Procalcitonin-based algorithms to initiate or stop antibiotic therapy in critically ill patients: Is it time to rethink our strategy?

• Previous reviews and meta-analyses of procalcitonin (PCT) combine use in different antibiotic settings.
• The current review separated these antibiotic settings and included additional recent studies.
• Recommendations for PCT use in each antibiotic setting are provided.

Procalcitonin (PCT)-based antibiotic management algorithms for critically ill patients have been described in the literature. An evaluation of the available evidence demonstrates that studies have utilised PCT in various clinical scenarios: for the initiation of antimicrobials; for cessation or de-escalation of antimicrobials; or for the combination of both strategies. Current PCT reviews and meta-analyses have combined studies from all different clinical scenarios. However, there may be significant variations in algorithm compliance and clinical outcomes associated with the use of PCT in these different strategies. As such, the current review focused on separating out the studies utilising PCT in the critically ill population for different treatment strategies. Based on this review, we would recommend that PCT should not be used as the sole deciding factor for the initiation of antimicrobials. As such, PCT should not be obtained in patients who do not exhibit evidence of infection. In patients who do have signs of infection and antimicrobials have been initiated, a strategy that utilises PCT for the discontinuation or de-escalation of antimicrobials is likely to decrease the duration of treatment without adversely affecting outcome.