• An abnormally increased sodium concentration in the blood.
  Human Phenotype Ontology (HPO)
  The Human Phenotype Ontology Project, 2025
• Excessive amount of sodium in the blood. (Dorland, 27th ed)
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2025
• A disorder characterized by laboratory test results that indicate an elevation in the concentration of sodium in the blood.
  Common Terminology Criteria for Adverse Events
  U.S. National Institutes of Health, 2021
• Hypernatremia is a serum sodium concentration > 145 mEq/L (> 145 mmol/L). It implies a deficit of total body water relative to total body sodium caused by water intake being less than water losses. A major symptom is thirst; other clinical manifestations are primarily neurologic (due to an osmotic shift of water out of brain cells),...
  Merck Manuals
  Merck & Co., Inc., 2025
• Hypernatremia is a common electrolyte problem and is defined as a rise in serum sodium concentration to a value exceeding 145 mmol/L. It is strictly defined as a hyperosmolar condition caused by a decrease in total body water (TBW) relative to electrolyte content.
  Medscape
  WebMD, 2025
• An electrolyte imbalance consisting of a rise in serum sodium concentration. Hypernatremia is defined as a serum sodium concentration of >145 mEq/L (normal serum sodium concentration is in the range of 135-145 mEq/L). Severe hypernatremia has been defined as a serum sodium concentration of >152 mEq/L, or >160 mEq/L in some studies;...
  Epocrates
  Athenahealth, Inc., 2019