Diagnostic performance of intraoperative urine dipstick testing during ureteroscopy: association with culture positivity and severe infection.

Ureteroscopy (URS) is a widely performed procedure for urinary stone disease, yet infectious complications, including sepsis, remain a concern despite negative preoperative urine cultures. Intraoperative urine dipstick testing offers a rapid point-of-care assessment, but its diagnostic performance for predicting culture positivity and severe infection at different sampling sites during URS remains unclear. In this retrospective, single-center study, 238 patients undergoing URS were included. Paired urine dipstick and culture samples were obtained from bladder urine, intraoperative pelvic urine, and post-laser pelvic urine. Dipstick positivity was defined using two criteria: leukocytes and/or nitrites (OR definition) and leukocytes and nitrites (AND definition). Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) with 95% confidence intervals were calculated for predicting culture positivity. Receiver operating characteristic (ROC) curve analysis was performed, including a composite dipstick score (0-2). Severe postoperative infection was assessed as a secondary exploratory outcome. Culture positivity ranged from 18.4% (bladder) to 22.9% (intraoperative pelvic urine). Using the OR definition, pooled sensitivity was 80.5% and specificity 47.6%, whereas the AND definition yielded lower sensitivity (43.8%) and higher specificity (86.4%). Diagnostic performance varied by sampling site, with intraoperative pelvic urine demonstrating the most balanced metrics. ROC analysis showed moderate discriminative performance, with the highest AUC observed for pelvic urine sampled prior to laser fragmentation (AUC 0.723, 95% CI 0.646-0.801). For severe infection (4.2%), dipstick testing demonstrated low sensitivity (30%), and this analysis was considered exploratory. Intraoperative urine dipstick testing demonstrates moderate diagnostic performance for predicting culture positivity during URS, with results influenced by sampling site and positivity definition. Pre-laser pelvic sampling provides the most informative results. A negative intraoperative dipstick, particularly from pre-laser pelvic urine, may help identify patients at lower likelihood of culture positivity; however, the test remains insufficient to guide antimicrobial or postoperative decision-making in isolation. Further prospective studies are required to validate its role in perioperative risk stratification.