Parathyroid Hormone (PTH)

Hormones are chemical messengers in your bloodstream. They control the actions of certain cells or organs. PTH controls the level of calcium in your blood. Calcium is one of the most important minerals in your body. Most of it is stored in your bones and teeth. Having the right amount of calcium in your blood is important for your nerves, muscles, and heart to work properly.

If your calcium blood levels are too low, your parathyroid glands will release just enough PTH into your blood to return your calcium levels to normal. When your calcium blood levels return to normal, your parathyroid glands stop making PTH and your blood PTH levels decrease.

Many health conditions can cause abnormal PTH levels. To understand what your PTH test results mean, your provider will consider the results of other tests, especially a blood calcium test. Your symptoms, medical history, and family history will also be considered.

If your PTH level is higher than normal, it's called hyperparathyroidism. The type you have generally depends on your blood calcium level.

Secondary hyperparathyroidism is high PTH levels with low blood calcium levels. Your parathyroid glands are working correctly by making extra PTH to try to increase your blood calcium. It's likely that a problem outside of your parathyroid glands is preventing your blood calcium levels from increasing.

Your provider will probably order more tests to find out what's causing your low blood calcium.