What is parathyroid hormone (PTH)?

PTH controls how much calcium is in your blood and bones. Your body's levels of calcium, vitamin D and phosphorus all need to be in balance. If they are out of balance (meaning one is higher or lower), your parathyroid glands make more PTH to try to "fix" the balance. For example:

• If phosphorus levels in your blood are too high, calcium levels are lower – they are not in balance.
• To fix the balance, your parathyroid glands make more PTH.
• More PTH pulls calcium from your bones to raise the level of calcium in your blood.

There are 3 types of hyperparathyroidism:

• Primary: One or more of your parathyroid glands are larger than normal, which causes them to make too much PTH. This is the most common type of hyperparathyroidism.
• Secondary: This is most common in people with kidney failure.
• Tertiary: This can happen in people after they get a kidney transplant.

Chronic kidney disease patients are at risk of developing secondary and tertiary hyperparathyroidism. So regular monitoring of blood levels of calcium, phosphorus and parathyroid hormone are important.