Clinical Significance

The majority of calcium in the body is present in bones.  The remainder of the calcium is in serum and has various functions.  For example, calcium ions decrease neuromuscular excitability, participate in blood coagulation, and activate some enzymes.

As part of the BMP and CMP, abnormal calcium levels lead to other underlying causes.  Hypercalcemia may be seen in cancer, especially bone cancer, hypervitaminosis D, kidney transplant, multiple myeloma, tuberculosis, and in hyperparathyroidism.  Long-term lithium therapy may cause hyperparathyroidism, with resulting hypercalcemia.

Hypocalcemia can be seen in malabsorption, alcoholism, hypoalbuminemia, hypoparathyroidism, renal insufficiency and acute pancreatitis.  Low dietary intake of calcium, vitamin D deficiency, may be other causes.