Indications of thyroid hormones. Thyroid hormone tests: norms and interpretation

How to properly take ✅ blood tests if your thyroid is bothering you? This article will answer basic questions from patients.

The doctor ordered a blood test to diagnose the thyroid gland. But not every doctor explains how to do this correctly. And the patient may have the most unexpected questions about the procedure for donating blood “for thyroid hormones.” Therefore, let's consider typical rules for such analysis.

How to get tested for thyroid hormones

1. List of blood parameters that should be ordered from the laboratory

The minimum set is three indicators:

1. TSH (thyroid stimulating hormone),
2. T4-free (thyroxine),
3. T3-free (triiodothyronine).

It is a mistake to determine only TSH, or TSH and T4-free, or TSH with common T4 and T3.

If you are performing a blood test for the first time, it is better to evaluate all the main indicators: TSH, T3w, T4w, T4tot, T3tot, AT-TPO, AT-TG.

If you know about the presence of a node(s) in the thyroid gland, then order calcitonin assessment. For thyrotoxicosis - AT-rTSH.

Recent scientific studies have confirmed the mandatory assessment of all three blood parameters.

A story from life. It happened twice that I donated blood in laboratories myself. For some reason, young women immediately appeared behind me, filling out documents with the laboratory administrator for a TSH and T4F blood test.

I tried to suggest. He introduced himself as a thyroidologist (for the thyroid gland) and reported that it was necessary to determine, along with TSH and T4free, T3-free - the main hormone of the thyroid gland (so he told them). But they only smiled sweetly, as if they had been given a compliment. Nothing in their order was changed.

2. When is the best time to donate blood for testing?

Traditionally, this is suggested to be done in the morning on an empty stomach. But in the case of thyroid hormones and TSH, you can donate blood to the laboratory any time of the day.

Of course, there are daily fluctuations in TSH and thyroid hormones, but they have little effect on the values ​​of hormonal parameters and antibodies.

Is it better to donate blood at the same time? Yes, but not necessarily.

3. Do I need to stop taking the drug before donating blood for analysis?

For hypothyroidism, patients take hormonal medications and/or potassium iodide. For hyperthyroidism - thyreostatics. In these two cases there is no need to worry.

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The fact is that the drugs act mainly cumulatively. That's why, If you forgot to take your medication one day, you should not take a double dose the next day!

Also, you should not continue to give up hormonal or thyreostatic drugs (Eutirox, L-thyroxine, Tyrosol, Propicil, etc.) for a long period (1-4 months) to obtain real data. A competent doctor will be able to guide you to a certain extent if you indicate the dose you are taking and the duration of use.

Advice. Mark the dose and name of the drug on the blood test form, as well as the period for taking this particular dose. Save your blood test forms.

So, There is no need to stop taking the drug before donating blood.

4. Does the reliability of a blood test for thyroid hormones and TSH depend on the day of the menstrual cycle?

Usually, there are no significant effects of the period of the menstrual cycle on the reliability of the assessment of thyroid blood parameters. You can donate blood on any day of your cycle. But better - between menstrual days.

5. Does taking antibiotics, vitamins, NSAIDs and contraceptives affect the result of a blood test “for thyroid hormones”?

Many medications have almost no effect on the results of blood tests for thyroid hormones and TSH. But there are means that can “distort” the picture a little. In addition to the hormones of the thyroid gland itself and thyreostatics, medications containing iodine can have an effect. Such drugs, for example, include cordarone (amiodarone). published

The materials are for informational purposes only. Remember, self-medication is life-threatening; be sure to consult a doctor for advice.

P.S. And remember, just by changing your consumption, we are changing the world together! © econet

Hormonal disorders of the thyroid gland are a sign of the development of serious pathologies in the body. According to statistics, such disruptions in the endocrine system occupy second place in the world after diabetes mellitus. Therefore, it is important to regularly visit an endocrinologist to monitor hormone levels and timely diagnosis of thyroid pathologies.

COST OF SOME ENDOCRINOLOGIST SERVICES IN OUR CLINIC IN ST. PETERSBURG

What hormones does the thyroid gland produce and why are they needed?

The thyroid gland is one of the most important organs of the endocrine system. This butterfly-shaped gland is located on the front of the neck, just below Adam's apple. It has two petals connected by a thin isthmus and, in response to the pituitary thyroid-stimulating hormone, produce their own hormones that perform the regulatory and coordinating function of human organs.

Thyroid hormones, called iodine-containing peptides, are triiodothyronine (T3) and thyroxine (T4). These hormones play an important role in human life and have a decisive influence on metabolism (metabolism), growth and development of the body of any person.

T3 and T4 are produced by the follicular cells of the thyroid gland in response to the pituitary hormone TSH. Their production requires two main components - iodine and the amino acid tyrosine, which usually enter the body with food and water, so it is important that they are present in sufficient quantities in the diet.

When synthesizing hormones, the thyroid cell (thyrocyte) produces a glycoprotein substance (thyroglobulin), which accumulates in the cavity of the thyroid follicle and serves as a kind of “reserve” for the rapid synthesis of hormones.

In addition to the hormones T3 and T4, the thyroid gland produces, along with C cells, another hormone known as calcitonin, which is involved in the regulation of calcium and phosphorus metabolism and bone development.

• The production of thyroid hormones is regulated by a mechanism that reduces the rate of production when circulating hormone concentrations are high, and increases it when the concentration of hormones in the blood decreases.
• Regulation is carried out by the hypothalamic-pituitary system through a negative feedback mechanism.

The pituitary gland synthesizes thyroid-stimulating hormone, which enhances the synthesis and release of T3 and T4 into the blood. The secretion of TSH, in turn, is regulated by the function of the hypothalamus, which produces thyrotropin-releasing hormone. In this way, a hormonal balance is maintained that is adequate to the body's needs.

The importance of thyroid hormones

Thyroid hormones play a fundamental role in the proper functioning of metabolism, growth and development:

• Metabolism.Thyroid hormones increase both basal metabolism and metabolic activity of all tissues. Basal metabolism refers to the energy expenditure of a person at rest and wakefulness. For example, a person with elevated thyroid hormone levels will have increased energy intake. Thyroid hormones also affect glucose and lipid metabolism, increase protein synthesis, increase cardiac contractility, and increase heart rate. Thus, with hyperthyroidism, one of the main symptoms is tachycardia.
• Height. Thyroid hormones are essential for normal human growth, as evidenced by slow growth in cases of hormone deficiency.
• Development.A classic experiment in endocrinology was the demonstration that tadpoles deprived of thyroid hormones could not be transformed into frogs. This reinforces the fact that normal hormone levels play a fundamental role in fetal and newborn brain development.

Additional influence of hormones

Thyroid hormones have a profound effect on almost the entire body:

central nervous system. A sufficient level of thyroid hormones in the last phase of development of the fetus and newborn is an important condition for the normal development of the central nervous system. Hormonal imbalance of the thyroid gland during this delicate period leads to cretinism or irreversible mental retardation. Early diagnosis and adequate replacement therapy in the third week of life can prevent serious and undeniable consequences.

In an adult, both a decrease and an increase in the concentration of thyroid hormones lead to changes in mental state. A decrease in thyroid hormone levels causes a person to feel lethargic, while an excess of hormones provokes anxiety and nervousness.

Sympathetic nervous system. Thyroid hormones increase the number of specific receptors with which catecholamines (chemicals such as adrenaline that transmit nerve impulses at the level of sympathetic nerve endings) interact. It occurs mainly in the heart, skeletal muscle, adipose tissue and lymphocytes.

The cardiovascular system. Thyroid hormones increase myocardial contractility, heart rate, and venous return to the heart, significantly improving cardiac function. They also promote vasodilation, which leads to increased blood flow to many organs.

Respiratory system. Thyroid hormones influence the response of nerve centers to respiratory stimuli. In practice, they perform an irreplaceable function - an effective response of the lungs (variation of the frequency and amplitude of respiratory movements) to various factors (for example, oxygen deficiency). This also explains the hyperventilation and functional impairment of the respiratory muscles that occurs with hypothyroidism.

Skeletal apparatus. The thyroid gland is fundamental to skeletal development and formation: insufficient production of thyroid hormones during fetal development and childhood causes stunted bone growth, which can lead to dwarfism. Hormone replacement therapy will ensure normal skeletal development, but only if the problem is diagnosed and treated before puberty.

Digestive system.The movement of the smooth muscles of the stomach and intestines is facilitated by thyroid hormones, so in conditions of hyperthyroidism diarrhea is observed, and in situations of hormonal deficiency (hypothyroidism) constipation can occur. In the latter case, the activity of the digestive system as a whole decreases, and the metabolism slows down with subsequent weight gain.

Reproductive system. Excess or deficiency of thyroid hormones can cause infertility and reproductive problems, especially in women. In women suffering from hypothyroidism, there is an increase in the production of prolactin (a hormone secreted by the pituitary gland). This can cause menstrual irregularities or even amenorrhea (complete absence of periods). In men, thyroid dysfunction can cause erection problems and, in extremely rare cases, infertility.

Apparatus for hematopoiesis.Thyroid hormones influence the production of red blood cells (erythropoiesis), which originate in the bone marrow. In the case of hypothyroidism, anemia often occurs, while in the presence of increased hormonal activity, the production of red blood cells is stimulated due to increased oxygen demand in the tissues.

Hormonal imbalances

There are several diseases associated with the level of thyroid hormones:

• hyperthyroidism – increased levels of hormones. They affect biochemical processes in the body;
• Hypothyroidism is a condition caused by an underactive thyroid gland. The gland is unable to synthesize the amount of hormones T3 and T4 adequate to the needs of the body, and this determines a decrease in all metabolic processes;
• a disease associated with anatomical changes in the thyroid gland, in which the level of hormones is normal.

Hypothyroidism

Deficiency of thyroid hormones causes the following symptoms, which are the reason for an urgent visit to an endocrinologist:

• Depression and fatigue, especially when waking up and resting, loss of memory, concentration and learning ability, drowsiness, apathy, disinterest, decreased speed of thought and speech, alternating with nervousness and hyperactivity;
• Dry and pale skin, hair loss and dryness, thinning of the outer eyebrows, brittle nails with grooves, constipation, poor digestion, low body temperature, poor sweating in the heat;
• High risk of infection, weakened immune defense and predisposition to cancer;
• Decreased insulin sensitivity, metabolic syndrome, slow heartbeat, increased cholesterol and diastolic pressure, atherosclerosis, increased risk of death from heart disease (heart failure, coronary artery disease, arrhythmias);
• Night muscle cramps, myalgia, pain and stiffness (especially in the morning), headache, menstrual irregularities, uterine bleeding, infertility, tendency to terminate pregnancy, decreased tendon reflexes, enlarged thyroid gland (endemic goiter).

Reduced thyroid function will have consequences in many other hormonal areas. In particular, hypothyroidism creates a stressful situation that stimulates the adrenal glands, contributing to its development towards decompensation. “Adrenal fatigue” and hypothyroidism are often related (in 80% of cases) and aggravate each other.

The most common causes of hypothyroidism are autoimmune diseases (Hashimoto's thyroiditis), iodine deficiency, and problems with the hypothalamus and pituitary gland (the rarest hypothesis).

Hypothyroidism is an irreversible pathology. This means that the thyroid gland cannot resume its regular functioning. For this reason, the therapy taken is defined as “replacement”, in the sense that it is intended to replace hormones that the thyroid gland can no longer produce.

Hyperthyroidism

An overactive thyroid gland causes predominantly opposite symptoms:

• endemic goiter - the thyroid gland has increased in size;
• hair began to fall out rapidly and nails began to break;
• bulging eyes appeared;
• sudden outbursts of aggression, nervousness, anxiety;
• irritability gives way to tearfulness;
• tremors in the hands;
• increased sweating;
• rapid weight loss;
• causeless fatigue and weakness, insomnia;
• increased body temperature (at low temperatures a person is not cold);
• increased heart rate (tachycardia);
• suffers from diarrhea;
• dystrophic changes in the liver (with a long course of the disease);
• in severe cases, women experience uterine bleeding, and men experience changes in the testicles and prostate gland, decreased libido.

One of the most common causes of the disease is Graves' disease, an autoimmune disease that causes the body to produce autoantibodies that activate the secretion of thyroid hormones. Also, overactivity of the gland can be caused by Hashimoto's thyroiditis, toxic, taking certain medications or supplements with a high iodine content, etc.

Hyperthyroidism can usually be diagnosed and treated in a clinic without the need for hospitalization. Various types of treatment are possible: pharmacological, surgical, with radioactive iodine and, in the case of toxic adenoma, by alcoholization. The doctor prescribes the most appropriate therapy depending on the specific pathology.

Hormone analysis

A blood test for thyroid hormones is necessary if the above symptoms are present. Blood is taken from the ulnar vein on an empty stomach in the morning. Before this, you need to be at rest for half an hour.

Preparation for analysis implies compliance with the following rules:

• stop smoking, drinking alcohol and psychostimulants (caffeine) one day before;
• for 2-3 days, exclude fried, hot, spicy and other heavy foods from the diet;
• avoid physical and emotional stress for 12 hours;
• stop taking medications that affect the level of thyroid hormones one month before;
• 3-4 days in advance, exclude iodine-containing foods (seaweed, fish, iodized salt) from the diet.

A complete and detailed biochemical study includes assessment of the following indicators:

The normal level of hormones is largely determined by the intensity of physical activity, emotional state and time of year. For certain categories of people, hormone levels may also differ.

These include:

• people over 50 years old;
• teenagers;
• children under 12 years of age;
• children of “turning-point” age;
• pregnant women.

The doctor may prescribe the determination of only some of these indicators. So, for the treatment of the thyroid gland, it is enough to determine only two indicators - free T4 and TSH. During pregnancy, 4 indicators are determined - TSH, free T3, free T4 and AT-TPO. Due to the laboriousness and high cost of the procedure for determining each indicator, it is recommended to study only those indicators, changes in which may be the cause of the corresponding symptoms.

What does a change in hormone levels indicate?

Based on the results of the analysis, the endocrinologist determines the diagnosis or condition of the body.

Additional indicators:

• TG. An increased level of the hormone is a sign of non-toxic, endemic, multinodular or diffuse goiter, thyroid cancer, thyroiditis;
• AT-TPO. Exceeding the norm indicates the development of a malignant tumor;
• Calcitonin. It is one of the basic tumor markers and indicates the presence of a malignant process.
• AT-TG. An excess of the normal value may indicate Graves' disease, thyroiditis, idiopathic myxedema, pernicious anemia, thyroid carcinoma (cancer) or other autoimmune and chromosomal pathologies.

Prevention

In order to prevent thyroid diseases associated with hormonal imbalance, or eliminate minor disruptions, it is necessary to ensure that the body receives a sufficient amount of tyrosine and iodine from food.

The main iodine-containing products are sunflower oil, iodized salt, kelp seaweed, crabs, fish (oceanic), shrimp, squid, etc. Tyrosine is found in eggs, milk, peanuts, peas, and beans. Maintaining hormonal balance is the key to a healthy thyroid gland. And all you need for this is a complete and balanced diet. Also, do not forget about regular visits to the endocrinologist. Checking once every 3 months is sufficient.

Thyroid hormones
The thyroid gland in the human body is the most important secretory organ and is responsible for the production of hormones that control the normal functioning of the body.
Thyroxine and triiodothyronine, the main hormones of the thyroid gland, are responsible for metabolism, the growth of tissues and organs, the condition of bone tissue and the calcium content in it. Calcitonin is a thyroid hormone produced by cells of neuroendocrine origin located among the follicles, a tumor marker; determining the level of calcitonin makes it possible to diagnose medullary cancer even in the early stages.
Pathological changes in the functioning of the thyroid gland can lead to an excess or deficiency of hormonal substances, which, in turn, has a detrimental effect on a person’s health and well-being.
When is thyroid hormone testing prescribed?
The main signs indicating a malfunction of the organ are:
overweight;
lack of body weight;
excessive sweating;
arrhythmia;
menstrual cycle disorders in women;
increased fatigue;
mood swings, psychosis;
blood pressure surges;
absent-mindedness, inability to concentrate.
A referral to donate blood for thyroid hormones is usually given by a general practitioner, endocrinologist or gynecologist.
Attention! Women during pregnancy and after the age of 50 are especially susceptible to thyroid diseases; they are at risk. It is recommended to have a blood test annually to monitor hormone levels.
Common thyroid diseases
Let's consider the two most common problems caused by malfunctions of the organ and causing maximum inconvenience to patients: hyperthyroidism and hypothyroidism.
Hyperthyroidism is the overproduction of hormonal substances. The disease is dangerous due to its complications:
arrhythmia and other problems with blood vessels and heart;
pathological conditions of internal organs;
reduced amount of calcium in bone tissue, which can lead to fractures and other serious injuries;
inflammation of the soft tissues around the eye sockets, which can lead to vision loss.
Hypothyroidism is the insufficient production of hormones by the thyroid gland. An illness left without proper treatment can cause the following complications:
enlargement of the thyroid gland;
swelling of the limbs and face;
disruption of the normal functioning of the gastrointestinal tract;
mental disorders up to psychosis and depression;
diabetes;
ovarian dysfunction, which can ultimately lead to female infertility;
Metabolic coma is a dangerous complication that can lead to death.
Rules for taking the analysis
It is necessary to prepare for donating blood for analysis to determine the level of thyroid hormones for at least 7 days. This will ensure the reliability of the information received and will allow your attending physician to accurately diagnose, determine which organs and systems are susceptible to harmful effects, and how to correct it.
Preparation rules to obtain reliable results:
1. Stop smoking 1 hour before visiting the laboratory.
2. Do not take medications 2 days before the test.
3. Quit hormonal medications one day before.
4. Do not expose your body to excessive physical activity. do not visit saunas, solariums, baths two days before the test.
5. Follow a special diet for a week: exclude alcohol-containing drinks, fatty, smoked, spicy, salty and fried foods.
It is worth noting that there is no difference in preparation for donating blood between female and male sexes, since the phase of the menstrual cycle does not in any way affect the amount of hormones in the blood.
You can donate blood for thyroid hormone testing in Moscow at a reasonable price at one of the Mobilemed medical centers. The test is taken on an empty stomach in the morning.

Blood testing for thyroid hormones is one of the mandatory tests when there is a suspicion of diseases of the endocrine system. The specialist will give directions and explain the rules for taking the test.

This analysis will show the presence or absence of thyroid disease. The study will provide sufficient information for specialists to begin prevention or treatment of a patient seeking help.

All hormones play an important role in the life support of human body systems. But there is a system that produces them, saturating cells and tissues.

Two compounds are synthesized by the gland:

1. Triiodothyronine T3.
2. Thyroxine T4.

A special type is produced by an organ of the endocrine system - the pituitary gland. This is thyroid stimulating hormone (TSH).

TPO is an enzyme that synthesizes T3, T4.

1. Free T3 is responsible for stimulating the production of microelements and saturating the cells of internal organs with oxygen. It also controls the exchange of oxygen between different systems.
2. Free T4 stimulates and controls the metabolism of protein formations. Using T4, the presence and development of thyroid diseases are detected: thyroiditis, toxic goiter, hypothyroidism.
3. TSH is involved in the creation and synthesis of T3 and 4. Diagnosis of the quantitative composition allows us to identify hypo- and hyperthyroidism of the gland.
4. Concentration of AT (antibodies) to thyroglobulin. The compliance standard will show the amount of building blocks T3, T4 and TSH protein to antibodies. Detection of antibodies in the patient’s blood will be evidence of damage to the autoimmune system. Diseases of glandula thyroidea - diffuse goiter, a type of Hashimoto's pathology.
5. The concentration of AT (antibodies) to the enzyme produced by the thyroid gland, thyroid peroxidase. Pathological deviations of the autoimmune system appear against the background of a violation of the normal ratio.

The thyroid gland produces hormones to ensure the stability of all systems of the human body. The gland is responsible for energy metabolism and the activity of the autonomic nervous system.

Many doctors try to explain the tasks of the thyroid gland by comparing the human body to a boiler room that provides heat to an entire city. Thyroid hormones supply the entire body with heat, being responsible for its normalization. Any deviation from the desired temperature leads to breakdown. It gets hot or cold. Under normal conditions, the functioning of the thyroid gland remains invisible. Any failure becomes the cause of all troubles.

Ensuring vital activity and proper functioning of all body systems depends on a normal background. There must be a set amount of hormones in the blood. To determine whether they meet the norm, laboratory blood tests are performed. Experts consider radioimmunoassays to be the most commonly used method. The method is complicated by the need to use radioactive isotopes.

Most laboratories perform other tests:

• immunoenzyme;

Glandula thyroidea produces hormonal compounds.

Their rate depends on external factors and the condition of the gland:

• The intensity and activity of signals coming from the brain affect the thyroid gland. The rate of substances necessary for the endocrine system to function directly depends on the intensity.
• The number of cellular formations of the thyroid gland. Not all gland cells are functional, so not all produce the necessary substances. The rate of production depends on the efficiency of the cells.
• Iodine. The synthesis of TSH depends on the quantitative norm of iodine microelements in the thyroid gland. Any deviation of iodine from the norm leads to pathological damage.

Normal ratio and amount of hormones (minimum/maximum)

1. Free T3. Minimum – 2.6 pmol/l. Maximum – 5.7 pmol/l.
2. Total T3. Minimum – 1.2 nmol/l. Maximum – 2.2 nmol/l.
3. Free T4. Minimum – 9.0 pmol/l. Maximum – 22 pmol/l.
4. General T4. Minimum – 54 nmol/l. Maximum – 156 nmol/l.
5. TSH. Minimum – 0.4 honey/l. Maximum – 4 mU/l
6. Calcitonin. Minimum 5.5 nmol/l. Maximum – 28 nmol/l.

A specialist can decipher the results. He will take into account not only the deviation from the norm, but will take into account the gender and age of the patient. Simply the numbers in the table will not be able to provide the necessary information. The endocrinologist will choose the method of taking tests.

A blood test for thyroid hormones will show the condition of glandula thyroidea. A decrease in its work in medical practice is called hypothyroidism. Iodine deficiency disrupts the body's normal production of microelements and results in disease. Among other common reasons for deviations from the required amount, a special place is taken by the use of certain medications and medications.

Deficiency is caused by removal of the thyroid gland, tumor formations, and lack of TSH production:

1. Primary hypothyroidism. Free T3, T4 are normal or slightly reduced. TSH level is elevated.
2. Secondary hypothyroidism. Free T3, T4 are reduced. TSH – high.
3. Hyperthyroidism. Free T3 and T4 are in increased quantities. TSH – reduced amount.

Hypothyroidism is dangerous for children.

It leads to various manifestations of abnormal development:

• delayed physical growth;
• cretinism;
• disproportion of body parts;
• deviations in mental state.

The thyroid gland is responsible for many processes in the body. The vital activity of important systems depends on its performance. The thyroid gland, in turn, depends on the amount of substances entering it. Insufficient amounts of microelements lead to dysfunction.

Symptoms of pathological manifestations are as follows:

• increased weight gain, not confirmed by changes in diet or physical activity;
• lethargy, drowsiness and fatigue;
• feeling of tension, depression;
• disturbance in the course of monthly cycles;
• dysfunctional reproductive functions;
• low body temperature;
• skin lesions: dryness, itching, swelling;
• Dandruff;
• deterioration of nail condition;
• worsening bowel movements: constipation;
• swelling of the legs, face;
• feeling of cold regardless of the ambient temperature;
• pain in muscles and joints;
• slowing down of memory properties.

Medical practice describes cases opposite to hypothyroidism. The thyroid gland begins to work at an increased speed, a change occurs in the volume of the organ itself, the amount of T3, T4 becomes excessive, unnecessary for normal functioning. Signs of the disease are enlarged eyes and exophthalmos.

The increased background is characterized by the following changes:

1. Increased appetite due to weight loss.
2. General fatigue of the body.
3. Unreasonable agitation and irritability.
4. Reproductive dysfunction leading to infertility.
5. Disruptions in women's menstrual cycles.
6. Rapid aging of the skin (flabbiness).
7. Increased body temperature.
8. Increased blood pressure.
9. Increased heart rate.
10. Internal burning sensation, heat.
11. Deterioration in the quality of mental activity: memorization.

It is not possible to come to the laboratory and conduct a blood test on any day when the patient feels a deterioration in health and will connect them with the gland. It may take a month from appointment to examination. The body needs to be prepared. The specialist requires accurate objective data. To obtain them, certain preparation of the patient is required.

The set of preparatory measures is as follows:

1. Stop taking medications containing hormones and iodine.
2. Prepare to take a break from eating. Approximately 12 hours should pass between taking the test and eating. The delivery time accepted by doctors is from 8 to 10 o’clock.
3. The human body must be in a state of normal body temperature: you cannot overheat or overcool.
4. Emotional calm of the patient.
5. Avoid alcohol and smoking 7 days before the examination.
6. Avoid physical activity;
7. Stop using medications that affect the thyroid gland. This should be done after consulting a specialist.

Before taking the tests, fill out a referral form. It indicates what medications the patient was taking before the laboratory procedure. All instructions from the endocrinologist must be followed exactly, rules and recommendations must be followed.

The concentration of antibodies against thyroid peroxidase is checked only once. The disease does not respond to changes in the ratio.

The dynamics of pathology follows its own laws:

1. The study of the amount of free and bound TG cannot be carried out in 1 analysis. A comprehensive analysis of these data is not carried out. Each category requires separate verification.
2. If the thyroid gland has not undergone surgery, thyroglobulin tests are not needed.
3. TG protein is tested after surgery to remove the thyroid gland. It provides information about the presence of relapse. The protein norm, even in an absolutely healthy person, can be elevated. The protein will provide the necessary information to the specialist after surgery.
4. The concentration of antibodies to thyroid-stimulating hormone is checked on the recommendation of a doctor in case of thyrotoxicosis, organ hyperfunction. If there is no suspicion of the development of hyperthyroidism, the analysis is not performed.
5. Calcitonin is tested 1 time. It is pointless to do several repeated studies.

All standards are recorded in international medical documents. But the indicators depend on the equipment and methods (reagents used).

The thyroid gland and its hormones are involved in the functioning of all organs and systems of the human body. Any disruption in its functioning can lead to serious health problems. Analysis of thyroid hormones is one of the ways to monitor its functioning and diagnose possible pathological changes.

Hormones and their role

The main hormones that are studied:

• Triiodothyronine (T3),
• Tetraiodothyronine (T4). It is also called thyroxine,
• Thyroid-stimulating hormone (TSH),

The thyroid gland produces 3 substances:

• Calcitonin.

Hormones include triiodothyronine and thyroxine. They help to function as an internal organ of the human body. They contain iodine molecules: 3 in triiodothyronine and 4 in thyroxine.

Calcitonin is produced by C cells. Their functional purpose is calcium metabolism and the development of the skeletal system.

Hormones circulate in the blood in free form and bound to proteins. 99% is bound, only 0.2-0.5% is free.

The hormone T3 is considered more active. It is involved in all biological effects. T4 is the source of the formation of this active substance.

Thyroid hormones are primarily responsible for energy metabolism. This process occurs constantly in the body, even at rest.

Tests of the thyroid gland for hormones involve the determination of TSH (thyroid-stimulating hormone), although it is produced by another endocrine organ - the pituitary gland. It is produced when there is insufficient secretion of T3 and T4. TSH by feedback mechanism. Then there are 2 scenarios for the development of events:

• The gland will synthesize hormones more intensively,
• The thyroid gland is “destroyed.” She gradually increases the volume.

The AT TPO indicator will appear on the blood test results form.

Antibodies to thyroid peroxidase are an indicator of the aggression of the immune system towards its own body. Thyroid peroxidase provides the formation of an active form of iodine, which can be included in the process of iodification of thyroglobulin. Antibodies to the enzyme block its activity, as a result of which the secretion of thyroid hormones decreases. However, TPO Abs can only be “witnesses” of the autoimmune process. An increase in the titer of antibodies to peroxidase is possible if the patient:

• diffuse toxic goiter,
• nodular goiter,
• subacute de Crevin's thyroiditis,
• postpartum gland dysfunction,
• thyroiditis (Hashimoto's),
• idiopathic hypothyroidism,
• autoimmune thyroiditis,
• non-thyroid autoimmune diseases.

When is the test prescribed?

Today, diseases associated with improper functioning of the thyroid gland are the second most common, followed by diabetes mellitus. The condition of the heart, vascular, reproductive and hematopoietic systems depends on the proper functioning of this organ.

A blood test for thyroid hormones can also be performed on the patient’s own initiative. Popular reasons for this decision are:

• Checking the health status of a married couple who decided to have a child,
• By virtue of the profession. If a person works in a place with an increased risk of chemical or radiation contamination,
• Checking the condition of the gland after a previous illness.

The endocrinologist writes a referral for blood tests for thyroid hormones in order to identify abnormalities or adjust the course of treatment for existing diseases.

The reasons for such an appointment may be:

• Sudden changes in a person's weight
• Difficulty conceiving a child,
• Difficult pregnancy
• Menstrual cycle disorders in women,
• Delayed physical or mental development of the child.

If a visual examination reveals structural changes in the gland, a hormone test is also prescribed. Such changes may be nodularity, heterogeneity, or increases in size detected upon palpation of the corresponding area. If there are deviations in the results, the patient will have to undergo additional examinations to identify the cause of the disorder.

You need to donate blood for thyroid hormones if you have the following visual symptoms:

• Tremors are rapid and rhythmic spontaneous movements of the limbs associated with muscle contractions,
• Baldness,
• Heavy sweating
• Memory impairment
• Skin problems
• Tachycardia.

In some cases, tests for thyroid hormones are the norm. Patients suffering from connective tissue pathologies (rheumatoid arthritis, systemic scleroderma, lupus erythematosus) should not forget to donate blood for thyroid hormones.

Standards for adults

T4 remains unchanged in most cases. It is stable even in the presence of a benign tumor or colloidal goiter in the body. With normal thyroxine levels in the female body, the numbers on the results form should be 9-19 pmol/l. This indicator is the iodine basis for the formation of the T3 hormone. A woman’s levels of this hormone should be in the range of 2.62-5.69 pmol/l. The level of thyroid hormones in women during pregnancy is much higher. This is due to the fact that, up to a certain point, the mother’s endocrine system works for two, thereby satisfying the needs of the baby too. Thyroid hormones: normal in women, table below.

Naturally, the doctor will decipher the answers received. You can only slightly compare the numbers with the standards.

Thyroid-stimulating hormone at normal concentration should be 0.2-3.2 Mme/l. Exceeding the indicator indicates insufficient functioning of the thyroid gland, low levels indicate too intense secretion.

A breakdown of the blood test for thyroid hormones and a comparison of the indicators of men and women is given in the table below.

Norms for children

Thyroid hormone levels differ significantly from those of an adult. Thyroid hormone testing is rarely prescribed. It helps to diagnose developmental disorders in the early stages and correct them.

Unlike adults, children's analysis involves checking only 2 hormones - T3 and TSH. They influence the rate of development of the baby.

So the results of TSH tests in infants should be 1.12-17.05 mIU/l.

By the age of one year, the amount of this hormone produced is less than 0.66-8.3 mIU/l.

• Up to 5 years - 6.55 mIU/l,
• Up to 12 years - 5.89 mIU/l,
• Up to 16 years - 5.01 mIU/l.

Afterwards it stabilizes at around 4.15 mIU/l.

It is worth noting that the level of thyrotropin depends on the time of day. It reaches its maximum at 3 am, and the lowest numbers are recorded at 5-6 pm.

Analyzes of thyroid hormones, decoding of triiodothyronine standards by age:

• Up to 10 years - 1.79-4.08 nmol/l,
• Up to 18 years - 1.23-3.23 nmol/l.

As you grow older, this figure decreases to 1.06-3.14. At different times of the year it is produced with different activity. In autumn and winter it is more intense, and in spring the production of T3 decreases.

Preparation for delivery of biomaterial

Preparation for hormone tests should begin about a month in advance. During this period, you should stop taking the following medications:

• Iodine-containing
• Hormonal,
• Steroids,
• Aspirin-containing.

If compliance with this condition is impossible, you must notify your doctor. This way he can correct the received data.

Preparation for analysis also includes other activities:

• Do not eat 8 hours before submitting the biomaterial. You can only drink boiled water. Mineral water is not recommended for consumption,
• There should be no physical activity on the eve of visiting the laboratory,
• Stressful situations can also distort the results of the study. Therefore, try to calm down and not be nervous on the day of your laboratory visit,
• You need to give up bad habits such as alcohol and cigarettes at least 24 hours in advance. Ideally this period is 7 days,
• One day before donating blood, you need to abstain from sexual intercourse,
• For 2-3 days, you must try to protect the body from hypothermia and overheating.

The specialist should notify you about taking tests for thyroid hormones at least 2-3 days in advance. This period of time should be spent preparing your body. This is the only way to get true and accurate results that show the real picture of the condition of the thyroid gland.

We pass the analysis

How can a person with a predisposition to endocrine diseases be tested for thyroid hormones? The answer is every 6 months to monitor your condition. For everyone else, it will be enough to visit the laboratory once every 1-1.5 years.

Blood donation for thyroid hormones is done from a vein in the elbow area.

For accurate results, it is important not only how to take the test, but also when. The nuances of this procedure are usually explained by a gynecologist or endocrinologist. On the day of blood donation, no other medical procedures should be performed. X-rays, IVs and ultrasound can distort the data.

For men, everything is simpler. They have hormonal stability, so they can donate blood any day.

Tests for thyroid hormones to determine free form T3 and T4, calcitonin, TSH and AT-TG can be taken any day for both adults and children.

The analysis timeframe is up to 5 days.

What do deviations mean?

With hyperthyroidism, a metabolic failure occurs. Here are some symptoms:

• Weight loss,
• Cardiopalmus,
• Sweating.

There are 3 types of hyperthyroidism:

• Reduction in the size of the thyroid gland and the volume of hormones produced,
• Increasing its size. The body struggles with hormone deficiency,
• Low production of hormones by the hypothalamus.

When analyzing thyroid hormones, deciphering the results can give 2 possible deviations:

• Exceeding the standards – thyrotoxicosis. The patient experiences fever, active sweating, emotional instability, tremors of the limbs, and unstable heartbeat. In this case, T3 and T4 significantly increase their concentration, and TSH decreases,
• Low digital data – hypothyroidism. Symptoms: weakness, loss of consciousness, depression, swelling, decreased potency in men, decreased likelihood of conception in women.

If the analysis for the thyroid gland showed an increased level of antibodies AT-TPO and AT-TG in the blood, this indicates an autoimmune process.

Normal T4 with low concentrations of T3 and TSH is also an alarming ratio, which shows the inability of the T4 hormone to be converted into triiodothyronine.

An elevated TSH level with low T4 indicates that the pituitary gland is not working properly. If TSH is low and other T hormones are high, then the diagnosis is obvious - hyperthyroidism.

An increase in T3 levels with a rapid decrease in TSH is observed in patients:

• With a diseased liver,
• During prolonged fasting,
• For mental and emotional trauma.

An increase in T4 occurs in a number of cases:

• If the kidneys are not functioning properly,
• Immunodeficiency,
• Obesity,
• Thyroiditis.

Low thyroxine levels are observed when:

• Diseases of the pituitary gland,
• Autoimmune thyroiditis,
• Endemic goiter.

You should pay close attention to the thyroid gland; hormone tests should be carried out regularly, taking into account the frequency of diseases of this organ. The influence of the level of hormones released is very important. They affect most internal organs, including vital ones. To obtain more accurate examination results, you need to prepare 2-3 days in advance. The results form reflects data not only on hormones secreted by the thyroid gland, but also on others - “strategically important”. Although they are produced by other organs of the endocrine system, their influence on the hormonal background of the thyroid gland is very great. All analysis data are considered not separately from each other, but as a whole. This is the only way to make a diagnosis based on the results of this analysis.