This guideline covers assessing and diagnosing recent chest pain in people aged 18 and over and managing symptoms while a diagnosis is being made. It aims to improve outcomes by providing advice on tests (ECG, high-sensitivity troponin tests, multislice CT angiography, functional testing) that support healthcare professionals to make a speedy and accurate diagnosis. NICE has also produced a guideline on managing acute coronary syndromes. In November 2016, we reviewed the evidence for high-sensitivity troponin tests, non-invasive imaging and exercise ECG for adults with acute chest pain, and diagnostic testing for adults with stable chest pain. We changed and added some recommendations in section 1.2 and section 1.3.