Hypercalcemia

Hypercalcemia refers to the abnormal increase of serum ionic calcium concentration. Since total calcium is usually measured instead of ionic calcium, we must pay attention to the factors affecting ionic calcium. Serum albumin concentration is the most important factor in clinic, because albumin is the main calcium binding protein in the blood circulation. In the case of severe decrease of serum albumin (such as in patients with malignant tumors), the normal total serum calcium concentration actually represents the abnormally increased ionic calcium concentration. PH also affects the combination of serum calcium and protein. Alkalosis can reduce the concentration of ionic calcium and acidosis can increase it. When the calcium entering the extracellular fluid (intestinal bone) exceeds the discharged calcium (intestine and kidney), hypercalcemia occurs, and the blood calcium concentration is higher than 2.75mmol/l.