Algorithm for procalcitonin-guided antibiotic discontinuation in clinically stable adult patients with known or suspected community-acquired pneumonia*

CAP: community-acquired pneumonia.
* Procalcitonin has not been well studied in immunocompromised patients, trauma or surgery patients, pregnant women, patients with cystic fibrosis, and patients with chronic kidney disease. The algorithm may not be applicable to these populations or other patients with complex comorbidities.
¶ Optimal thresholds have not been precisely determined. Some experts use a lower threshold, typically 0.1 ng/mL when deciding to discontinue antibiotics.
Δ Decisions to stop antibiotics should be made in combination with clinical judgment and presume that the patient is stable and that a bacterial infection that requires a longer course of therapy, such as CAP complicated by bacteremia, was not identified.
◊ Systemic inflammation due to other causes, such as burns, trauma, surgery, pancreatitis, malaria, or invasive candidiasis can also lead to elevated procalcitonin levels.
§ Reaching a procalcitonin level of <0.25 ng/mL is not a requirement for antibiotic discontinuation. For patients with clinically resolved pneumonia and levels >0.25 ng/mL, clinical judgment alone is adequate.