Urine Production Rate Calculator
Calculation Results:
Absolute Rate: mL/hour
Weight-Adjusted Rate: mL/kg/hr
Clinical Status:
Understanding Urine Production Rates
Urine production rate, often referred to as "urine output," is a critical clinical metric used by healthcare professionals to assess kidney function and a patient's fluid balance. It measures the volume of urine produced over a specific period, typically normalized to the patient's body weight for accuracy.
How to Calculate Urine Production Rate
The calculation is performed in two steps. First, you determine the total rate per hour, and then you adjust that figure based on the patient's weight.
Formula 1 (Rate per Hour): Total Volume (mL) ÷ Time (Hours) = mL/hr
Formula 2 (Weight Adjusted): Rate per Hour (mL/hr) ÷ Body Weight (kg) = mL/kg/hr
Clinical Interpretation of Results
For adults, the following ranges are generally used to interpret urine output:
- Normal: 0.5 to 1.5 mL/kg/hr (indicates adequate renal perfusion).
- Oliguria: Less than 0.5 mL/kg/hr (may indicate dehydration, kidney injury, or shock).
- Anuria: Less than 50 mL total over 24 hours (clinically urgent absence of urine).
- Polyuria: Greater than 3.0 mL/kg/hr (excessive urine production, possibly due to diabetes or high fluid intake).
Calculation Example
Suppose a patient weighing 80 kg produces 1,200 mL of urine over a 12-hour collection period.
- Calculate mL/hour: 1,200 mL ÷ 12 hours = 100 mL/hr.
- Calculate mL/kg/hr: 100 mL/hr ÷ 80 kg = 1.25 mL/kg/hr.
- Result: This patient falls within the "Normal" range.
Disclaimer: This calculator is for educational purposes only and should not be used as a substitute for professional medical advice or diagnosis. Always consult with a qualified healthcare provider regarding renal health.