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Lay summary

Procalcitonin and C-reactive protein are biomarkers, which are naturally occurring substances within the human body. Levels increase in response to bacterial infection, and reduce with effective antibiotic treatment. High quantities in the bloodstream are associated with a diagnosis of sepsis. Testing the levels of these biomarkers can help to guide the length of antibiotic treatment needed. A randomised clinical trial (ADAPT Sepsis) is finding out whether using biomarkers to guide antibiotic duration is effective and safe for patients when compared with standard hospital care.

Our study, PREADAPT-Sepsis, uses a type of research method called a process evaluation. It is being carried out at the same time as the clinical trial, and focuses on the hospital staff. When the clinical team receive biomarker test results they make a decision about whether to start, continue or stop prescribing antibiotics. They have to use their professional judgement to make this decision, which can be influenced by many different factors. We are using questionnaires and interviews to find out how they make their decisions, and to learn why they might or might not use the biomarker test results.
At the end of the study, the results of the clinical trial and process evaluation will be reported together. The overall results will also help us to understand which type of test is most effective, and how we could encourage NHS hospital teams to use it.

Study details

  • Full title of clinical trial: Process evaluation of the ADAPT-Sepsis trial using mixed methods to investigate factors influencing implementation of biomarker-guided antibiotic prescribing in suspected sepsis.
  • Study design: Mixed methods process evaluation (implementation) study
  • Chief Investigator: Ruth Louise Poole
  • Sponsor: Cardiff and Vale University Health Board
  • Sponsor ref: 18/JUL/7475
  • Funding: Intensive Care Society / National Institute for Health and Care Excellence (NICE)
  • ID: ResearchRegistry4244


We presented our work at meetings and conferences, including associated research into the long-term impact of sepsis on survivors:

Poole R.L. (2019) Diagnostic testing for sepsis: procalcitonin. “What do people, NICE and industry want from medical devices?”, Royal Society of Medicine, London, UK, December 2019 [oral presentation].

Poole R.L., O’Connell, Laight T, Carolan-Rees G (2019) Exploring the long-term impact of post-sepsis syndrome. Health Services Research UK, Manchester, UK, July 2019 [rapid-fire oral and poster presentation; abstract 172].

Poole R.L., Blackwood B., Dark P.M. (2017)  PREADAPT-Sepsis PRocess Evaluation of the ADAPT-Sepsis trial: new study proposal. UK Critical Care Research Forum, Birmingham, UK, June 2017 [oral presentation].