Early diagnosis and triage of acute coronary syndrome (ACS) is important for immediate initiation of appropriate evidence-based therapy.

Triage of these patients; however, remains a challenge, as many of them may appear well at presentation.

This triage is often based on clinical presentation, 12-lead ECG and cardiac biomarkers, scoring system, and non-invasive imaging.

Cardiovascular biomarkers can be useful for the diagnostic and prognostic assessment of patients with chest pain.

There are important differences in the performance of highly sensitive and conventional cardiac troponin (cTn) assays. A cTn concentration >99th percentile upper reference limit, which is assay-dependent, is an indicator of myocardial injury. The coefficient of variation at the 99th percentile upper reference limit for each assay should be 10%.

Newer fifth-generation high sensitivity (hs)-cTn T and I assays can detect troponin at concentrations 10- to 100-fold lower than conventional assays.

The 2020 ESC guidelines recommend to use the 0h/1h or 0h/2h algorithm which are well validated in large multicentric studies.

The positive predictive value (PPV) of MI in patients getting in the ‘rule-in’ criteria is 75% and negative predictive value (NPV) for patients in the ‘rule-out’ criteria is 99.

To conclude:

• Accurate diagnosis of ACS has life-saving implications and requires a careful assessment.
• High-sensitivity troponin (hs-Tn) assay measurements are recommended over less sensitive ones.
• It is recommended to use the 0 h/1 h algorithm (best option) or the 0 h/2 h algorithm (second-best option). Use with clinical assessment of pretest likelihood of CAD, chest pain history, and a 12-lead ECG.
• Use clinical scores and non-invasive imaging, such as echocardiography and coronary computed tomography angiography (CCTA).