# Volume of Distribution of Urea Calculation

According to the urea kinetic model it is considered that the urea distribution volume (V) is that of body water, and that it is distributed in only one compartment. Since the V value is different to measure, it is normal to use 58% of body weight, in spite of the fact that it may range from 35 to 75%.

#### Equations Used for Calculation of Volume of Distribution of Urea

• VDU Females = (0.1069 × Height) + (0.2466 × Weight) - 2.097
• VDU Males = 2.447 - (0.09516 × Age) + (0.1074 × Height) + (0.3362 × Weight)

For example,

If the height = 170 cm; Weight = 70 kg & Age = 30 years;

For females, VDU = 33.34 L

For males, VDU = 41.38 L

An accurate estimate of volume of distribution of urea (VDU) is critically important to guide the prescription of therapy and the quantification of delivered dialysis dose in patients with chronic and acute renal failure (ARF). While Vurea has been shown to be substantially the same as total body water (TBW) in other patient populations, this relationship has not been adequately studied in detail in ARF patients.

Note: Urea volume of distribution (VDU) exceeds total body water in patients with acute renal failure.