PTH (parathyroid hormone) is a hormone that is secreted from the four parathyroid glands in the neck, located behind the thyroid gland. It is an important hormone because it helps maintain constant circulating calcium levels.

But why is calcium so important for our body? When is it necessary to evaluate the level of parathyroid hormone in the blood? We spoke with Dr. Andrea Lania, Head of Endocrinology at Humanitas to answer our questions.

Parathyroid gland anatomy in 3d
Parathyroid gland anatomy in 3d

What is a PTH test?

“It is a simple blood test that evaluates the levels of parathyroid hormone, calcium, phosphorus and vitamin D in the blood.”

When and why is a PTH blood test done?

“Performing only a PTH test is in no way sufficient for the diagnosis of disease. In fact, in any clinical condition of a patient, it is vital to associate this test with other tests, in particular to determine the circulating levels of calcium, phosphorus and vitamin D. These series of tests are useful in all those conditions in which there are signs or symptoms that suggest an altered metabolism of calcium, such as for example in post-menopausal women with a framework of osteopenia, osteoporosis or as a result of  an  abutment incidental to altered calcium levels.”

Are there any illnesses associated with this test?

“The examination is typically performed in the presence of important diseases such as primitive hyperparathyroidism, a condition in which high levels of parathyroid hormone are elevated circulating calcium levels. It is also carried out in the case of secondary hyperparathyroidism, a condition in which there is an excessive secretion of parathyroid hormone by the parathyroid glands in response to low blood calcium levels. This condition is linked to or is a deficiency of vitamin D or chronic renal failure. The parameter may be useful even in cases of hypocalcemia, or if you suspect a malfunction of the parathyroid glands, and thus reduced levels of circulating parathyroid hormone, particularly in patients undergoing thyroid surgery.”

Do I repeat the test if the I was screened last year or the test failed?

“First of all, it must be stressed that any test failures (overestimates) do affect the patient’s health, however, it is not enough for diagnosis and therapy, since it must be interpreted in light of the patient’s clinical condition and associated with other clinical and laboratory parameters. Having said this, in order to correctly interpret any type of clinical data, it is important to contact your doctor or health care professional (endocrinologist, rheumatologist, orthopedic or nephrologist) as to whether it is necessary to undergo the test again.”

For more information, you can contact a dedicated number: +39 02 8224 6203.