Objective: To assess the diagnostic performance of high-sensitivity troponin T (hs-TnT) in patients with suspected non-ST elevation acute coronary syndrome (NSTE-ACS); confirm whether it shortens the time to diagnosis; and analyze the clinical consequences derived from its use., Method: A prospective, longitudinal observational study was carried out in 5 emergency care departments. Patients seen for chest pain with suspected of NSTE-ACS were consecutively included. Patient care followed the internal protocols of the center, based on the consensus guidelines of the European Society of Cardiology. Serial conventional cardiac troponin (cTn) and hs-TnT determinations were made., Results: A total of 351 patients were included in the study. A final diagnosis of acute myocardial infarction (AMI) was established in 77 patients, with unstable angina in 102, and no acute coronary syndrome in 172 patients. The hs-TnT values were above percentile 99% in a large number of patients without AMI. In the initial determination, the diagnostic sensitivity of the hs-TnT was significantly greater than that of cTn (87.0% vs. 42.9%), which led to a negative predictive value of 95.1%., Conclusions: High-sensitivity troponin T improves diagnostic performance compared with conventional troponin assay, shortens the time to diagnosis, and identifies a larger number of patients with smaller myocardial infarctions., (Copyright © 2018. Publicado por Elsevier España, S.L.U.)