Detection of Ureteric Calculi on Computed Tomography of the Kidneys, Ureters, and Bladder (CT KUB) in an Outpatient Population

Renal colic is an acute urological presentation that accounts for many attendances to the emergency department and urology service in the UK.Given the severe nature of the pain, renal colic typically presents acutely to secondary care.However, the urology service in University Ayr Hospital (UHA) receives a significant number of outpatient referrals from primary care with suspected renal colic.Standard practice in UHA currently is to vet these referrals directly to an urgent outpatient computed tomography of the urinary tract (kidney, ureter, and bladder) (CT KUB).This project aimed to assess the detection rate of CT KUB in detecting ureteric stones in patients referred as an outpatient with suspected renal colic.A retrospective cohort study was performed using data collected from outpatient referrals to the urology service in the University Hospital Ayr from August 2023 to August 2024.Information was gathered from Clinical Portal regarding the history, examination, and investigations performed in primary care, alongside the results of CT KUB.A total of 173 referrals with suspected renal colic were vetted straight to CT KUB.Twelve (6.9%) patients had ureteric calculi, and 35 (20.2%) had renal calculi.Six patients with ureteric calculi and four patients with renal calculi had their calculi managed with an operation.Many patients were referred without prior blood tests, ultrasound imaging, or urinalysis performed.These results highlight the need for a new pathway for the outpatient investigation of suspected renal colic, given the low detection rate of ureteric calculi on CT KUB in outpatient settings.