Disorders of calcium metabolism occur when the body has too little or too much calcium

Calcium

Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...

. The serum level of calcium is closely regulated within a fairly limited range in the human

Human

Humans are the only living species in the Homo genus...

 body.

The amount of biologically active calcium varies with the level of serum albumin

Serum albumin

Serum albumin, often referred to simply as albumin is a protein that in humans is encoded by the ALB gene.Serum albumin is the most abundant plasma protein in mammals. Albumin is essential for maintaining the osmotic pressure needed for proper distribution of body fluids between intravascular...

, a protein to which calcium is bound, and therefore levels of ionized calcium are better measures than a total calcium; however, one can correct a total calcium if the albumin level is known.

• A normal ionized calcium is 1.12-1.45 mmol/L (4.54-5.61 mg/dL).
• A normal total calcium is 2.2-2.6 mmol/L (9-10.5 mg/dl).
  • Total calcium of less than 8.0 mg/dL is hypocalcaemia
    Hypocalcaemia
    In medicine, hypocalcaemia is the presence of low serum calcium levels in the blood, usually taken as less than 2.1 mmol/L or 9 mg/dl or an ionized calcium level of less than 1.1 mmol/L or 4.5 mg/dL. It is a type of electrolyte disturbance...
    
    , with levels below 1.59 mmol/L (6 mg/dL) generally fatal.
  • Total calcium of more than 10.6 mg/dL is hypercalcaemia
    Hypercalcaemia
    Hypercalcaemia is an elevated calcium level in the blood. . It can be an asymptomatic laboratory finding, but because an elevated calcium level is often indicative of other diseases, a workup should be undertaken if it persists...
    
    , with levels over 3.753 mmol/L (15.12 mg/dL) generally fatal.

See also

• calcium metabolism
  Calcium metabolism
  Calcium metabolism or calcium homeostasis is the mechanism by which the body maintains adequate calcium levels. Derangements of this mechanism lead to hypercalcemia or hypocalcemia, both of which can have important consequences for health....
  
  
• Pseudohypoparathyroidism
  Pseudohypoparathyroidism
  Pseudohypoparathyroidism is a condition associated primarily with resistance to the parathyroid hormone. Patients have a low serum calcium and high phosphate, but the parathyroid hormone level is actually appropriately high...
  
  
• Milk-alkali syndrome
  Milk-alkali syndrome
  In medicine, milk-alkali syndrome, also called Burnett's syndrome in honour of Charles Hoyt Burnett, the American physician who first described it, is characterized by hypercalcemia caused by repeated ingestion of calcium and absorbable alkali...