The thyroid gland is an important organ of the human body and is actively involved in regulating metabolism and circulation. Through the production of the hormones T3 (triiodothyronine) and T4 (thyroxine), doctors can determine whether there is a disorder of the organ based on the thyroid levels present.
Another hormone that plays an important role in assessing thyroid levels is TSH (thyroid stimulating hormone), which is produced in the pituitary gland and regulates the formation of the thyroid hormones T3 and T4. The values determined by a blood test thus not only provide information about the actual activity of the thyroid gland, but also whether the circulation between the brain and the organ is running in a regulated manner.
Elevated or too low thyroid values can be due to a malfunction of the organ and require a detailed further examination. After the blood test to determine the TSH level and the T3 and T4 hormone concentrations has been completed, an ultrasound examination can, if necessary, provide further important information about the type and severity of the disease.
Determining thyroid levels is not only important for adults, but can also prevent possible secondary diseases in children, adolescents and pregnant women.
What is the function of TSH (thyrotropin)?
TSH, as the central thyroid hormone, is produced in the pituitary gland and enters the thyroid gland via the bloodstream, thereby stimulating it to produce the important hormones T3 and T4. If there is a sufficient amount of these hormones in the blood, the TSH level drops to reduce further stimulation of the thyroid gland and prevent overproduction.
Checking the TSH level thus provides initial information about a possible thyroid disease.
Effect of the thyroid hormones T3 and T4
The two peripheral thyroid hormones T3 and T4 perform important functions in the human body and are significantly involved in the control of metabolism. They not only promote the synthesis of proteins in the body’s cells, but are also significantly involved in hormone production in the pancreas and the adrenal gland.
If elevated or low thyroid levels are found in the blood, this is often due to a disease of the organ.
Other important functions of the thyroid hormones T3 and T4:
- Regulation of body temperature
- Regulation of metabolic activity
- Promote the growth of the nervous and bone systems of the unborn child during pregnancy
- Influence blood pressure and heart rate
- Influence cholesterol levels
TSH value – what does it say?
The TSH value, together with the determination of the T3 and T4 hormone concentrations in the blood, provides important information as to whether the thyroid gland is overactive or underactive. If the TSH value is outside the normal range of 0.4 – 2.5 mU/l, the doctor can draw important conclusions about the degree of thyroid disease by taking the T3 and T4 hormone values into account.
It should always be noted that the TSH value changes several times during the day, while it increases slightly in the evening. When a TSH test is carried out, the patient is injected with a dose of TRH so that an exact value can then be determined by means of a blood test.
TSH value too low – what disorders can be present?
If a person has a TSH level that is too low, this can indicate an underactive thyroid gland. In this case, the thyroid gland produces more T4 and T3 and thus inhibits the TSH secretion of the pituitary gland.
- Graves’ disease
- Nodes in the thyroid gland that actively produce hormones
- Enlargement of the thyroid gland (goiter)
TSH value too high – what disorders can be present?
With an increased TSH value, the treating doctor usually assumes a reduced hormone production of the thyroid gland.
- Congenital hypothyroidism
- Hashimoto’s thyroiditis
- Surgical removal Complete or partial removal of the thyroid gland
- Iodine deficiency
If a person has an elevated or low TSH level, in many cases a more accurate diagnosis of the thyroid disorder can be made by comparing the TSH level with the T3 and T4 levels determined by a blood test.
Based on these values, the doctor can get an initial indication of the severity of the disease and initiate appropriate treatment on this basis.
Comparison of the different measured values of TSH, T3 and T4:
Thyroid levels during pregnancy
Pregnancy places high demands on the female thyroid gland, because the need for thyroid hormones increases by about 50 %. A normally functioning thyroid gland can meet this additional demand through sufficient iodine intake.
Since thyroid dysfunction in expectant mothers can lead to miscarriage and physical or mental malformations of the unborn child, it is particularly important to determine thyroid levels during pregnancy.
The normal range of the TSH blood value in pregnant women is 0.1 – 2.5 mU/l and should be routinely checked at the beginning of pregnancy. Not only the TSH value, but also the concentration of the thyroid hormones T3 and T4 should be checked regularly.
Elevated or too low thyroid levels can be due to hypothyroidism or hyperthyroidism and affect the healthy development of the baby.