PTH stands for parathyroid hormone. It is a protein hormone released by the parathyroid gland.
The parathyroid glands are located in the neck, near or attached to the back side of the thyroid gland. Parathyroid hormone controls calcium, phosphorus, and vitamin D levels in the blood and bone.
Release of PTH is controlled by the level of calcium in the blood. Low blood calcium levels cause increased PTH to be released, while high blood calcium levels block PTH release.
A laboratory test can be done to measure the amount of PTH in your blood.
Parathormone; Parathormone (PTH) intact molecule; Parathyroid hormone
A blood sample is needed. For information on how this is done, see: Venipuncture
Ask your health care provider if you should stop eating or drinking for some period of time before the test. Most often, you will not need to fast or stop drinking.
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Your health care provider may order this test if:
Normal values are 10 - 55 picograms per milliliter (pg/mL). To help understand whether your parathyroid hormone levels are normal, your health care provider will measure your blood calcium at the same time.
The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different specimens. Talk to your doctor about the meaning of your specific test results.
Parathyroid hormone levels above 55 picograms per milliliter (pg/mL) are considered to be high. These higher levels may be caused by:
Lower-than-normal levels may occur with:
Other conditions under which the test may be performed:
Bringhurst FR, Demay MB, Kronenberg HM. Hormones and disorders of mineral metabolism. In: Kronenberg HM, Melmed S, Polansky KS, Larsen PR, eds. Williams Textbook of Endocrinology. 12th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 28.