Does Measuring Serum Concentration of Procalcitonin in Critically Ill Patients Assist in Stopping Antibiotic Therapy?

Most successful debates start with a good understanding of the question at hand. We would like to begin the “pro” side of this debate by examining the question in detail. Like most diagnostic tests, the procalcitonin (PCT) test itself serves little purpose if not acted upon. In other words, for PCT monitoring to be helpful, it must possess characteristics that make it actionable. In addition, for the purpose of this debate, we will consider critically ill patients to be those who are treated in the intensive care unit and will ignore use of PCT measurement in the emergency department or other inpatient or outpatient settings. Lastly, reference to “stopping antibiotic therapy” signifies that an antibiotic has already been started. Simply put, the initial decision to start antibiotics has passed (independent of any quantification of PCT), and the decision now is whether the antibiotics can be de-escalated or discontinued. Such a change might occur because new clinical information and/or the PCT result has rendered obsolete the original decision to start antibiotics, or because the original infection has been adequately treated. In the remainder of this article, we will discuss in more detail the use of PCT measurement within the context of this question and provide recommendations on its most appropriate use.