Abstracts 51 P5-6: Figure 2 Patients and Methods: Notes of all females coded as having retention between the period 01/10/2014 - 30/09/2016 were analysed. Results: Single episode of retention. N=40. Most common causes are constipation, anaesthetic / medication use. 91% of these pass a TWOC on first attempt. 27 (60%) of women had imaging / cystoscopy with no findings. 3 (6%) had a pelvic mass on USS. UTI's only accounted for 3 (6%) of cases but can trigger acute on chronic retention, as can constipation. 9 women (19%) transpired to be chronic retainers, having failed their initial TWOC's. 78% of these women (n=7) had some form of imaging in the form of an USS +/- MRI spine and 88% (n=8) had a flexible or rigid cystoscopy yielding no new information. Recurrent episodes of retention. N =20. All 20 women had an USS or MRI, 50% had both modalities with no positive findings. 50% had cystoscopy +/- urethral dilatation with no effect / positive finding. 9 (45%) of women were deemed functional retainers after investigation. Conclusions: We propose the following algorithm for first presentation of retention: Recurrent retention These women undergo multiple investigations without positive findings, potentially contributing to their high