On the one hand, thyroid hormones are talked about more often in society than any other hormones; on the other hand, not everyone knows when to check their concentrations and what indicators should alert them. We are looking into the issue together with endocrinologist Roman Terushkin.
The thyroid gland is a small butterfly-shaped organ. Despite its small size, this gland performs important functions in the body, and disruption of its functioning quickly affects well-being. For a variety of reasons, thyroid hormones can begin to be produced in too much or too little quantity – both scenarios are not the best for your health.
The role of the thyroid gland in the endocrine system.
“The thyroid gland is, in principle, the conductor of the entire body, the main organ that controls our metabolism, metabolism and condition in general. The disruption of its work does not go unnoticed,” says Roman Terushkin.
Decreased thyroid function leads to weight gain, subsequently to obesity and diabetes. Children experience developmental delays, and adults may experience impaired reproductive function, including the possible development of infertility.
Hypothyroidism during pregnancy is especially dangerous, because thyroid hormones are important for the development of the fetus – their lack can even lead to the child being diagnosed with “cretinism” after birth.
The thyroid gland also affects the cardiovascular system: with a lack of hormones, the heart rate slows down, blood pressure decreases, and hypoxia develops, which is why the brain does not receive enough oxygen. This leads to lethargy, lethargy, apathy, drowsiness, and decreased energy levels.
The opposite situation, if there are too many hormones (hyperthyroidism), also causes a deterioration in the condition, accompanied by symptoms opposite to hypothyroidism. A person loses weight, becomes irritable, his pulse quickens, tremors and excessive sweating appear.
Thyroid hormones and their functions
You can judge about certain diseases by assessing the concentration of thyroid hormones. It is determined using blood tests.
Thyroxine (T4)
T3 and T4 are the main thyroid hormones. They affect the speed of our metabolism and, accordingly, the functioning of all organs. The cells contain the hormone T4 to a greater extent, which gradually turns into the biologically active form of T3.
Triiodothyronine (T3)
Like T4, this hormone is synthesized in the thyroid gland. The activity of T3 is several times higher than the activity of T4.
Calcitonin
A peptide hormone involved in the regulation of phosphorus-calcium metabolism. An analysis to determine the concentration of this hormone is usually done if medullary thyroid cancer is suspected. Calcitonin is a tumor marker; its increase most likely indicates cancer and the need for surgical intervention.
Hormone tests to evaluate the thyroid gland
In order to assess the condition of the thyroid gland, tests are prescribed. Some of them are included in the basic checkup, while others are necessary to clarify the diagnosis if a particular disease is suspected.
- TSH, T3 and T4 free are basic tests that help to understand whether everything is okay with the thyroid gland.
- T3 and T4 general – tests to assess the function of the thyroid gland, showing the content of bound and free forms of hormones in the blood.
· Tests for antibodies to thyroglobulin and antibodies to thyroid peroxidase show whether there are autoantibodies in the body. This is the name given to antibodies against the body’s own cells. Their presence is a sign of autoimmune diseases, in which the body destroys its own thyroid gland.
Thyroid diseases
Some thyroid diseases are common and are accompanied by fairly clear signs, while others are difficult to notice and their diagnosis is not easy.
1. Hypothyroidism
Hypothyroidism is a deficiency of thyroid hormones that can occur when the thyroid gland simply does not receive enough resources to produce the right amount of hormones.
“True hypothyroidism may be preceded by a long stage of subclinical hypothyroidism,” notes Roman Terushkin.
Many people can live with it for years without realizing that excess weight, swelling, drowsiness, fatigue are symptoms indicating that something is wrong with the thyroid gland.
2. Autoimmune thyroiditis
This condition also leads to hypothyroidism. The thyroid gland is destroyed by autoantibodies and simply cannot perform its functions or produce hormones in the required quantities.
“This condition is indicated by an increase in the level of antibodies to TG and TPO, as well as a characteristic picture on ultrasound – the thyroid tissue changes, gaps appear on it, which is why it appears “leaky,” the expert adds [1].
3. Hyperplasia of the thyroid gland
Another common disease in which the thyroid gland, trying to produce more hormones, increases in size and nodules appear on it.
Interpretation of test results in the table
A specialist should decipher test results, but you cannot prescribe therapy for yourself or “treat” tests without consulting a doctor.
Only a specialist will be able to figure out what causes certain deviations from the norm and select the appropriate therapy.
It is important to remember that the tables below present average values; for each laboratory, references may vary slightly.
Normal thyroid hormone levels in women
| Index | Reference values |
| TSH | 0.4–4 mIU/l |
| calcitonin | <5.0 pg/ml |
| T3 general | 0.9–2.5 nmol/l |
| T3 free | 3.1–6.8 pmol/l |
| T4 general | 62–150 nmol/l |
| T4 free | 9–19 pmol/l |
| T4 common during pregnancy |
|
| T4 free during pregnancy |
|
Normal thyroid hormone levels in men
Most indicators for men coincide with normal indicators for women.
| Index | Reference values |
| TSH | 0.4–4 mIU/l |
| calcitonin | <9.2 pg/ml |
| T3 general | 0.9–2.5 nmol/l |
| T3 free | 3.1–6.8 pmol/l |
| T4 general | 62–150 nmol/l |
| T4 free | 9–19 pmol/l |
Normal thyroid hormone levels in children
Thyroid hormone levels in children depend on age.
| Index | Reference values newborns |
Reference values up to 3 years |
| TSH | 0.7–9.8 mIU/l | 0.7–5.9 mIU/l |
| calcitonin | 0–40 pg/ml | 0–15 pg/ml |
| T3 general | 1.2–4.0 nmol/l | 1.5 – 4.0 nmol/l |
| T3 free | 3.0–8.0 pmol/l | 3.0–9.14 pmol/l |
| T4 general | 69.1–206 nmol/l | 77.2–160.9 nmol/l |
| T4 free | 9.8–23.2 pmol/l | 9.0–16.1 pmol/l |
| Index | Reference values 3–8 years |
Reference values 8–14 years |
Reference values 14–17 years |
| TSH | 0.3–5.0 mIU/l | 0.8–3.9 mIU/l | 0.7–2.8 mIU/l |
| calcitonin | corresponds to the norm in adults | corresponds to the norm in adults | corresponds to the norm in adults |
| T3 general | 1.4–3.5 nmol/l | 1.2–3.2 nmol/l | corresponds to the norm in adults |
| T3 free | 4.1–7.9 pmol/l | 3.4–6.8 pmol/l | 3.4–6.8 pmol/l |
| T4 general | 77.2–160.9 nmol/l | 64.3–141.6 nmol/l | 64.3–141.6 nmol/l |
| T4 free | 6.7–16.5 pmol/l | 8.4–13.0 pmol/l | 9.5–15.0 pmol/l |
What does increased or decreased hormone levels indicate?
“There is a negative feedback relationship between the concentrations of thyroid-stimulating hormone and the hormones T3 and T4. TSH is a hormone of the pituitary gland, with the help of which the brain sends a command to the thyroid gland so that it works, explains Roman Terushkin. – If the thyroid gland is healthy and working as it should, the TSH level will be low. If the body feels that there are not enough hormones, then the brain begins to produce TSH in large quantities, “forcing” the thyroid gland to work more intensely. This leads first to subclinical and then to real hypothyroidism.”
If the thyroid gland begins to produce a lot of hormones for some reason, this may indicate the appearance of an active node in it where hormones are produced, or its destruction by autoantibodies.
| Index | Elevated | Reduced |
| TSH | hypothyroidism | hyperthyroidism |
| T3, T4 | hyperthyroidism | hypothyroidism |
| AT-TPO, AT-TG | autoimmune thyroiditis | norm |
How to normalize thyroid hormones
Before starting any therapy, it is important to understand what is the cause of certain problems.
“Finding an active node will most likely lead to surgical removal. Too low a hormone level requires compensation for this level, and when the thyroid gland is destroyed by autoantibodies, the level of these antibodies must be reduced. If this cannot be achieved through therapy, doctors can temporarily prescribe thyreostatics – drugs that suppress the functioning of the thyroid gland,” explains the expert.
How to prepare for a hormone test
No special preparation is required. These tests are taken on an empty stomach, usually in the first half of the day. It makes sense to give up training the day before, remove alcohol and caffeine, and not smoke half an hour to an hour before donating blood.
Thyroid hormone medications (Eutirox, L-thyroxine) may slightly affect test results, therefore, if you are on therapy, you should take the drug after taking blood on the day of donation. But there is no need to cancel it a few days before the test.
Doctor’s recommendations and advice
Roman Terushkin said that it is worth checking the functioning of the thyroid gland once every 6-12 months, even if you feel excellent.
“If you suddenly find that swelling has begun to appear on your face, and this condition lasts for at least a week, if you have started to gain or lose weight, if symptoms have appeared that were not there before, then this is a reason to see a doctor to get tested and checked the functioning of the thyroid gland,” the doctor added.
Questions and answers
The expert not only explained what you need to know about the health of the thyroid gland, but also answered the most common questions about checking this organ.
What is the average price for thyroid hormone tests?
You can get tested either at a clinic at your place of residence – in this case, the tests will be carried out free of charge – or in a commercial laboratory. The price of one test is 500–1150 rubles (excluding blood sampling), a comprehensive examination of the thyroid gland (screening) will cost 3500–5000 rubles.
What foods are good for the thyroid gland?
First of all, foods rich in iodine are beneficial for the thyroid gland – these are seaweed, seafood, and sea fish. However, it is important to understand that in autoimmune thyroiditis, iodine can be harmful [2]. Protein-rich foods are also important for the functioning of the gland. It is from protein that we obtain the amino acid tyrosine, which is necessary for the synthesis of thyroid hormones.
What can be the consequences of removing the thyroid gland?
Removal of the thyroid gland results in the loss of the hormone-producing organ. The only consequence of such an operation is lifelong use of hormonal therapy. There is nothing wrong with this: if the therapy is chosen correctly, and the patient takes it without skipping, then there will be no dangerous consequences.