Procalcitonin Testing: Can It Shorten Sepsis Antibiotic

Why did COVID-19 increase concern about antibiotic resistance?

The CDC's COVID-19 and antimicrobial resistance overview, updated in February 2025, describes a major setback in infection prevention. Almost 80% of patients hospitalized with COVID-19 received antibiotics between March and October 2020. Antibiotics cannot treat SARS-CoV-2 itself, although patients with an additional bacterial infection may need them. These figures describe early pandemic care, rather than prescribing rates today. [CDC overview](https://www.cdc.gov/antimicrobial-resistance/data-research/threats/COVID-19.html)

Antibiotic exposure was only part of the problem. The CDC also identifies staffing shortages, longer admissions and greater use of ventilators and catheters as contributors to hospital infection risks. Across seven pathogens, resistant hospital-onset infections and associated deaths each increased by at least 15% between 2019 and 2020. That history helps explain the interest in treatment strategies that reduce unnecessary antibiotic days while preserving effective care. [CDC findings](https://www.cdc.gov/antimicrobial-resistance/data-research/threats/COVID-19.html)

What did the ADAPT-Sepsis trial find about antibiotic duration?

ADAPT-Sepsis, published online in JAMA in December 2024, compared daily procalcitonin guidance, C-reactive protein guidance and standard care. Over 28 days, average antibiotic duration was 9.8 days with procalcitonin guidance versus 10.7 with standard care. CRP guidance did not significantly reduce this outcome. [ADAPT-Sepsis trial](https://pmc.ncbi.nlm.nih.gov/articles/PMC11862976/)

Safety requires qualification. Mortality at 28 days was 20.9% with procalcitonin guidance and 19.4% with standard care. The comparison met the trial's predefined noninferiority criterion, which allowed a 5.4-percentage-point margin; it did not establish identical risks or improved survival. Only 19 participants had SARS-CoV-2 infection, limiting conclusions specifically about COVID-19. [Trial results and limitations](https://pmc.ncbi.nlm.nih.gov/articles/PMC11862976/)

When can procalcitonin help clinicians stop antibiotics?

The 2026 Surviving Sepsis Campaign guidelines conditionally support combining procalcitonin results with clinical assessment in this setting, while rating the evidence as low certainty. Source control means addressing the origin of infection, such as draining an infected collection. A laboratory result cannot substitute for that intervention or for reassessment of the patient's condition. The same guidelines favor clinical assessment over adding procalcitonin when deciding whether to start antibiotics for possible or probable sepsis. [Surviving Sepsis Campaign recommendations](https://www.sccm.org/clinical-resources/guidelines/guidelines/surviving-sepsis-campaign-international-guidelines-for-management-of-sepsis-and-septic-shock-2026)

COVID-19 requires particular caution. NICE states that evidence is insufficient to recommend routine procalcitonin testing to guide antibiotic decisions in people with COVID-19, and that the most appropriate threshold remains uncertain. Its guidance instead considers the wider diagnostic picture, including imaging and respiratory or blood samples. The practical implication is that a biomarker can contribute to a treatment decision, but should not become an automatic instruction to continue or stop a medicine. [NICE guidance on co-infections](https://www.nice.org.uk/guidance/NG191/chapter/identifying-and-managing-co-infections)