What urine output target is recommended to prevent nephrolithiasis?

• A. >600 mL/day
• B. >400 mL/day
• C. >1200 mL/day
• D. >2000 mL/day

Answer: (C)

Increasing urine volume helps prevent nephrolithiasis by diluting urine and lowering the concentration and supersaturation of stone-forming substances such as calcium, oxalate, uric acid, and cystine. The target of keeping urine output above about 1.2 liters per day provides enough dilution to reduce crystallization risk while remaining realistically achievable for many patients. Lower urine outputs leave urine more concentrated and higher outputs (around 2 liters daily) can be beneficial but aren’t always necessary or feasible in every situation. So, aiming for greater than 1.2 liters per day is the best-supported balance among the options presented.