Despite over 3,000 peer-reviewed articles on procalcitonin (PCT) since 2004, guidance on its usage is sparse.1 An analysis of more than 500 United States hospitals in the Premier Healthcare Database found large differences in utilization exist across regions (115 PCT encounters per 10,000 patients in the Northeast vs. 408 to 576 in other regions) and teaching vs. non-teaching hospitals (345 vs. 530 PCT encounters per 10,000 patients, respectively).2 The purpose of this work is to describe a case that exemplifies the caveats in PCT interpretation and to summarize the current knowledge of the clinical utilization of PCT.