The blood test for thyroid hormones can be prescribed by doctors of different specializations and is currently the most often recommended of all hormone tests. This study is relevant for the female half of the population, in which thyroid diseases occur ten times more often than men. Let's consider more in detail, for what hormones TTG and T4 are responsible, what their normal values, and that can designate deviations.
Thyroid hormone production
The thyroid gland is the organ of the endocrine system, which plays a key role in the regulation of most essential processes in the human body. It consists of a connective tissue that is pierced by nerves, blood and lymph vessels. Shchitovidka contains special cells - thyreocytes, which produce thyroid hormones. The main hormones of the thyroid gland are T3 (triiodothyronine) and T4 (tetraiodothyronine), they contain iodine and are synthesized in various concentrations.
Synthesis of thyroid hormones is due to the development of another hormone - TSH (thyrotropin). TTG is produced by the cells of the hypothalamus when it receives a signal, thereby stimulating the activity of the thyroid gland and increasing the production of thyroid hormones. Such complicated mechanisms are required in order that the blood is stably present as many active thyroid hormones, as required for the body at one time or another.
Norms of thyroid hormones TTG and T4 (free, general)
The level of a hormone TTG can tell a specialist about the general condition of the thyroid gland. The norm is 0.4-4.0 mU / L, but it should be noted that in some laboratories, depending on the test method used, the normal limits can vary. If the TSH is higher than the limit value, it means that the body lacks thyroid-stimulating hormones (TTG reacts to this in the first place). At the same time, changes in TSH can depend not only on the functioning of the thyroid gland, but also on the functioning of the brain.
In healthy people, the concentration of thyroid-stimulating hormone changes within 24 hours, and the greatest amount in the blood can be detected in the early morning. If TTG is higher than normal, it could mean:
- serious mental illness;
- problems in the functioning of the adrenal gland;
- excessive physical exertion;
- pregnancy;
- hypothyroidism;
- absence of gallbladder;
- severe gestosis, etc.
Insufficient amount of TSH may indicate:
- thyrotoxicosis;
- decreased function of the pituitary gland;
- brain tumors;
- benign education in the thyroid gland, etc.
The thyroid hormone T4 in women is:
- free (not associated with blood proteins) 0.8-1.9 ng / dl;
- total 4.5-12.5 μg / dl.
The T4 level remains relatively constant throughout life. The maximum concentrations are observed in the morning and in the autumn-winter period. The amount of total T4 increases with the bearing of the child (especially in the third trimester), while the content of the free hormone may be reduced.
The pathological causes of an increase in the hormone T4 can be:
- obesity;
- toxic goiter ;
- inflammatory processes in thyroid tissue;
- HIV infection;
- malignant tumor of the uterus, etc.
Reducing the amount of thyroid hormone T4 is often indicative of such pathologies:
- deficiency of iodine in the body;
- autoimmune thyroiditis ;
- disruption of the hypothalamus;
- neoplasms in the thyroid gland, etc.