This test measures the level of parathyroid hormone (PTH) in the blood. PTH, also known as parathormone, is made by your parathyroid glands. These are four pea-sized glands in your neck. PTH controls the level of calcium in the blood.
Too much PTH causes calcium levels in your blood to rise too high, which can lead to health problems such as bone thinning and kidney stones. Doctors usually catch primary hyperparathyroidism early through routine blood tests, before serious problems occur