La parathormone, PTH or even parathyroid hormones is a hormone secreted by parathyroid glands. It plays a major role in regulating the distribution of calcium the body. Its main role is to stimulate the release of calcium from the bones and the reabsorption of calcium from the kidneys to increase the blood calcium level.

Thus, the parathyroid hormone has an effect ” hyper-calcemic “And” hypo-phosphorémiant »(It lowers the level of phosphates at the same time).   

In the blood, we find the hormone intact (PTH 1-84) but also fragments which complicate the dosage.

The dosage of parathyroid hormone is recommended in the following cases:

• byhypercalcemia (too much calcium in the blood)
• anomaliesphosphocalcic balance
• de kidney stones (renal lithiasis)
• for the follow-up of people withrenal failure and dialysis
• to guide the diagnosis in case of deficiency in vitamin D.

The dosage may also be recommended in postmenopausal women withosteoporosis.

It is always carried out at the same time as a “phosphocalcic” assessment, namely a measurement of the levels of calcium and blood phosphates.

Le dosage is done from a venous blood sample. No preparation is necessary. Your doctor may ask you to stop taking certain medicines before the test, which may influence the results.

Several types of measurements are used and the results may vary from one laboratory to another. In general, the concentration of PTH in the blood varies between 6 and 50 pg / ml (picograms per milliliter).

Its rate may be too high or too low. The doctor, by combining this dosage with the phosphocalcic balance, will be able to guide his diagnosis.

Thus, in the event of an excessively high PTH level associated with hypercalcemia, it is likely that the diagnosis ofhyperparathyroïdie is posed. The causes are multiple (including certain cancers).

In case of high PTH level andhypocalcemia, it may be secondary hyperparathyroidism. The main causes are vitamin D deficiency and kidney failure.

On the contrary, in the event of decreased PTH, hypocalcemia and hyperphosphatemia, it is probably a question ofhypoparathyroïdie. This can be secondary to an ablation of the thyroid, but also to pathologies such as hemochromatosis or inflammatory or infectious conditions.