Question

Polyuria is defined as urine output greater than?

• A. 70 ml/kg/day
• B. 60 ml/kg/day
• C. 50 ml/kg/day
• D. 40 ml/kg/day

Hint:

The weight-based cut-off is urine output above 50 ml/kg/day.

Answer 1

The Correct Option is C

Step 1: Translate the term. Polyuria simply describes passing too much urine, and the cut-off is usually expressed per kilogram of body weight per day.
Step 2: The recognised threshold is a daily output above 50 ml for every kilogram of body weight, so anything exceeding 50 ml/kg/day qualifies as polyuria.
Step 3: For a typical adult this works out to more than roughly 3 litres a day, the figure clinicians commonly use at the bedside, and the weight-based version simply scales that to body size.
Step 4: The higher numbers (70 and 60 ml/kg/day) sit above the true limit and the lower number (40 ml/kg/day) sits below it, so none of them is the defining value. The correct figure is 50 ml/kg/day. \[\boxed{50\ \text{ml/kg/day}}\]