Purpose:The relationship between ureteral stent duration before percutaneous nephrolithotomy (PCNL) and infectious complications, admissions, imaging, and medical costs was evaluated.Materials and Methods:Patients who underwent PCNL within 6 months of ureteral stent placement were identified from commercial claims, categorized by time to treatment (0–30, 31–60, and >60 days), and followed 1-month post-PCNL. The effect of delayed treatment on inpatient admissions, infectious complications (pyelonephritis/sepsis), and imaging utilization was evaluated with logistic regression. A generalized linear model evaluated the effect of delayed treatment on medical costs.Results:Among 564 patients with PCNL and meeting the inclusion criteria (mean age 50; 55% female; 45% from South), mean (standard deviation) time to surgery was 48.8 (41.8) days. Less than half (44.3%;n= 250) underwent PCNL within 30 days of ureteral stent placement, 27.0% (n= 152) between 31 and 60 days, and 28.7% (n= 162) >60 days. Time to PCNL was significantly associated with inpatient admissions (>60vs≤30 days odds ratio [OR] 1.97, 95% confidence interval [CI] 1.29–3.01,p= 0.0016), infectious complications (>60vs≤30 days OR 2.43, 95% CI 1.55–3.81,p= 0.0001), imaging utilization (31–60vs≤30 days OR 1.56, 95% CI 1.02–2.38,p= 0.0383; >60vs≤30 days OR 2.01, 95% CI 1.31–3.06,p= 0.0012), and medical costs (31–60vs≤30 days OR 1.27, 95% CI 1.08–1.49,p= 0.0048; >60vs≤30 days OR 1.46, 95% CI 1.24–1.71,p< 0.0001).Conclusions:Compared with PCNL within 30 days, patients undergoing PCNL >30 days after ureteral stent placement had increased likelihood of infectious complications, resource use, and medical costs. These results may inform health care resource utilization and PCNL prioritization.