Applying clinical decision aids for the assessment and management of febrile infants presenting to emergency care in the UK and Ireland: Febrile Infant Diagnostic Assessment and Outcome (FIDO) Study protocol.

introductionFebrile infants 90 days and younger are at risk of invasive bacterial infections (bacteraemia and meningitis) and urinary tract infections. Together this is previously termed serious bacterial infection with an incidence of approximately 10-20%. The National Institute for Health and Care Excellence guidance advocates a cautious approach with most infants requiring septic screening, parenteral broad-spectrum antibiotics and hospital admission. Internationally, variations exist in the approach to febrile infants, with European and North American guidance advocating a tailored approach based on clinical features and biomarker testing. None of the available international clinical decision aids (CDAs) has been validated in the UK and Irish cohorts. The aim of the Febrile Infant Diagnostic Assessment and Outcome (FIDO) Study is to prospectively validate a range of CDAs in a UK and Irish population including CDAs that use procalcitonin testing. METHODS AND ANALYSIS: The FIDO Study is a prospective multicentre mixed-methods cohort study conducted in UK and Irish hospitals. All infants aged 90 days and younger presenting with fever or history of fever (≥38°C) are eligible for inclusion. Infants will receive standard emergency clinical care without delay. Clinical data and blood samples will be collected, and consent will be obtained at the earliest appropriate opportunity using research without prior consent methodology. The performance and cost-effectiveness of CDAs will be assessed. An embedded qualitative study will explore clinician and caregiver views on different approaches to care and perceptions of risk. ETHICS AND DISSEMINATION: This study was reviewed and approved by the Office for Research Ethics Committees Northern Ireland-Health and Social Care Research Ethics Committee B, Public Benefit and Privacy Panel for Health and Social Care Scotland, and Children's Health Ireland Research and Ethics Committee Ireland. The results of this study will be presented at academic conferences and in peer-reviewed publications. TRIAL REGISTRATION NUMBER: NCT05259683.