Upper Urinary Tract Culture Positivity in Obstructive Ureterolithiasis—Clinical Severity, Inflammatory Biomarkers, and Early Risk Assessment

Background/Objectives: Obstructive ureterolithiasis complicated by infection may progress rapidly to systemic deterioration, while microbiological confirmation is generally unavailable during initial assessment. This study evaluated the association of admission procalcitonin (PCT), National Early Warning Score 2 (NEWS2), and routine urinary parameters with positive upper urinary tract culture in patients requiring urgent urinary decompression.

Methods

This retrospective single-center observational study included 240 adults admitted with obstructive ureterolithiasis who underwent upper urinary tract decompression by ureteral stenting or percutaneous nephrostomy. Demographic, clinical, laboratory, and urinary parameters obtained at admission were compared according to upper urinary tract culture status. Factors associated with culture positivity were assessed using univariable and multivariable logistic regression. Four clinically defined models were compared: a reference model containing WBC, CRP, urinary nitrites, and proteinuria; models separately adding PCT or NEWS2; and a complete model containing both. Discrimination was compared using AUCs and the DeLong test, while model fit was assessed using likelihood-ratio tests. Internal validation was performed using 1000 bootstrap resamples.