What is procalcitonin (PCT)?

From the Guidelines

Procalcitonin levels can be used to support shortening the duration of antimicrobial therapy in sepsis patients and to guide the discontinuation of empiric antibiotics in patients who initially appeared to have sepsis, but subsequently have limited clinical evidence of infection. The use of procalcitonin levels in clinical practice is supported by several studies, including a meta-analysis that showed no significant difference in 28-day mortality or hospital mortality and a median reduction of approximately 2 days in the length of antibiotic therapy with procalcitonin guidance 1. Additionally, a retrospective study found that using procalcitonin levels to guide antibiotic therapy resulted in a more than two-fold reduction in defined daily doses of antibiotic use without any increase in mortality among patients with COVID-19 1. Some key points to consider when using procalcitonin levels in clinical practice include:

• Procalcitonin levels can be elevated in patients with COVID-19 due to generalized inflammatory activation rather than bacterial co-infection 1
• A low procalcitonin value early in the course of confirmed COVID-19 illness can guide the withholding or early stopping of antibiotics, especially among patients with less severe disease 1
• The ferritin-to-procalcitonin ratio has been reported to have a sensitivity of 85% and specificity of 56% for differentiating COVID-19 from bacterial pneumonia at a cutoff level of ≥877 1
• Antimicrobial stewardship programs can assist with appropriate utilization of antibiotics in patients with COVID-19 using strategies such as guideline development, procalcitonin-guided therapy, and antimicrobial restriction 1. It is essential to note that procalcitonin levels should be used in conjunction with clinical judgment and other diagnostic tools to guide antibiotic therapy, as no single marker can perfectly distinguish viral from bacterial pneumonia 1.

From the Research

Procalcitonin as a Diagnostic Marker

• Procalcitonin (PCT) is a biomarker that has been shown to be useful in the diagnosis and management of sepsis 2, 3, 4, 5, 6
• PCT has been found to have high diagnostic accuracy for sepsis, especially in comparison to other biomarkers 2, 3
• The use of PCT can help reduce unnecessary antimicrobial therapy and improve patient outcomes 2, 5, 6

Clinical Utility of Procalcitonin

• PCT can be used to guide antibiotic therapy in patients with suspected sepsis or bacterial infection 5, 6
• High initial PCT levels are a sensitive marker of bacterial infection, and the degree of PCT elevation may determine which patients are at greater risk for adverse outcomes 5
• PCT-guided management algorithms can lead to reduced antibiotic consumption, but further research is needed to determine whether this approach ensures better outcomes for patients 5, 6

Cost-Effectiveness of Procalcitonin Testing

• The use of PCT testing has been found to be cost-effective in guiding antibiotic therapy for patients with suspected sepsis or bacterial infection 6
• PCT testing can lead to cost-savings and a small quality-adjusted life-year (QALY) gain, especially in intensive care unit (ICU) settings and emergency department (ED) settings 6
• However, further research is needed to assess the effectiveness and cost-effectiveness of PCT testing in different settings and populations 6

Limitations and Challenges

• PCT is not a universal and perfect biomarker, as it can also be increased in noninfectious disease conditions 2, 4
• The interpretation of PCT results must be done carefully in the context of medical history, physical examination, and microbiological assessment 3, 5
• Further research is needed to address the limitations and challenges of using PCT as a diagnostic marker for sepsis 2, 4, 6