Angina with nonobstructive coronary artery disease (ANOCA) can be found in up to 50 % of patients with chest pain and 25 % of patients with inducible ischemia undergoing coronary angiography [ ]. Unfortunately, many of those patients are diagnosed with non-cardiac chest pain without completing an evaluation for cardiac causes other than obstructive epicardial coronary artery disease. ANOCA is a working diagnosis, not a final diagnosis. ANOCA patients should undergo coronary function testing to identify underlying causes for their complaints, and in many cases, an underlying cardiac cause can be found. Because ANOCA has a high prevalence and comprises a wide range of symptoms that are often under- or misdiagnosed and under- or mistreated, it results in a large burden for the medical system and society. ANOCA patients without proper additional examination or misdiagnosed with noncardiac chest pain often feel misunderstood and insecure, resulting in multiple hospital presentations and unnecessary tests. In addition, current evidence indicates that ANOCA is not a benign condition. These patients are at higher risk for MACE including death, non-fatal myocardial infarction, heart failure, re-hospitalization, and repeated coronary angiography for recurrent angina vs. reference subjects. Even patients with obstructive coronary artery disease can have undiagnosed coronary function abnormalities. In those cases, treatment of the obstructive coronary artery lesions does not take away the anginal complaints.