The 0/2 h rule-out and rule-in algorithm recommended by the ESC 2020 Guidelines to define the management recommendations for patients with suspected acute coronary syndrome based on fixed thresholds for the assessed four high-sensitivity cardiac troponin assays. ACS, acute coronary syndrome; CCTA, coronary computed tomography angiography; CCU, coronary care unit; ICA, invasive coronary angiography; hs-cTn, high-sensitivity cardiac troponin; NSTEMI, non-ST-segment elevation myocardial infarction.