Elevated cardiac troponin I (cTnI) levels in patients hospitalized with chest pain often lead to a diagnosis of acute myocardial infarction (MI) or unstable angina. However, as we describe in this review, this finding may occur in other conditions, leading to an incorrect diagnosis and other, sometimes invasive, tests. We review briefly cTnI, its release and detection. We describe the various conditions that may cause an elevated cTnI level and give possible explanations for these findings, and we offer some guidelines for diagnosis in patients with an elevated cTnI.