Will future troponin measurement overrule the ECG as the primary diagnostic tool in patients with acute coronary syndrome?

To improve patient outcome, point-of-care (POC) cardiac troponin I/T (cTn I/T) tests applied in a prehospital setting and/or emergency department might play a role as a substitute for central hospital laboratory high-sensitivity (hs) cTn I/T testing if their analytical and clinical performance are equivalent to central hospital laboratory hs cTn I/T tests and if they fulfill an unmet clinical need in the diagnostic work-up of patients with acute coronary syndrome (ACS). To date, current point-of-care (POC) cTn I/T tests are not yet sufficiently analytically sensitive and do not provide accurate and precise values in the reference range nor at the 99th percentile of a healthy reference population. Awaiting the development of improved hs POC cTn I/T tests, current POC cTn I/T tests should be combined with ECG as it takes several hours to detect a rise of cTn I/T in the circulation whereas ischemia-induced ECG changes may be observed soon after onset of chest pain. Although patients with acute ST-segment elevation myocardial infarction (STEMI) are generally diagnosed by ischemic symptoms and ECG only, hospitalized patients with non-STEMI and unstable angina pectoris (UAP) should preferentially be tested with ECG and central hospital laboratory hs cTn I/T tests unless the ECG has already demonstrated diagnostic changes. More evidence and future trials are needed to find out whether in patients with NSTE ACS hs cTn I/T tests should be combined with other tests, such as a test of B-type natriuretic peptide or NT-proBNP.