Determining the feasibility of randomising infants, children and young people to invasive and non-invasive urine sampling techniques (FROG): Protocol for a multicentre randomised controlled feasibility trial and mixed methods perspectives' study of RCT feasibility.

BACKGROUND: Urinary tract infections (UTI) are the second most common serious bacterial infection in children. When healthcare practitioners are unsure if an infant, child, or young person has a UTI they perform a urine test. A midstream sample is recommended by the National Institute for Health and Care Excellence (NICE) for obtaining urine for testing. However, collecting urine from children who are unable to provide a midstream urine sample is challenging. Samples can be collected either by non-invasive (clean catch) or invasive methods (trans-urethral bladder catheter or suprapubic aspirate). Non-invasive methods are slow and prone to contamination but are painless. Invasive methods are less prone to contamination and are quick but can cause pain and distress.

METHODS: This is a mixed methods feasibility study comprising of three parts. Part 1 is a pragmatic multicentre randomised controlled feasibility trial. The trial aims to evaluate the feasibility of conducting an RCT comparing invasive and non-invasive sampling methods for infants, children and young people (N = 100). Resource use will be assessed by parent reported questionnaire and mixed methods descriptors reported by healthcare professionals (n = 24). A cost analysis will assess the urine collection methods, informing a future cost-effectiveness analysis. Part 2 is an embedded mixed methods perspectives' study including interviews with parents (n = 15-20) and children (n = 10-15), five focus groups (n = 6-8 per group) and interviews (n = 10) with healthcare professionals aiming to assess feasibility and acceptability of the trial. Part 3 is a stakeholder (n = 40) consensus meeting determining a final definitive study design.

DISCUSSION: The results of the study will inform a recommendation and decision on progression and design of a definitive RCT for infants, children and young people who have a suspected urine infection but cannot provide a midstream urine sample.

TRIAL REGISTRATION: International Standard Randomised Controlled Trial Number (ISRCTN) 84676764: Feasibility of conducting a randomised controlled trial (RCT) comparing invasive and non-invasive urine sampling techniques in children under 16 years old with a suspected urinary tract infection 1.