Calcitonin: Hormone Norm, Blood Test In Women

2024 Author: Rachel Wainwright | [email protected]. Last modified: 2023-12-15 07:39

Calcitonin: hormone norm, functions, deviations

The content of the article:

Calcitonin as a marker
Calcitonin rate
Calcitonin blood test
Conditions in which calcitonin is elevated

Calcitonin (thyrocalcitonin) is a peptide hormone that consists of 32 amino acids and is produced by the parafollicular cells (C cells) of the thyroid gland. It is a functional antagonist of the parathyroid hormone (produced in the parathyroid glands), participates in the regulation of the balance of the activity of osteoblasts and osteoclasts, as well as phosphorus-calcium metabolism in the human body. Until the end, the functions of the hormone calcitonin have not yet been studied.

The hormone calcitonin is produced in the thyroid gland

In the cells of the renal tubules, calcitonin causes an increased clearance and release of ionized calcium, potassium, magnesium, sodium and phosphate. Its effects include a decrease in the content of calcium and phosphate in the blood plasma (increased uptake of calcium and phosphate by osteoblasts), stimulation of the functional activity of osteoblasts, inhibition of the functional activity of osteoclasts and the process of resorption (destruction) of bone tissue.

Calcitonin receptors are found on osteoclasts, in some parts of the brain, in the kidneys. It is metabolized mainly by the kidneys.

An increase in the level of calcium in the blood stimulates the synthesis and secretion of calcitonin, a decrease in the concentration of calcium, respectively, inhibits this process. The secretion of the hormone is stimulated by glucagon and gastrin.

Calcitonin as a marker

Medullary carcinoma, or C-cell carcinoma, can develop from thyroid C cells. This type of malignant tumor is characterized by slow but steady growth. C-cell carcinoma metastases to the lymph nodes of the neck and mediastinum, in addition, with the blood flow, metastases can enter the liver, lungs, brain and bones. Treatment of medullary thyroid cancer presents significant challenges, especially in the advanced and late stages. Surgical removal of the tumor at the initial stage of development is highly effective; in this case, early detection plays a key role. Since medullary cancer grows from cells that secrete calcitonin, its level in the blood rises significantly already in the early stages of the disease. The most reliable early method for detecting medullary thyroid cancer is to determine the concentration of the hormone. The European Thyroid Organization recommends a single blood test for calcitonin in all patients with thyroid nodules.

An increase in calcitonin levels above 100 pg / ml may be a sign of medullary thyroid cancer

The hormone is also a marker of calcium metabolism. In clinical practice, a comprehensive assessment of calcium metabolic disorders in the body is carried out by determining the concentration of calcitonin, parathyroid hormone and vitamin D ₃.

Calcitonin rate

The rate of calcitonin in women differs from that in men, the reference values are presented in the table, however, they may vary in different laboratories depending on the research methods and analyzers used.

Table. Calcitonin blood levels

Floor	Reference values, pg / ml
Male	<18.2
Female	<11.5

When interpreting the analysis results, it should be borne in mind that there is no lower limit of the norm. A decrease in concentration (taken into account during dynamic observation) is observed in the case of physical exertion prior to taking blood.

Content above 100 pg / ml is observed in medullary thyroid cancer, lymphoproliferative diseases, and leukemia. When the level of calcitonin in the blood is more than 100 pg / ml, the probability of confirming medullary thyroid cancer is almost 100%. There is a direct relationship between the degree of increase in the hormone content and the stage of the pathological process (including the presence or absence of distant metastasis). With a neoplasm not exceeding 5 mm in diameter and a calcitonin level less than 40 pg / ml, the presence of regional metastases is unlikely. If the concentration does not exceed 400 pg / ml, the presence of distant metastases is doubtful. Indicators exceeding 400 pg / ml in medullary thyroid cancer, as a rule, indicate the presence of distant metastases.

A slight excess of the norm (that is, indicators are higher than the upper limit of the norm, but less than 100 pg / ml) may indicate both the absence of a neoplasm and a small tumor. Such patients are advised to consult an endocrinologist and additional examination (fine-needle puncture of the node, followed by histological examination of the obtained biological material and determination of calcitonin in the lavage from the needle; a stimulated test, during which the concentration of the hormone in the patient's blood after administration of calcium gluconate, etc.).

Biochemical remission after surgical treatment of medullary carcinoma is considered to be a basal level of calcitonin not higher than 10 pg / ml, which increases by no more than two times upon stimulation with calcium gluconate.

After surgical treatment of medullary thyroid cancer, unfavorable prognostic criteria include the hormone content above 150 pg / ml, as well as a reduction in the time period for a twofold increase in its concentration from two years to six months.

Calcitonin blood test

Determine the content of calcitonin in the venous blood. For analysis after venipuncture, the patient's blood is collected in an empty tube or in a tube with a gel, the sample is cooled (not frozen) and sent to the laboratory. The most reliable method for determining the level of a hormone in the blood is immunochemiluminescent.

1-2 weeks before the blood test for the hormone content, they stop taking medications that can affect the test results. If this is not possible, the direction indicates the drugs that the patient is taking. Distorted research results can be obtained in the case of the use of calcium, glucagon, adrenaline, estrogen, pentagastrin, cholecystokinin, oral contraceptives, etc.

Three days before blood sampling for analysis, physical activity (including sports training) should be excluded, one day - the use of alcoholic beverages, fried and fatty foods, an hour - smoking, for half an hour before taking blood, the patient should be completely at rest. Blood for research must be donated on an empty stomach (it is allowed to drink water), preferably in the morning (at least 12 hours should pass after the last meal).

It is not recommended to take blood immediately after ultrasound examination, fluorography, X-ray examination, rectal examination, as well as physiotherapy procedures.

The analysis is carried out according to the following indications:

identification and differentiation of disorders of calcium metabolism in the body;
diagnostics of neoplasms producing calcitonin,
monitoring the response to treatment of patients with medullary thyroid cancer in order to identify possible recurrence;
screening of family members of a patient with medullary thyroid carcinoma, since 20% of all cases of the disease are familial.

For analysis for calcitonin, blood is taken from a vein

If medullary thyroid cancer is suspected, preoperative examination should include determination of the level of calcitonin, cancer-embryonic antigen, as well as parathyroid hormone, ionized calcium or total calcium and albumin (diagnosis of primary hyperparathyroidism), free normetanephrins and metanephrines in the blood or daily urine (diagnosis of pheochromocytoma). After surgery, the level of calcitonin and cancer-embryonic antigen should be determined no earlier than two to three months.