In the human organism approximately 50 mmol of potassium per kilogram can be found (98% of which is stored in cells, 2% extracellular). To guarantee membrane potential and cell excitability the concentration difference needs to be maintained. The required daily dose of potassium (30 – 50 mmol) is ingested with food and resorption mainly happens in the small intestine. Potassium is excreted through the kidney by 90% and through stool by 10%. Whenever the potassium household is imbalanced it cannot be compensated easily. Disturbance within the potassium metabolism, no matter whether deficiency or excess, can quickly lead to life-threatening states which primary affect the heart function.
The reagent agglutinates potassium ions and forms a stable, cloudy suspension. The degree of turbidity is measured at 700 nm with the photometer.