The seven electrolyte tests are used to check the levels of serum potassium, sodium, chloride, calcium, phosphorus, magnesium and iron. The role of the seven electrolyte tests is mainly to maintain normal cellular metabolism, to maintain the acid-base balance of the body, and is also the basis for normal neuromuscular stress. The clinical significance of each electrolyte is summarized below: 1. Serum potassium: Increase is seen in renal failure, shock, excessive potassium intake, etc. Decrease is seen in adrenocortical function. Decrease is seen in hyperadrenocorticism, severe vomiting, diarrhea, metabolic alkalosis. 2. Serum sodium: increase in anterior pituitary tumor, hyperadrenocorticism, severe dehydration. Decrease is seen in diabetes mellitus, adrenocortical insufficiency, vomiting, diarrhea and so on. 3. Serum chloride: elevated in excessive intake, dehydration, renal insufficiency, etc. Decreased in insufficient intake, diarrhea, etc. Decrease is seen in insufficient intake, diarrhea, emphysema, etc. 4. Serum calcium: increase in nodular disease, acute bone atrophy, hyperparathyroidism. Decrease in serum calcium can be seen in low calcium convulsions and other symptoms, mostly seen in insufficient intake and other conditions. 5. Serum phosphorus: increased in chronic nephritis uremia, hypoparathyroidism. Decrease can be seen in rickets, osteochondrosis, renal tubular lesions. 6. Serum magnesium: increase can be seen in hypothyroidism, severe dehydration; decrease can be seen in diarrhea, vomiting, hyperthyroidism. 7. Serum iron: increase can be seen in acute viral hepatitis, hepatic necrosis. Decrease can be seen in iron deficiency anemia, ulcer disease, hemorrhagic disease and so on. The role of electrolyte seven tests is very large, if the test results are abnormal, you need to consult a doctor in a timely manner, for the cause of the treatment, timely supplementation or to promote excretion.