Intravascular volume status
In medicine, intravascular volume status refers to the volume of blood in a patient's circulatory system, and is essentially the blood plasma component of the overall volume status of the body, which otherwise includes both intracellular fluid and extracellular fluid. Still, the intravascular component is usually of primary interest, and volume status is sometimes used synonymously with intravascular volume status.
It is related to the patient's state of hydration, but is not identical to it. For instance, intravascular volume depletion can exist in an adequately hydrated person if there is loss of water into interstitial tissue (e.g. due to hyponatremia or liver failure).