What is the acceptable variance when recording urinary output in milliliters?

• A. +/- 5
• B. +/- 10
• C. +/- 25
• D. +/- 50

Answer: (C)

When measuring urinary output, there’s natural variability in how precisely you can capture the exact milliliters due to the measuring tool, how the urine is transferred, and when you read the level. Because of these small, real-world differences, the acceptable margin is plus or minus 25 milliliters. This level keeps the data useful for tracking fluid balance and kidney function without demanding impossible precision in everyday care.

Smaller tolerances, like plus or minus 5 or 10 mL, would be hard to achieve consistently in routine situations and could lead to frequent record corrections. A much larger tolerance, such as plus or minus 50 mL, would make the urine output data too imprecise to base clinical decisions on. So plus or minus 25 mL strikes a practical balance between accuracy and feasibility, and you’d document the total as recorded, along with any factors that might affect the measurement per your facility’s policy.