From the Guidelines
Procalcitonin (PCT) should be used to guide antibiotic therapy decisions in adults with suspected sepsis, as it has been shown to reduce antibiotic duration and improve mortality, with levels <0.5 ng/mL or a decrease of >80% from peak values indicating effective therapy and potential discontinuation of antibiotics. PCT levels typically rise significantly in bacterial infections but remain low in viral infections or non-infectious inflammatory conditions. For adults with suspected sepsis, PCT levels >0.5 ng/mL suggest bacterial infection, while levels >2 ng/mL strongly indicate sepsis. Serial PCT measurements are recommended to monitor treatment response, with declining levels suggesting effective therapy. When using PCT to guide antibiotic discontinuation, therapy can generally be stopped when levels fall below 0.5 ng/mL or decrease by >80% from peak values, as shown in a recent meta-analysis of 11 RCTs involving 4,482 patients 1. This approach has been shown to reduce antibiotic duration and improve mortality, without increasing adverse outcomes. However, PCT should always be interpreted alongside clinical assessment and other diagnostic findings, as false positives can occur in conditions like trauma, surgery, and certain malignancies. PCT testing is particularly useful in respiratory infections, where studies show the greatest benefit in reducing unnecessary antibiotic use while maintaining patient safety. A recent systematic review and meta-analysis evaluated the diagnostic accuracy of PCT and CRP in the diagnosis of sepsis in adults, and found that PCT had a higher diagnostic accuracy and specificity than CRP 1. The use of PCT to guide antibiotic therapy decisions is supported by several studies, including a meta-analysis of 16 studies and greater than 5000 patients, which showed that PCT-guided antibiotic discontinuation appeared to decrease antibiotic utilization by 1 day and improve mortality 1. Overall, the use of PCT to guide antibiotic therapy decisions in adults with suspected sepsis is a valuable tool, and can help reduce antibiotic duration and improve mortality, while maintaining patient safety. Some key points to consider when using PCT to guide antibiotic therapy decisions include:
- PCT levels <0.5 ng/mL or a decrease of >80% from peak values indicate effective therapy and potential discontinuation of antibiotics
- Serial PCT measurements are recommended to monitor treatment response
- PCT should always be interpreted alongside clinical assessment and other diagnostic findings
- PCT testing is particularly useful in respiratory infections, where studies show the greatest benefit in reducing unnecessary antibiotic use while maintaining patient safety.
From the Research
Procalcitonin Guidance in Sepsis
- Procalcitonin guidance has been shown to reduce antibiotic duration in adult patients with suspected or confirmed sepsis, with no adverse impact on mortality or length of ICU stay 2.
- Procalcitonin can accurately differentiate culture-negative sepsis from noninfectious systemic inflammatory response syndrome (SIRS), contributing to early diagnosis and effective management of these conditions 3.
Diagnostic Role of Procalcitonin
- High initial procalcitonin levels are a sensitive marker of bacterial infection, and the degree of procalcitonin elevation may determine which patients are at greater risk for adverse outcomes 4.
- Procalcitonin elevation may be used as an indication for initiation of antibiotic treatment, and antibiotics may be discontinued once procalcitonin normalizes, leading to reduced antibiotic consumption 4.
Procalcitonin-Guided Management Algorithms
- Procalcitonin-guided management algorithms may reduce infection-associated adverse events, 28-day mortality, and cost of hospitalization in sepsis patients 5.
- Biomarkers such as procalcitonin can provide decision support for antibiotic use and may identify patients with a low likelihood of infection, guiding duration of antibiotic therapy 6.
Clinical Applications
- Procalcitonin can be a useful diagnostic and prognostic biomarker for patients presenting to the Emergency Department with symptoms suggestive of sepsis 4.
- Procalcitonin guidance may be effective in reducing long-term infection-associated adverse events in sepsis, although further research is required to determine its impact on patient outcomes 5.