STONE Score as a Triage Tool to Guide Computed Tomography of the Kidneys, Ureters, and Bladder (CT-KUB) Requests in Suspected Renal Colic: A Quality Improvement Initiative.

Introduction Urolithiasis is a frequent cause of emergency department (ED) visits, with computed tomography (CT) being the gold standard for diagnosis. Excessive imaging increases radiation exposure and healthcare costs. The STONE score is a validated clinical prediction tool, designed to estimate the probability of ureteric stones and reduce unnecessary imaging. Objective The main objective of this study is to evaluate the diagnostic accuracy of the STONE score in patients presenting with flank pain. Methodology This is a cross-sectional retrospective review conducted at the Shrewsbury and Telford Hospital NHS Trust (SATH), Shrewsbury, England, over a four-month period from April 1, 2023, to July 31, 2023. This quality improvement initiative reviewed 81 eligible ED patients who underwent computed tomography of the kidneys, ureters, and bladder (CT-KUB) for suspected ureteric stones. Demographic, clinical, laboratory, and imaging data were collected. STONE scores were calculated for all patients. Diagnostic performance was assessed using receiver operating characteristic (ROC) curve analysis. Results The mean age was 38.5 ± 16.1 years; 35 (43.2%) were male. Ureteric stones were confirmed in 15/19 (78.9%) high-risk, 9/45 (20%) moderate-risk, and 0/17 (0%) low-risk patients. The STONE score yielded an area under the curve (AUC) of 0.879, with a sensitivity of 91.7% and a specificity of 66.7%. Alternative diagnoses included gallbladder stones, appendicitis, cystitis, diverticulitis, hydronephrosis, renal angiomyolipoma, polycystic kidney disease (PCKD), pyelonephritis, and small bowel obstruction (SBO). Conclusion The STONE score demonstrates good diagnostic accuracy, particularly in high-risk patients, and may help reduce unnecessary CT imaging and radiation exposure in the ED.