Determination of low or high potassium can be based on blood biochemical tests such as blood potassium concentration. 1. Blood potassium concentration: The concentration of serum potassium in normal people should fluctuate between 3.5 and 5.5 mmol/L. Hypokalemia usually refers to a blood potassium concentration below 3.5 mmol/L, while hyperkalemia usually refers to a blood potassium concentration above 5.5 mmol/L. 2. Hyperkalemia is caused by prolonged inadequate intake of potassium (e.g., patients with prolonged fasting); excessive loss of potassium (e.g., severe vomiting, sustained gastrointestinal decompression, enterocutaneous fistulae, etc.); and extracellular transfer of potassium into the cells (e.g., alkalosis, excessive insulin administration). 3. Hyperkalemia is caused by excessive potassium intake (e.g., large amounts of stored blood); decreased potassium excretion (e.g., renal failure); and transfer of intracellular potassium to extracellular (e.g., acidosis, hypoxia). 4. The treatment of hyperkalemia mainly focuses on actively treating the primary disease and replenishing potassium, while the treatment of hyperkalemia firstly stops the drugs that elevate blood potassium, clarifies the etiology of hyperkalemia, and actively treats the primary disease. If the blood biochemistry examination shows low or high potassium, the patient should consult a doctor in time to make a clear diagnosis, and carry out treatment according to the doctor’s instruction, so as to avoid delaying the condition.