Hypocalcemia in the elderly

Normal human serum total calcium is fairly constant, 2.25 ～ 2.75mmol / L, which is higher in children. Calcium in plasma and body fluids mainly exists in two ways: combined calcium and free calcium. The former is mainly combined with albumin and a small amount with organic acids, such as calcium citrate, calcium lactate, calcium phosphate, and the like. The constant exchange of free calcium and bound calcium is in a dynamic equilibrium, which is mainly affected by pH. Free calcium (Ca2 +) increases in acidemia and the opposite occurs in alkalemia. In addition, a certain product is maintained between blood calcium and blood phosphorus concentrations, that is, [Ca] times; [P] = 350 ～ 400mg / L. Only free calcium really has the physiological function of calcium. Those with serum calcium below 2.2mmol / L are said to be hypocalcemia.