This page deals with the interpretation of blood values that can be obtained from a blood test

Synonyms in a broader sense

  • Hypernatremia
  • Hypernatremia
  • Common salt
  • NaCl


Sodium belongs to the vital electrolytes (salts). Many important metabolic processes are regulated by sodium. Sodium forms a pair of antagonists in our body with potassium.

While sodium is mainly found outside the cells (in the so-called intercellular space), potassium is found inside the cell. The sodium content of our body is kept constant by various regulatory mechanisms. Sodium is actively pumped out of the cell in exchange for potassium (Na-K-ATP ́ase).

Sodium is absorbed through food in the small intestine and excreted through the kidneys. The total sodium content of the body is kept very constant within narrow limits. Sodium is strongly osmotic.

In simple terms, this means that sodium can attract water. This phenomenon is known from table salt (NaCl), which attracts water if it is not stored dry. Sodium belongs in our body accordingly. Larger amounts of table salt ingestion will attract “water” and as a result, thirst will develop.

Determination method

The sodium level is determined in blood plasma or blood serum. A blood sample is necessary for this. Other electrolytes in the blood can also be determined.

Standard values

Values that are considered normal in an adult healthy person are in the range of . Normal values of sodium in the blood: 135 to 145 mmol/l

Blood value increase

An increase in sodium concentrations in serum or plasma greater than 145 mmol/l is medically called hypernatremia. Symptoms usually only occur at sodium concentrations of more than 150 mmol/l. Sodium values of over 160 mmol/l can lead to life-threatening situations.

In most cases, hypernatremia is triggered by a lack of water. The consequences of hypernatremia are: Causes of hypernatremia can be

  • Disturbed consciousness
  • Restlessness
  • Excitability
  • Muscle tremor
  • Muscle cramps
  • Coma
  • Water loss, for example through heavy sweating
  • Diabetes insipidus Diabetes insipidus is a disturbance of the water from divorce by a hormone (ADH = anti-diuretic hormone). It can be a disorder of the formation of the hormone in the brain (primary type) or a reduced responsiveness of ADH at the kidney (secondary type). You can find more information on this topic at: diabetes insipidus
  • Disturbance of the feeling of thirst Such disturbances can be caused by benign or malignant brain tumors, but also by brain and skull injuries.