Impact of the implementation of highly sensitive cardiac troponin T assay in a university hospital setting

Troponin is the gold standard for diagnosing myocardial necrosis. Roche Diagnostics has recently replaced the fourth-generation troponin T (TnT) assay with a new highly sensitive method (hsTnT). In our 600-beds university hospital, we replaced TnT (cut-off 0.03 μg/L) with hsTnT (cut-off 15 ng/L). After three months, we audited the impact of hsTnT by comparing data with the same period one year before. After hsTnT implementation, a 5.4% increase of troponin tests was recorded. A positive result was found in 31.7% of TnT and 58.7% of hsTnT (+85%), corresponding to 22.2% and 47.0% positive patients, respectively (P <0.0001). 64% of hsTnT positive results fell in the 16-65 ng/L range, determined as negative with TnT. Considering troponin curves, 39.1% for TnT and 69.0% for hsTnT had at least one result positive (P <0.0001). When the positive curves were classified as typical/atypical according to the reference change value, the difference in percentage of positive curves displaying a typical marker release became not significant (17.2% for TnT vs. 20.5% for hsTnT, P = 0.32). Using hsTnT there was an increase (+85%) in patients with positive troponin who were hospitalized, but also the rate of discharged positive patients increased (from 8.5% to 26.6%). The introduction of hsTnT markedly increased the number of positive tests. However, in interpreting positive results, the evaluation of marker release may keep specificity at the same level of TnT. The triage of hsTnT positive patients in Emergency Department showed that biomarker results are only one of factors considered for clinical decisions.