Trial design: Pilot feasibility trial. Methods: Participants: adults attending the Outpatient Urology Clinic, having a long-term in-dwelling urinary catheter and have the mental capacity to consent. Consent for the donation of the urinary catheter and drainage bag were gained at the Urology Clinic, Royal United Hospital (RUH) Bath, alongside a quality-of-life questionnaire. Interventions: there was no direct intervention to the participants, the trial was to test the functionality of the diagnostic sensor, there was no change to the participant's medical care. Objectives: recruitment of 48 participants to donate catheter and drainage bags (including re-recruits); assess the functionality of the sensor to predict impending catheter blockage in human urine; assess the functionality to release at pH > 7; and assess the microbiological profile of the patients with long-term catheters. Outcome: determination of whether the participant had a blockage event 3 weeks post catheter change, and whether this matched with the result from the sensor. Measurements of the participant's urine to assess whether the sensor could detect human urine at a pH > 7. Determine the microbial species present in the drainage bag of the participants. Results: Recruitment: received 35 samples from 28 individuals. Outcome: two participants reported blockage events which were successfully detected by the sensor, however the sensor also predicted blockage in participants that did not block within the 3-week report time period, sensitivity = 100%, specificity = 58.06%. The functionality of the sensor to detect urine above pH > 7 had a sensitivity = 78.75% and a specificity = 96.77%, which gave a p = 2.06x10^-24 (χ^2 test). Inclusion of the maintenance solution prescribed to the blocked catheter group, to test the predictability of the sensor, gave a sensitivity = 100%, and a specificity = 62.95%, p = 0.029 (Fisher Exact test). Microbiological analysis indicated that Proteus spp. and Pseudomonas spp. were the most commonly isolated microbes. Harms: No adverse events. Conclusions: The sensor can predict participants more prone to catheter blockage, and it is accurate in detecting urine with a pH >7. Owing to the small sample number of this trial, the results are not statistically powered. However, the data can be used to improve the design of the sensor and inform the design of a larger, randomized clinical trial. Trial registration: Trial was ethically approved by the Research Ethics Committee (REC) number: 20/LO/0094. Integrated Research Application System (IRAS) number: 261095. Funding: trial was funded by the Urology Foundation and an IAA seed grant, University of Bath.

The authors have declared no competing interest.

Trial was funded by the Urology Foundation and an IAA seed grant, University of Bath.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Research Ethics Committee of Health Research Authority, National Health Service, UK, gave ethical approval for this work (REC number: 20/LO/0094).

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All data produced in the present study are available upon reasonable request to the authors