What is procalcitonin (PCT)?

From the Guidelines

Procalcitonin should be used to guide antibiotic therapy decisions in critically ill patients, particularly in respiratory infections and sepsis, as it can help reduce unnecessary antibiotic use and improve patient outcomes. Procalcitonin is a biomarker that rises significantly during bacterial infections, but remains relatively low during viral infections or non-infectious inflammatory conditions, with normal levels typically below 0.05 ng/mL 1. Values above 0.5 ng/mL suggest possible bacterial infection, and levels exceeding 2.0 ng/mL strongly indicate severe bacterial infection or sepsis.

Key Points to Consider

• Procalcitonin testing is most valuable in determining whether antibiotics are necessary and when they can be safely discontinued, as supported by a recent systematic review and meta-analysis that found PCT-guided antibiotic treatment in ICU patients with infection and sepsis patients resulted in improved survival and lower antibiotic treatment duration 1.
• The test should not be used in isolation but interpreted alongside clinical assessment, other laboratory findings, and imaging studies, as certain conditions like trauma, surgery, and some cancers can cause elevated procalcitonin levels without bacterial infection 1.
• A meta-analysis of 11 RCTs involving 4,482 patients reported that PCT-guided antibiotic treatment in ICU patients with infection and sepsis patients resulted in improved survival and lower antibiotic treatment duration, highlighting the potential benefits of procalcitonin-guided therapy 1.
• The largest systematic review and meta-analysis to date of 16 studies and greater than 5000 patients showed that PCT-guided antibiotic discontinuation appeared to decrease antibiotic utilization by 1 day and improve mortality, although the evidence was of low certainty due to the substantial risk of bias, indirectness of effect, and unknown application of antibiotic stewardship programs in control arms 1.

Clinical Application

• Procalcitonin levels can be used to support the discontinuation of empiric antibiotics in patients who initially appeared to have sepsis, but subsequently have limited clinical evidence of infection, as suggested by the Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock: 2016 1.
• In patients with sepsis, procalcitonin levels can be used to support shortening the duration of antimicrobial therapy, as recommended by the Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock: 2016 1.
• However, the use of procalcitonin to determine the need for initial antibiotic therapy in community-acquired pneumonia is not recommended, as it may underestimate the burden of bacterial superinfections, which are associated with high mortality 1.

From the Research

Procalcitonin Overview

• Procalcitonin (PCT) is a biomarker used to improve the diagnosis of bacterial infections and guide antibiotic therapy 2, 3, 4, 5.
• PCT levels are elevated in bacterial infections, but not in viral infections or other inflammatory conditions 4.

Clinical Applications

• PCT-guided therapy has been shown to reduce antibiotic use in various clinical settings, including upper and lower respiratory tract infections, post-operative infections, and severe sepsis 2, 3, 4.
• A cutoff value of 0.25 μg/L in non-ICU patients or 0.5 μg/L in ICU patients can be used to guide initiation and discontinuation of antibiotic therapy 4.
• PCT levels can help guide the need for empirical antibiotic therapy, source control for infections, and duration of antibiotic therapy 5.

Efficacy and Safety

• Procalcitonin guidance has been shown to reduce antibiotic duration without adverse effects on patient outcomes, including mortality and length of ICU stay 6.
• A systematic review and meta-analysis of 10 randomized controlled trials found that procalcitonin-guided patients had shorter antibiotic durations compared to controls 6.

Studies and Findings

• Numerous studies have demonstrated the effectiveness of PCT-guided therapy in reducing antibiotic use and improving patient outcomes 2, 3, 4, 5, 6.
• The use of PCT has been supported by various studies, including randomized controlled trials and observational studies, in different clinical settings and patient populations 2, 3, 4, 5, 6.