PTH
Meaning of PTH: PTH is a hormone that raises blood calcium by acting on bone, kidney, and the intestine, with abnormal levels signaling gland disease.
Definition of PTH
PTH, short for parathyroid hormone, is a substance produced by the parathyroid glands, four small glands located behind the thyroid gland in the neck. Its main role is to raise the level of calcium circulating in the blood whenever that level drops below normal.
PTH raises blood calcium through several combined actions, including stimulating the release of calcium stored within bone, increasing the kidneys' reabsorption of calcium so less is lost in urine, and promoting the kidney's activation of vitamin D, which in turn increases calcium absorption from the digestive tract. These combined effects work together to restore normal blood calcium levels.
Blood PTH levels are measured to help evaluate calcium related disorders, and a PTH level that is unexpectedly high or low relative to the blood calcium level can point toward a problem with the parathyroid glands themselves rather than with calcium regulation elsewhere in the body.
Also known as
Used in a sentence
A PTH level was checked after routine blood work showed an elevated calcium level.
Good to know
PTH is interpreted together with the blood calcium level rather than on its own, since a PTH level that does not match what would be expected for a given calcium level is often the clue that points to a parathyroid gland problem.