Electrolytes are involved in most major metabolic functions in the body. Sodium, potassium and chloride are amongst the most important physiological ions and the most often assayed electrolytes. They are supplied primarily through the diet, absorbed in the gastrointestinal tract, and excreted via the kidneys.
Clinical aspects The human body contains about 50 mmol potassium per kg body weight. About 98 % of this is contained in the cells, only 2 % in the extracellular space. This concentration gradient between the intracellular and extracellular space is essential in order to maintain the membrane potential and the excitability of the cells. The daily requirement of 30 - 50 mmol potassium is satisfied by dietary intake, absorption takes place mainly in the small intestine. About 90 % of potassium excretion takes place via the kidneys and about 10 % with the faeces.
Disturbances of potassium homeostasis, in whichever direction, are relatively poorly compensated and can rapidly lead to life-threatening situations particularly with regard to cardiac function.
Potassium is the major intracellular cation and is critical to neural and muscle cell activity. Some causes of decreased potassium levels include reduced intake of dietary potassium or excessive loss of potassium from the body due to diarrhea, prolonged vomiting or increased renal excretion. Increased potassium levels may be caused by dehydration or shock, severe burns, diabetic ketoacidosis, and retention of potassium by the kidney.
Potassium measurements are used in the diagnosis and treatment of hypokalemia (metabolic alkalosis, metabolic acidosis or the absence of acid-base disturbances), hyperkalemia (overadministration of potassium, acidosis, or crush injuries), renal failure, Addison’s disease or other diseases involving electrolyte imbalance.
SI units Conversion Calculator. Convert Potassium (K) level to mmol/L, mEq/L . Clinical laboratory units online conversion from conventional or traditional units to Si units. Table of conversion factors for Potassium (K) unit conversion to mmol/L, mEq/L .