Bone Disease Family

Our next two tests measure the risk of developing renal bone disease.

The first is called the parathyroid hormone (PTH) test. Your parathyroids are four tiny glands in your neck. Their job is to make PTH when your calcium levels fall. PTH helps you absorb calcium from what you eat and drink. High phosphate levels lead to high PTH.

Levels of intact PTH (iPTH) are measured, because high levels mean your glands may be getting bigger and making too much PTH. Your body tries to shut off the glands by pulling calcium out of your bones. If this goes on too long, your bones can become frail and may break easily.

Calcium-phosphorus product (Ca x P) is not really a test, but a number that is calculated by multiplying your serum calcium level by your serum phosphorus level. For example, if your calcium is 9.0 and your phosphorus is 6.5, your calcium-phosphorus product would be 58.5. Doctors keep track of this number because it is a good way to measure your risk of developing calcium phosphate crystals. These sharp crystals can form in soft tissues and joints, causing tissue damage, loss of limbs, and even death. This problem is very rare, but more likely in people who have diabetes.