Serum potassium

The potassium in the human body mainly comes from food. Over 90% of the potassium in food is absorbed in the intestine in a short time, and 90% of the potassium absorbed into the blood is excreted from the kidney within 4h. Most potassium ions (98%) exist in the cells, and a small amount is in the extracellular fluid, and the concentration is constant. Tissue cells contain an average of K + 150mmol / L, red blood cells contain K + about 105mmol / L, and serum contains K + about 4-5mmol / L. Potassium ions in the body are constantly exchanged between cells and body fluids to maintain dynamic balance. Potassium is the main cation that maintains the physiological activities of cells, and plays an important role in maintaining the body's normal osmotic pressure and acid-base balance, participating in sugar and protein metabolism, and ensuring the normal function of neuromuscles.