Our user-friendly TBW Deficit Calculator helps healthcare professionals and individuals understand the estimated excess free water volume that contributes to hyponatremia (low serum sodium). By accurately assessing the difference between your current and target sodium levels, this tool provides a crucial estimate for fluid management planning. Quickly determine the liters of water that need to be accounted for to normalize sodium levels effectively.
Formula:
The estimated Total Body Water (TBW) Deficit (or Free Water Excess) is calculated using the following formula:
Water Excess (L) = TBW (L) × (1 - (Current Serum Na (mEq/L) ÷ Target Serum Na (mEq/L)))
Where:
- TBW = Total Body Water in Liters
- Current Serum Na = Patient's current serum sodium level in mEq/L
- Target Serum Na = Desired serum sodium level in mEq/L
- TBW (L) = Body Weight (kg) × TBW Factor
TBW Factor: Approximately 0.6 for adult men, and 0.5 for adult women. This factor represents the proportion of body weight that is water.