Investigating 24-Hour Urine Expected Ranges of Non-Kidney Stone Formers: an EAU Endourology Research Group Systematic Review and Meta-Analysis

The study investigated expected ranges of 24-hour urine values in healthy adults without kidney stone disease. The analysis included 72 articles with a total of 10,284 participants. Researchers determined expected ranges for various urine components, such as volume 1.0-2.5 liters, calcium 1.9-6.2 mmol/24 h, and creatinine 12.2-16.3 mmol/24 h in men. Six of the derived ranges (pH, oxalate, magnesium, sulphate, urate, and creatinine) were consistent with existing reference ranges. The main limitation was high heterogeneity between studies and variability in laboratory methods. This first meta-analysis provides evidence for characterizing expected ranges of 24-hour urine collections.