The predictive value of serum C-reactive protein for spontaneous stone passage in patients with distal ureteric stones – an analytical cross sectional study.

Abstract

Objective: To determine and compare the frequency of spontaneous stone passage within 4 weeks in patients with 4-8 mm distal ureteric stones with normal baseline serum CRP ≤6 mg/L and raised baseline serum CRP >6 mg/L.” Study Design: Analytical Cross-sectional. Setting: Department of Urology and Renal Transplantation, Faisalabad Medical University, Allied Hospital-I, Faisalabad Pakistan. Period: November 2025 to April 2026. Methods: 110 individuals between the ages of 18 and 50 who had a single distal ureteric stone measuring 4 to 8 mm participated in the analytical cross-sectional study. Consecutive non-probability sampling was the method employed. Based on baseline serum CRP values, two patient groups were created: those with CRP ≤6 mg/L and those with CRP >6 mg/L at presentation. Standardised medical expulsive therapy, which includes tamsulosin 0.4 mg once daily, diclofenac as needed, and sufficient water intake, was prescribed to each patient. Together with a KUB X-ray and ultrasound KUB verified SSP at the four-week follow-up assessment. The frequencies of SSP and non-SSP were compared between the two groups using the chi-square test and the ideal CRP cut-off value was determined using receiver operating characteristic (ROC) curve analysis. Results: The average stone size was 6.06 ± 1.26 mm, and the average patient age was 35.27 ± 8.66 years. In all, 81 patients (73.6%) experienced spontaneous stone expuslion. Patients with a CRP level of ≤6 mg/L had a significantly greater SSP than those with a level of >6 mg/L (95.4% vs. 42.2%, p < 0.001). The ROC analysis’s area under the curve (AUC) of 0.945 (95% CI: 0.904-0.986, p < 0.001) demonstrated a high degree of prediction for the serum level of CRP. The ideal cut-off value for CRP levels for SSP prediction was determined to be ≤ 9.53 mg/L, with an 87.7% sensitivity and an 86.2% specificity. Conclusion: In individuals with 4–8 mm distal ureteric stones, the serum CRP level is a significant predictor of spontaneous stone passage. Lower CRP levels result in a much higher spontaneous passing rate. When incorporated into routine clinical examination, serum CRP levels may be helpful for improving patient stratification and assisting in the choice between conservative and interventional treatment choices.