• Metabolic pathways
• Acid-base balance
• Energy transport

Most (85%) phosphorus is bound with calcium in the bones. Most of the rest is found within cells. Some phosphorus is found in the blood, in the form of phosphates or esters.

Phosphorus is drawn into the cells with glucose. Thus, whenever a significant glucose load is imposed (like eating a big meal), serum phosphorus levels will temporarily fall.

Phosphorus is balanced with calcium:

• Whatever makes calcium go up, usually makes phosphorus go down
• Whatever makes calcium go down, usually makes phosphorus go up.

Phosphorus levels may rise in the presence of:

• Renal failure
• Hypoparathyroidism
• Low calcium levels
• Addison's disease
• Excessive alkali intake

Phosphorus levels may fall in the presence of:

• Hyperparathyroidism
• Elevated calcium levels
• Vitamin C deficiency
• Hyperglycemia
• Hemolysis

Normal Values*

*These are general values taken from a variety of sources. The actual normal values may vary from lab to lab and from one type of testing protocol to another.