Urine culture, stone culture, and procalcitonin: a triad for predicting the risk of infectious complications after mini-PCNL-results from a large, single-center series

Purpose: To evaluate association between postoperative serum procalcitonin (PCT) levels and infectious complications following mini-percutaneous nephrolithotomy (mini-PCNL), and to identify predictors of elevated PCT. Methods: We retrospectively analyzed 496 adult patients who underwent mini-PCNL for kidney stones (February 2020-March 2025). Patients were stratified into four groups based on postoperative fever occurrence and PCT levels (≤ 2.0 ng/ml vs. > 2.0 ng/ml): Group 1 (no fever, low PCT, n = 404), Group 2 (fever, low PCT, n = 10), Group 3 (no fever, high PCT, n = 65), and Group 4 (fever, high PCT, n = 17). Multivariable logistic regression analysis identified factors associated with PCT levels > 2.0 ng/ml. Results: Elevated PCT occurred in 82 patients (16.5%). Groups 3 and 4 had significantly higher rates of positive preoperative urine cultures (46.2% and 64.7%) compared to Groups 1 and 2 (6.2% and 30%, p < 0.001). Positive stone cultures were more frequent in Group 3 (50.8%). Median PCT level was higher in Group 4 [38.00 (13.10-87.70) ng/mL] compared with Group 3 [18.10 (8.60-54.0) ng/mL]. Major infectious complications (Clavien ≥ 3) occurred exclusively in Group 4, including one sepsis-related death. Multivariable analysis revealed that positive preoperative urine culture (OR 6.72 95% CI 3.20-14.14) and stone culture (OR 4.83 95% CI 2.34-9.81) were independent predictors of elevated PCT. Conclusions: Elevated PCT following mini-PCNL is associated with positive preoperative urine and stone cultures, regardless of fever presence. Several patients exhibit elevated PCT without clinical manifestation of infection, suggesting a subclinical infection. These findings support the integration of PCT for enhanced risk stratification and postoperative management following mini-PCNL.