Intracellular Water (ICW)

The fluid present inside the body’s cells. Water is needed inside the cell to hold water soluble nutrients. Two thirds of the Total Body Water (TBW) in an average healthy person should consist of ICW.

Extracellular Water (ECW)

The fluid present outside the body’s cell walls, for example in blood plasma. This water also helps remove waste from inside the cells. Approximately one third of Total Body Water (TBW) in an average healthy person should consist of ECW.

 For more information on why it is important to monitor intra and extracellular water, please read:

Why is it important to measure Intracellular and Extracellular water?