0.95), respectively, at admission, and 0.96 and 0.94, respectively, 3 h later. With the 99th percentile cutoff, their sensitivities were 62% and 92%, respectively, at admission, and 77% and 100%, respectively, 3 h later. The PATHFAST™ cTnI assay showed AUCs of 0.90 (95% CI, 0.82–0.97) and 0.94 (95% CI, 0.89–1.00), respectively, and sensitivities of 67% and 75% at admission and 3 h later, respectively. The other cTn POC assays had AUCs of 0.71 (95% CI, 0.53–0.89) to 0.84 (95% CI, 0.71–0.96) and 0.86 (95% CI, 0.72–0.99) to 0.87 (95% CI, 0.75–0.99) and sensitivities of 39%–50% and 62%–77% at admission and 3 h later, respectively. Conclusions: PATHFAST™ cTnI assay proved itself as comparable to ESC-guideline acceptable hs-cTn assays. The lower sensitivity of the other POC assays limits their clinical utility and would require longer follow-up monitoring of patients for the safe NSTEMI rule-out.