The normal range values of PTH levels are from 10 to 55 picograms per milliliter, states the National Institutes of Health's MedlinePlus. The PTH test is a blood test used to detect the range values of the parathyroid hormone. The parathyroid glands produce this hormone.
Some reasons a patient may need this test are to detect hyperthyroidism, unexplained osteoporosis and high calcium levels in the blood. When parathyroid levels are either too elevated or low, it can be due to various causes. Abnormally high level of PTH can be an indication of high levels of phosphorus, gland tumors or low levels of calcium in the body. Some causes of low range values of PTH can include excess calcium and sarcoidosis. Damaged parathyroid glands due to either radiation treatments or neck surgery can also lead to abnormally low levels of PTH, notes WebMD.
Humans have four small parathyroid glands that are found in the neck area behind the thyroid glands. Both the thyroid and parathyroid glands are part of the endocrine system.