AAFP: “A procalcitonin-guided antibiotic therapy algorithm should be used to decrease antibiotic use in adults with acute respiratory infections. (Strength of Recommendation [SOR]: A, based on a meta-analysis of multiple randomized controlled trials [RCTs].)” Read the article here.
“Procalcitonin is a biomarker that is elevated with bacterial infections but not with viral infections. The laboratory test for procalcitonin has a high sensitivity and can help exclude bacterial pneumonia in patients with acute heart failure, which can help expedite appropriate therapy with antibiotics. If the procalcitonin level is low a bacterial infection is less likely and antibiotics should not be given.
Wettersten N, Maisel AS: Biomarkers for heart failure: An update for practitioners of internal medicine. Am J Med 2016;129(6):560-567. “ABMF critique 2017
This Uptodate.com article supports the use of procalcitonin in CAP (and I think Sepsis).
PROCALCITONIN can be used to discontinue antibiotics within 48 hrs in critically ill patients if the level has decreased by 80% or more from its peak value or to 0.5 ug/L or lower, not just pneumonia or sepsis. Not only did this study showed a reduction in daily defined dose of antibiotics, it also showed a significant decrease in mortality.
http://www.mayomedicallaboratories.com/test-catalog/Clinical+and+Interpretive/83169