Creatine kinase-MB (CK-MB) is a widely tested enzyme in cardiac disease and thus has important clinical implications.

We relate the scenario of a young patient presenting with chest pain whose CK-MB levels remained inordinately elevated despite a normal total CK level, resolution of symptoms and exclusion of coronary artery disease.

Further analysis by electrophoresis revealed the presence of a rare molecular variant of creatine kinase: macro-CK type 1. While this may be a benign finding, there are sparse data demonstrating an association with non-cardiac pathologies such as malignancy, endocrinopathies, connective tissue and autoimmune diseases.

Thus, after further exclusion of these associated conditions, the patient was reassured on the likely benign nature of macro-CK in this case.