• Abnormally decreased volume of circulating fluid (plasma) in the body.
  CRISP Thesaurus
  National Institutes of Health, 2006
• An abnormally low circulating blood volume.
  U.S. FDA Glossary
  U.S. Food & Drug Administration, 2021
• An abnormally low volume of blood circulating through the body. It may result in hypovolemic shock (see SHOCK).
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2025
• An decrease in the amount of intravascular fluid, particularly in the volume of the circulating blood.
  Human Phenotype Ontology (HPO)
  The Human Phenotype Ontology Project, 2025
• Too little fluid in the blood.
  NICHD Pediatric Terminology
  U.S. National Cancer Institute, 2021
• Volume depletion, or extracellular fluid (ECF) volume contraction, occurs as a result of loss of total body sodium. Causes include vomiting, excessive sweating, diarrhea, burns, diuretic use, and kidney failure. Clinical features include diminished skin turgor, dry mucous membranes, tachycardia, and orthostatic hypotension. Diagnosis is...
  Merck Manuals
  Merck & Co., Inc., 2025
• Volume depletion is a reduction in extracellular fluid volume that occurs when salt and fluid losses exceed intake on a sustained basis. It may result from renal losses (diuresis) or extrarenal losses (from the gastrointestinal tract, respiratory system, skin, fever, sepsis, or third-space sequestration). Without proper assessment and...
  Epocrates
  Athenahealth, Inc., 2019