Background: Distinguishing between viral and bacterial pneumonia is paramount for antimicrobial stewardship. The biomarker procalcitonin has shown potential-its serum levels rise with bacterial infection and remain normal in its absence. Yet its application in medical practice remains controversial. Not using antibiotics based on procalcitonin-driven guidelines can be considered as a legal liability. Since the USA features more aggressive medical litigation practices compared with Europe, we hypothesized that there should also be an intercontinental difference for the use of procalcitonin.
Methods: Systematic review of original research on procalcitonin used for pneumonia in the USA and Europe, identified via PubMed and Medline covering 2013-2024. PRISMA flow diagram and risk bias assessment were applied.
Results: Thirty reports met our inclusion and exclusion criteria (17 from Europe, 12 from the USA, and 1 mixed, 24 covered adults, 6 were pediatric). For adults, the vast majority of European and all US-based studies demonstrated an association between higher procalcitonin levels and bacterial pneumonia. Regarding children, all European studies demonstrated correlation while in the USA the results were mixed. The effect of procalcitonin-based guidelines on antibiotic use yielded mixed results among adults in both Europe and the USA, with about half of the studies showing antibiotic stewardship benefit. There were too few pediatric studies covering this research end point to allow for comparison.
Conclusions: Procalcitonin proved a useful tool for differentiating bacteria from viral pneumonia in both Europe and the USA. No consistent intercontinental differences were identified regarding the application of procalcitonin-driven antibiotics stewardship for pneumonia.
Keywords: Antibiotic stewardship; Antibiotics stewardship; Bacterial pneumonia; Biomarker; Pneumonia; Procalcitonin; Viral pneumonia.
Copyright © 2026. Published by Elsevier Inc.