Coronary artery spasm (CAS) is the most prevalent endotype in patients with angina with non-obstructive coronary arteries. It also plays an important role in patients with acute and chronic coronary syndrome. Incomplete intracoronary provocation testing to exclude CAS as the etiology of chronic or acute coronary syndrome leads to an incorrect diagnosis and, subsequently, inappropriate treatment. Identification of the correct endotypes of chronic and acute coronary syndromes is critical for the selection of appropriate therapy, which then affects disease outcome. It is therefore essential to complete intracoronary provocation testing for right and left coronary arteries in order to reach a correct diagnosis with regard to CAS, including epicardial vasospasm and microvascular spasm. If CAS is found not to be the cause of myocardial ischemia, then a microvascular functional assessment is the next step to identify the etiology of the ischemic event. A comprehensive assessment of CAS is essential before appropriate treatments can be started.