Because all calcium in the blood is stored in the plasma, blood calcium mainly refers to plasma calcium, and the main forms of plasma calcium are ionized calcium and bound calcium, both accounting for 50%. The blood calcium concentration is basically stable under the influence of several factors in the body, its normal value is in 2.25-2.75mmol/L, equivalent to 9-11mg/dl, the inorganic phosphorus in the blood is blood phosphorus, the main form of existence is inorganic phosphate, such as CaHPO4, Na2HPO4. normal adult blood phosphorus concentration is 0.97-1.61mmol/L, children are higher than The normal blood phosphorus concentration is 0.97-1.61 mmol/L in adults and 1.29-1.94 mmol/L in children, but it varies slightly from hospital to hospital, but is basically within this range.