This page deals with the interpretation of blood values that can be collected during a blood test.


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

While sodium is mainly found outside the cells (in the so-called intercellular space), potassium is found inside the cell. Therefore, for example, the potassium content in a red blood cell (erythrocyte) is 25 times higher than in blood serum (blood fluid without cells). The potassium content of our body is kept constant by various regulatory mechanisms.

Potassium is absorbed through food in the small intestine and from divorce through the kidneys. The kidney can excrete about 1 mmol/kg body weight in 24 hours with the urine. In addition to potassium intake, regulation is also subject to various hormones (for example, glucocorticoids (insulin, glucagon) and mineralocorticoids such as cortisone), but also to the acid-base status (proportion of acids and alkalis) in the body.

Determination methods

The potassium value is determined in blood plasma or blood serum. A blood sample must be taken for this. Other electrolytes in the blood can also be determined.

Standard values of potassium

Potassium values that are considered normal in an adult healthy person are in the range of 3.6 to 4.8 mmol/l. More about potassium values at our partner. An increase of potassium concentrations in serum or plasma above 5.0 mmol/l is medically called hyperkalemia.

A too high potassium level in the blood is most frequently manifested by symptoms in the heart or nerves. Common symptoms are numbness, numbness, but also muscle twitching. Cardiac arrhythmias occur in the heart, which can also be detected by changes in the ECG. The causes of hyperkalemia can be his:

  • Incorrect blood collection (if the upper arm is congested for too long, there is a lack of oxygen, especially if the fist is opened and closed during the blood collection, which causes the potassium from the cell to overflow into the blood plasma and falsifies the actual value) (if the blood cells (white blood cells and red blood cells) are not separated from the blood plasma within one hour, potassium is released from the cells, which also causes a fake high potassium value)
  • Pronounced muscle injury (release of potassium from the cells)
  • Tumor disease (release of potassium from dying tumor cells)
  • Renal insufficiencyKidney failure (lack of potassium excretion)
  • Drugs (ACE inhibitors (blood pressure medication), antibiotics (for example Cotrim® = medication for cystitis), NSAIDs (for example ibuprofen), potassium-sparing diuretics such as spironolactone (Aldactone®), amiloride or triamterene