How does AMS link to PCT?

The concept of procalcitonin-guided antimicrobial stewardship was first tested in Emergency Department (ED) patients with infection of the lower respiratory tract.

As PCT remains low (undetected) in viral infection and increases in bacterial infection, original studies recommended very strongly or strongly against the use of antibiotics if PCT levels were <0.1 μg/L or <0.25 μg/L, respectively. But, the studies allowed for for clinicians to use their clinical judgment at the same time. The study by Christ-Crain et al demonstrated significant reduction in antibiotic prescription rates, particularly in patients with bronchitis and COPD exacerbation.

Later studies investigated PCT for the initiation of empirical antibiotic therapy, also using PCT to monitor the response to therapy and to decide on discontinuation on an individual basis. Subsequent studies have demonstrated that the greatest utility of PCT is in guiding antibiotic de-escalation, based on low or downward trending PCT levels without causing patients harm or mortality. Real-life studies have confirmed these findings.

A recent meta-analysis included individual data from over 6700 patients with different types and severities of respiratory infections from 26 randomised-controlled trials. The analysis reviewed the effects of PCT-guided antibiotic decision making, in the context of respiratory infections. The study showed that PCT use in the respiratory infection setting reduces antibiotic exposure (initiation of antibiotics from 86% to 72% and a reduction in overall exposure from 8.1 days to 5.7 days), side effects from antibiotics (decreased from 22.1% to 16.3%) and significantly reduced mortality by 14% (from 10% to 8.6%). Results were consistent for the different clinical settings (i.e. primary care, ED or critical care) and types of infections (pneumonia, bronchitis, COPD exacerbation.

Other studies have demonstrated better survival in the PCT group in intensive care despite lower antibiotic use. PCT has the potential to reduce length of therapy and improve cost in healthcare settings. Most importantly, when it is used judiciously within a clinical context it can lead to reduction of antimicrobial utilisation – which is correlated to a reduced selective pressure on antibiotics (i.e. better for public health), and local microbiota which ultimately improves patient care by reducing exposure to antibiotics.

Further data from settings like haematology, paediatrics, transplant and other immunocompromised patients are required to support specialists and antimicrobial stewards promoting a wise use of this biomarker.

References are available in the see also section below, if you wish to read more about this topic.