Genitourinary System Disorders Practice Test 2026 - Free Genitourinary Disorders Practice Questions and Study Guide

Uric acid stones form in acidic urine because the solubility of uric acid is highly pH-dependent. In an acidic environment, uric acid remains largely nonionized and has low solubility, so it tends to crystallize and aggregate into stones. When urine is alkaline, uric acid is converted to urate, which is much more soluble, making stone formation less likely. Neutral urine isn’t as conducive to uric acid crystallization as acidic urine, and high urine calcium points toward calcium-based stones rather than uric acid stones. So the acidic urine context best explains why uric acid stones form.