The normal value of blood phosphorus is 1.1-1.3 mmol/L, and 1.3-2.3 mmol/L for infants. checking blood phosphorus is the same as checking blood sodium and potassium, just draw blood from your arm and check your serum electrolytes. Most of the phosphorus in the body is in the form of calcium phosphate, which is found in the bones and teeth, and only a small amount is found outside the bones and teeth. Phosphorus in the blood makes up only a small fraction of the body’s phosphorus, and age and season can affect the level of blood phosphorus. Children have higher levels of growth hormone in their bodies because of the need for growth and development, and therefore, higher blood phosphorus levels. Blood phosphorus levels are also higher in summer than in winter due to the effects of ultraviolet light, which is more intense. In addition, there is a relationship between blood phosphorus and calcium concentrations. The product of blood phosphorus and blood calcium concentrations in normal people is 36-40 (note: the unit of concentration here is mg/dl, not mmol/L, so convert it).