Diagnostic Validation of a High-Sensitivity Cardiac Troponin I Assay.

Abstract

BACKGROUND\nEmergency departments worldwide are increasingly adopting rapid diagnosis of patients with suspected myocardial infarction (MI) based on high-sensitivity troponin. We set out to assess the diagnostic accuracy of a high-sensitivity cardiac troponin I (hs-cTnI) assay in a prospective study.\n\n\nMETHODS\nIn a cohort study including 1800 patients presenting with suspected acute MI, we developed and temporally validated a 0/1\u2009h diagnostic algorithm using the Siemens Atellica IM hs-cTnI assay. The algorithm was established in the first 928 patients and validated in the following 872 patients.\n\n\nRESULTS\nThe derived algorithm consisted of a baseline rule-out of non-ST-segment elevation MI using a cutoff <3\u2009ng/L in patients with symptom onset ≥3\u2009h or an admission troponin I level <6\u2009ng/L with a Δ change of <3\u2009ng/L from 0\u2009h to 1\u2009h. For rule-in, an admission troponin I level ≥120\u2009ng/L or an increase within the first hour ≥12\u2009ng/L was required. Application of the algorithm to the validation cohort showed a negative predictive value of 99.8% (95% CI, 98.7%-100.0%), sensitivity of 99.1% (95% CI, 95.1%-100.0%), and 48.3% of patients ruled out, whereas 15.1% were ruled in with a positive predictive value of 68.0% (95% CI, 59.1%-75.9%) and specificity of 94.4% (95% CI, 92.5%-96.0%). The diagnostic performance was comparable to guideline-recommended application of an established hs-cTnI assay in a rapid 0/1\u2009h strategy.\n\n\nCONCLUSIONS\nThe Siemens hs-cTnI assay is well suited for application in rapid diagnostic stratification of patients with suspected MI.\n\n\nSTUDY REGISTRATION\nwww.clinicaltrials.gov (NCT02355457).