Extravascular Fluid (EVF)

Extravascular fluid refers to all fluid outside the blood vessels, constituting approximately 48-58% of body weight[1]. It includes intracellular fluid (fluid within cells), interstitial fluid (fluid surrounding cells in tissues), and transcellular fluid (fluid in specialized body cavities)[1][3]. The extracellular fluid (ECF), which is part of extravascular fluid, accounts for about one-third of total body water[3][6]. Interstitial fluid provides the immediate microenvironment that allows for movement of ions, proteins, and nutrients across cell barriers[3]. This fluid is continuously refreshed by blood capillaries and recollected by lymphatic capillaries[3]. Extravascular fluid generally has a high concentration of sodium and low concentration of potassium, contrasting with intracellular fluid which has high potassium and low sodium concentrations[5]. The movement of fluid between vascular and extravascular compartments is regulated by hydrostatic pressure gradients, with excess interstitial fluid being drained by the lymphatic system[6].

Other names

Body fluid outside blood vesselsNon-vascular fluid

Not applicable