TSH level standards: are changes needed? What do deviations from the norm of TSH in women indicate? TSH hormone is at the borderline of the norm.

Every woman who wants to get pregnant should know the rate of the TSH hormone. Gynecologists and endocrinologists recommend taking an analysis to its level even at the planning stage of conception, because deviations can lead to serious problems and pathologies in the development of the fetus.

This article will talk in detail about the upper and lower limits of the normal TSH hormone, as well as how going beyond it up or down affects the health of the expectant mother and the likelihood of conception.

What is it and what is it responsible for in a woman's body?

TSH or thyroid-stimulating hormone is produced by the pituitary gland and is the main regulator thyroid gland. Its main function is to influence the synthesis of thyroxine (T4) and triiodothyronine (T3). Both of these hormones play an important role in the growth of the human body, and are also responsible for the metabolism of proteins and fats.

The secretion of the hormone is controlled by the central nervous system and cells of the hypothalamus. With insufficient production, thyroid tissue grows and increases in size. Doctors call this condition goiter.

A change in the content of a hormone in a woman's body indicates hormonal disorders and requires careful verification and control, especially at the stage of preparation for pregnancy.

How does it affect the conception and bearing of a child?

Thanks to the hormone TSH in the body of a woman, the full functioning of the reproductive system occurs. Therefore, its level is important at the stage of pregnancy planning. In addition, the level of thyroid hormones has a complex effect on all organs in the body of the expectant mother, including the reproductive system. This means that deviations from the TSH norm can reduce the possibility of conceiving and bearing a child.

Besides, high or low levels of the hormone can cause the following problems:

• violation of the laying of the thyroid gland in a child, as well as congenital hypothyroidism;
• severe course of childbirth;
• miscarriage.

When should I take a blood test for thyroid-stimulating hormone?

At the stage of pregnancy planning, women undergo a lot of tests, however, blood sampling for the TSH hormone is not included in the mandatory program. Suspicion of a deviation can be suspected by a number of symptoms. If the expectant mother observes one or more of them, you should tell the gynecologist about this.

Problems with conception, a history of thyroid disease, the appearance of incomprehensible symptoms associated with a sharp change in weight and mood swings, as well as problems with concentration and memory can be a reason to take TSH.

What should be the level of the hormone?

The norm of the TSH hormone for those planning a pregnancy should fluctuate between 0.4-4 μIU / ml. Anything above the upper limit of normal is considered a significant excess and should be of concern to a woman planning to become pregnant.

For pregnancy, the ideal indicator would be a level not exceeding 2.5 μIU / ml. Although even if it is higher, but does not go beyond the normal range, there is nothing terrible. Normally, the level of the hormone at conception itself will decrease to the desired numbers.

Is it possible to get pregnant if the indicators deviate from the norm?

Pregnancy can occur at any level of the hormone, except for critical, dangerous to life and health, which can be found out from a doctor. In other words, an increased or decreased level of TSH is not a method of protection. Another issue is that at a higher level it can lead to a number of problems during gestation. Doctors recommend bringing TSH back to normal, and only then plan a child.

If pregnancy occurs during a pathological concentration of the hormone in the body, treatment should be started as soon as possible. Timely intervention will reduce the impact of a lack or excess of the hormone on the unborn baby.

High level

Is it possible to get pregnant with an increased level of the hormone? High TSH levels (hypothyroidism) and low level T3 and T4 can lead to serious metabolic disorders in the ovaries. This causes a defect in the maturation of the follicles and a problem with ovulation. As a result, there is a possibility of developing infertility against the background of disruption of the endocrine system. Even if conception occurred with elevated TSH, there is a high probability of miscarriage or fetal developmental disorders.

Often, a doctor suspects a high TSH level when a woman is not ovulating or has not been pregnant for a long time. If the results of the analysis confirm the fears, endocrine infertility is diagnosed.

You should know that an increase in hormone levels may occur after surgery, severe intoxication of the body, adrenal dysfunction, as well as any diseases associated with the thyroid gland.

Reduced

Low hormone levels (hyperthyroidism) also negatively affect a woman's reproductive system and require treatment. Often this pathology is hereditary and is called thyrotoxicosis.

The reasons for a very low TSH (significantly less than 1 μIU / ml) may be the presence of tumors or injuries of the skull and brain, improper medication, pathology of the pituitary gland, as well as the formation of diffuse toxic goiter. Another one the reason for the low level of the hormone is a strong nervous strain. All this leads to problems in the functioning of the ovaries and, consequently, difficulties in conception.

Pregnancy with a low level of TSH is dangerous not only for the fetus, but also for the mother. Pathology causes premature birth and placental abruption, and the child can be diagnosed with heart failure.

Hyperthyroidism, unlike hypothyroidism, is more difficult to treat and requires more careful monitoring by the attending physician. In especially severe cases, surgery may be necessary.

Correction methods for planning conception

If the analysis for the TSH hormone showed a deviation, then the doctor prescribes corrective therapy. As a rule, it consists in taking hormone-containing drugs. For prevention, doctors prescribe iodine-containing drugs, for example, Iodomarin.

With hypothyroidism, a woman is selected hormonal therapy. For this, drugs like Thyroxine or Euthyrox are used.

At drug treatment hyperthyroidism, thyreostatic drugs are used like methimazole or propylthiouracil. They make it difficult to accumulate iodine, which is necessary for the secretion of thyroid hormones. In severe cases resort to surgical intervention. The part of the thyroid gland with increased secretion is removed.

Another method of treatment is radioiodine therapy. A woman takes a one-time capsule or an aqueous solution of radioactive iodine, which penetrates the thyroid cells and destroys them within a few weeks. As a rule, this method is used in conjunction with drug treatment. The correct dosage of drugs is selected exclusively by a doctor.

Useful video

We offer you to watch an informative video about the effect of the TSH hormone on pregnancy:

The TSH hormone produced by the thyroid gland has a great influence on the body of the expectant mother and the possibility of conceiving a child. If there are deviations in its indicator up or down, this is an occasion to consult a doctor and undergo a course of treatment at the stage of preparation for pregnancy. Only after the hormone level returns to normal can a woman be sure of increasing the chance of conception and eliminating risks in the process of bearing a child.

Of great importance in the process of normal development of the fetus is the full functioning of the thyroid gland of the expectant mother.

It is regulated by the pituitary gland through the production of thyroid-stimulating hormone (thyrotropin, TSH). Let's figure out what role TSH (thyroid-stimulating hormone) plays during pregnancy.

Thyrotropin is a hormone synthesized by the anterior pituitary gland.

Its main function is to stimulate the production of thyroid hormones by the thyroid gland - triiodothyronine (T3) and thyroxine (T4).

This happens due to the effect of TSH on receptors located on the surface of the thyroid follicular cells.

Thyroid hormones are responsible for metabolism, thermoregulation of the body, cell growth, the work of the cardiovascular, nervous, reproductive, and digestive systems.

There is an inverse (negative) relationship between the levels of TSH and T4 in the blood: with a decrease in the concentration of T4, the synthesis of TSH increases and vice versa. So the pituitary gland controls the functioning of the thyroid gland so that the level of its hormones is within physiological limits.

Evaluation of the amount of TSH allows you to judge the correct functioning of the thyroid gland. Why is this important during pregnancy? Until the 10th week of intrauterine development endocrine system the child does not produce thyroid hormones on his own, he receives them from his mother. With their deficiency or excess, the process of laying all the organs and systems of the baby is disrupted.

The work of the thyroid gland and pituitary gland changes after conception. Chorionic gonadotropin (hCG), synthesized by the germinal membrane, stimulates an increase in the production of T3 and T4. As a result, at the beginning of pregnancy, TSH decreases. When carrying more than one child, it may tend to zero.

After the 12th week, hCG decreases, resulting in a decrease in thyroid hormone production and an increase in TSH. Its slow gradual growth is observed throughout pregnancy.

The concentration of TSH fluctuates during the day: the upper peak occurs at 2-4 am, the lower one - at 17-19 hours. If a woman does not sleep at night, then the level of thyrotropin drops.

The level of TSH is important at the stage of pregnancy planning. If there is an increase or decrease in the concentration of thyroid hormones, this negatively affects the maturation of follicles, the development corpus luteum preparing the uterus for egg implantation.

A girl may experience infertility or miscarriage.

TSH levels during pregnancy are normal

The norm of thyrotropin varies depending on the duration of pregnancy:

• 1 trimester - 0.1-0.4 mU / l;
• 2 - 0.3-2.8 mU / l;
• 3 - 0.4-3.5 honey / l.

For comparison: the permissible limits of the hormone level for non-pregnant women are 0.4-4 mU / l.

Different centers use different methods for determining the level of TSH. Therefore, the figures may differ from the above. The form with the result of the analysis indicates the boundaries of the norm, it is on them that you need to focus.

In addition to the level of TSH, it is advisable to determine the concentration of free thyroxine during the period of bearing a child. Its norm is 11.5-22 pmol / l. In pregnant women, T4, as a rule, is at the maximum limit or slightly exceeds it.

A slight deviation in the levels of TSH and T4 from the norm, as a rule, does not indicate the presence of a serious pathology. In any case, the interpretation of the results is the task of the doctor. To establish the causes of hormonal fluctuations, the use of other diagnostic methods is required - ultrasound of the thyroid gland, biopsy (if a node is detected), and so on.

The level of hormones in the body must be balanced. Both increased and reduced content of them leads to various pathologies. This topic will be devoted to the causes of low TSH.

Deviations from the norm

TSH elevated

Exceeding the upper limit of the norm of thyrotropin indicates that the thyroid gland of a pregnant woman produces an insufficient number of thyroid hormones. This condition, called hypothyroidism, can lead to miscarriage or a child with a reduced IQ. In addition, an excess of TSH, which is observed for a long time, can provoke the growth of gland tissues.

The main reasons for the increase in TSH:

• chronic autoimmune thyroiditis;
• operations on thyroid gland;
• radioiodine therapy;
• iodine deficiency;
• pituitary tumors;
• diseases of the adrenal glands;
• severe gestosis;
• poisoning with toxic substances;
• the use of certain medicinal substances - iodine preparations, neuroleptics, beta-blockers.

The tactics of correcting the level of TSH is determined by the reasons for its growth. Most often, iodine-containing drugs are prescribed (in mild cases) or an artificial analogue of thyroxine - levothyroxine.

Low TSH during pregnancy

As already noted, a decrease in TSH levels in the first trimester is a physiological phenomenon. But if a low concentration of the hormone is observed at a later date, this may indicate excessive production of thyroid hormones - hyperthyroidism. The diagnosis is confirmed by analysis of T3 and T4.

Hyperthyroidism can lead to thyrotoxicosis - poisoning of the body. The consequences of this may be placental abruption, abortion, the formation of various defects in the fetus.

Reasons for a decrease in TSH:

• diffuse toxic goiter;
• stress, starvation, exhaustion of the body;
• toxic adenoma of the thyroid gland;
• injuries and pathologies of the pituitary gland;
• taking certain hormonal drugs.

With thyrotoxicosis, thyreostatics are prescribed - substances that suppress the hyperfunction of the thyroid gland. The main drugs are methimazole and propylthiouracil. In severe cases, part of the gland is removed.

A significant deviation in the level of thyrotropin from the norm during pregnancy is an alarming sign that can be caused by various pathologies. Their treatment must be supervised by a doctor.

Signs of deviation from the norm

Clinical manifestations of an increase or decrease in the level of thyrotropin depend on the functional status of the thyroid gland. With slight fluctuations, they can be hardly noticeable.

Signs of hypothyroidism:

• fatigue, weakness;
• depressed mood;
• insomnia or too much sleep;
• loss of appetite, which is accompanied by excessive weight gain;
• pallor;
• chills;
• decreased memory and concentration;
• constipation.

Symptoms of hyperthyroidism:

• tachycardia, hypertension;
• nervousness;
• sensation of heat;
• diarrhea;
• weight loss with increased appetite;
• trembling in limbs.

Many of the symptoms described can be observed in a normal pregnancy. Do not neglect the planned examination by the endocrinologist and the delivery of an analysis for the level of TSH.

TSH analysis during pregnancy

1. For 3 days, stress factors, heavy physical exertion should be excluded, as well as not overheating or overcooling. In addition, smoking and alcohol are prohibited.
2. For 5-7 days, in agreement with the attending physician, it is necessary to stop taking hormones and iodine preparations, including vitamin complexes that contain it.

Blood sampling from a vein to calculate the level of TSH is carried out in the morning (before 11:00) on an empty stomach: you can not eat for 12 hours, you are allowed to drink water. It is important to sleep well.

If monitoring of the dynamics of thyrotropin levels is required, it is advisable to take tests at the same time in the same laboratory.

Thyroid-stimulating hormone analysis - effective method evaluation of thyroid function. After conception, it is of particular importance, since thyroxine and triiodothyronine affect the formation of the central nervous system of the unborn child. Deviations from the norm according to the result of the study cannot be a reason for terminating the pregnancy. Modern methods Treatments allow you to completely neutralize the hormonal imbalance and ensure the full development of the baby.

The hormones TSH and T4 regulate the functioning of the thyroid gland. concentrations in the blood in men, women and children, we will consider in more detail. As well as short information about what facts can affect the functioning of the thyroid gland.

Symptoms and treatment of nodular goiter of the thyroid gland will be considered in the rubric.

Related video

Maintaining normal levels of thyroid-stimulating hormone is important for health, since it regulates the functioning of the thyroid gland. The coherence of the work of other body systems depends on the functioning of this tiny organ. The concentration of TSH in the blood fluctuates not only as you grow older, but throughout the day, and deviations from the norm up or down indicate the presence serious illnesses. So, what should be the level of the hormone TSH and when should you take tests?

Daily and age norms

During the day, there are significant fluctuations in the hormone TSH, and the norm in this case is from 0.5 to 5 mU / ml. Greatest value TSH concentration reaches from midnight to 4 am. Minimum indicators observed in the daytime after 12 noon.

Important! Despite the rather large difference between the lower and upper limits of the norm, the amount of hormones T3 and T4 remains at the same level.

The norm depends not only on the time of day, but also on age. The highest rates fall on infants up to 1 month of age, ranging from 1.1 to 11 mU / l. Then, gradually, the concentration of TSH becomes lower, and after 14 years and in adult women, the lower and upper limits are 0.4 and 4 mU/l, respectively.

Norms for women

Why do you need to take an analysis?

Since TSH regulates the functioning of the thyroid gland, its concentration can be used to judge the work of this organ. If there are symptoms of endocrine disorders, the specialist will refer the patient for examination. In what cases is an analysis for the level of TSH given:

• prolonged depression;
• fatigue and indifference to the outside world;
• excessive emotionality, irritability;
• hair loss;
• decreased libido;
• inability to conceive (provided that both partners are healthy);
• enlarged thyroid gland;
• delayed physical and mental development in childhood.

All of these symptoms are associated with hormonal disorders, but sometimes TSH is sent for analysis in the following cases:

• to prevent intrauterine growth retardation;
• to assess the risk of congenital diseases;
• for the diagnosis of physical and mental development;
• to monitor the effectiveness of treatment;
• with hormone therapy to monitor changes in the body;
• as a prophylaxis in order to prevent chronic pathologies of the thyroid gland.

Decreased TSH

If a woman does not have any diseases associated with the hormonal system, regular preventive examinations can be carried out twice a year.

The accuracy of the blood test allows you to make the correct diagnosis and start the necessary treatment. In order for the results of the study to be as accurate as possible, you should carefully prepare for the procedure:

1. Two days before the analysis, you can not smoke and drink alcohol.
2. Tests must be taken before noon, because after this time the level of TSH in the blood is at a minimum, which can lead to false results.
3. Blood should be taken on an empty stomach, but if for some reason this is not possible (pregnancy or some diseases with a strict diet), this item can be skipped.
4. A few days before donating blood, you need to reduce physical activity.
5. Thanks to modern technologies the results of the analyzes are obtained as accurate and detailed as possible. A transcript with indicators of the norm and deviations from it is applied to the result obtained. This allows faster and more accurate diagnosis.

When the level is raised

Exceeding the upper limit of the TSH norm is often associated with a malfunction of the pituitary gland responsible for the production of this hormone. But there may be other reasons:

• dysfunction of the adrenal glands;
• inflammation or swelling of the thyroid gland, pituitary gland;
• complications during pregnancy;
• mental illness;
• improper distribution of physical activity;
• lack of iodine;
• genetics.

Here are the main symptoms that indicate an excessive concentration of TSH in the blood:

• severe sweating;
• weight gain;
• insomnia;
• body temperature can drop to 35;
• tiredness and fatigue;
• thickening of the neck.

Decryption

To bring the level of TSH back to normal, treatment is prescribed using drugs based on thyroxine (Euterox, Thyreotom, etc.). The dosage of the drug is prescribed only by the attending physician; in no case can you take them yourself without a prescription - this can only aggravate the problem.

Important! If medical treatment fails, surgical methods may be used.

AT traditional medicine there are also drugs that help lower TSH levels. Usually this herbal decoctions chamomile and rosehip. However, the application medicinal herbs for treatment, it is imperative to agree with the doctor and first find out if there is an allergy to any of the components.

If the level is too low

If TSH is significantly lower than normal, most often this indicates problems with the thyroid gland, in particular in the presence of benign and malignant tumors. Other possible diseases:

• meningitis;
• encephalitis;
• Plummer's disease;
• Graves' disease, etc.

Often a woman with low TSH may complain of:

• severe headaches;
• constant feeling of hunger;
• weakness;
• sleep disorders;
• tachycardia;
• trembling in the limbs;
• swelling, especially on the face;
• violations menstrual cycle;
• high BP.

If at least a few of these symptoms appear, you should definitely consult a doctor and check the blood for TSH.

Miscellaneous indicators

With a low level of the hormone, the emphasis in treatment is on the disease that provoked the hormonal disorder. Medical therapy appointed only after passing all the necessary studies. TSH can also be increased by folk remedies by eating red and black mountain ash, sea kale, etc.

TSH concentration in pregnant women

The norm of thyroid-stimulating hormone is constantly changing with each trimester, while small deviations are not a reason for a visit to a specialist. So, TSH is always lower during pregnancy with two, three or more children. But if the concentration of the hormone sharply and greatly increased in the first weeks of pregnancy, you should consult a doctor.

In different trimesters, the concentration of TSH is different, here are the limits of the norm for each period (mU / l):

• the first - from 0.1 to 0.4;
• the second - from 0.2 to 2.8;
• the third - from 0.4 to 3.5.

The lowest concentration of TSH occurs in the first weeks of pregnancy. This is due to an increase in the amount of immanent hormones produced by the thyroid gland. Further, until childbirth, the level of thyroid-stimulating hormone will gradually increase, this is important for the normal development of the fetus. Elevated TSH levels can be caused by severe toxicosis in the late period.

Treatment

With increased or reduced content TSH treatment only a doctor prescribes, while for each patient it is strictly individual. To make a diagnosis, in addition to a blood test, an ultrasound examination of the thyroid gland is necessary to identify the presence of pathology.

The course of treatment with medications is long from six months to many years throughout life. The complexity of the treatment is complemented by the fact that it is important to select the necessary doses with filigree accuracy. Even a small mistake in the dosage of the drug can lead to serious consequences.

In no case should you self-medicate and self-diagnose.

The same applies to folk remedies- many mistakenly believe that there will be nothing terrible from "herbs", but this is not so. There are many active substances in herbs, which, instead of the expected benefits, may well be harmful if the dosage is incorrect or the storage methods are incorrect.

So, it is necessary to monitor the norm of TSH. It is best to consult a doctor not when the first symptoms of abnormalities appear, but to undergo regular examinations on a voluntary basis. Disease prevention is much better than long, complicated and often expensive treatment.

REFERENCE LIMITS TSH AND THYROID

HORMONES DEPENDING ON AGE AND TERM

PREGNANCY (95% CI)

NOTE: TSH conversion factor: 1 μIU / ml \u003d 1 mU / l.

Rates may vary when using various standard commercial kits.

HOW TO PREPARE FORSTUDY OF THE FUNCTIONAL ACTIVITY OF THE THYROID GLAND IN THE CLINICAL DIAGNOSTIC LABORATORY

1) The study is performed in the morning on an empty stomach - at least 8-12 hours should elapse between the last meal and blood sampling. In the evening of the previous day, a light dinner is recommended. It is advisable to exclude fatty, fried and alcohol from the diet 1-2 days before the examination. If a feast was held the day before or there was a visit to a bath or sauna, it is necessary to postpone the laboratory test for 1-2 days. You must refrain from smoking 1 hour before blood sampling.

2) You should not donate blood after X-ray studies, physiotherapy procedures.

3) It is necessary to exclude factors that affect the results of the research: physical stress (running, climbing stairs), emotional arousal. Before the procedure, you should rest for 10-15 minutes and calm down.

4) It must be remembered that the result of the study may be distorted by the action of the accepted medicines or their metabolic products. The appointment and cancellation of any drug is accompanied by a change in laboratory parameters. Therefore, before taking the analysis, you should consult your doctor about the possibility of limiting the intake of medications in preparation for the study. It is recommended to refuse to take medications before donating blood for research, that is, blood is taken before taking medications.

5) Taking into account the daily rhythms of changes in blood parameters, it is advisable to conduct repeated studies at the same time.

6) In different laboratories can be applied different methods research and units of measurement. In order for the assessment of the examination results to be correct and the results to be acceptable, it is desirable to conduct studies in the same laboratory at the same time.

Research on thyroid hormones. 2 - 3 days before the study, the intake of iodine-containing drugs is excluded, 1 month - thyroid hormones (in order to obtain true basal levels), unless there are special instructions from the endocrinologist. However, if the purpose of the study is to control the dose of thyroid hormone preparations, blood sampling is performed while taking the usual dose. It should be borne in mind that taking levothyroxine causes a transient significantly increased content of total and free thyroxine in the blood for about 9 hours (by 15-20%).

Test for thyroglobulin it is advisable to carry out at least 6 weeks after thyroidectomy or treatment. If such diagnostic procedures like a biopsy or thyroid scan, then the study of the level of TG in the blood must be strictly carried out before the procedures. Since patients after radical treatment of differentiated thyroid cancer receive high doses of thyroid hormones (to suppress the secretion of TSH), against which the level of TG also decreases, its concentration should be determined 2–3 weeks after discontinuation of suppressive therapy with thyroid hormones.

THYROTROPIC HORMONE (TSH, THYROTROPIN)

TSH is the reference criterion for the laboratory assessment of thyroid function. It is with him that diagnostics should be started if deviations in the hormonal activity of the thyroid gland are suspected. TSH is a glycoprotein hormone that is produced in the anterior pituitary gland and stimulates the synthesis and iodination of thyroglobulin, the formation and secretion of thyroid hormones. The pituitary secretion of TSH is very sensitive to changes in the concentration of T 3 and T 4 in the blood serum. A decrease or increase in this concentration by 15-20% leads to reciprocal shifts in TSH secretion (feedback principle).

The existence of a dependence of the formation and secretion of TSH on the action of drugs, the daily rhythm of changes in the level of TSH, the state of stress and the presence of somatic diseases in the patient should be taken into account when interpreting the results of the study.

The biological half-life of TSH is 15-20 minutes.

INDICATIONS FOR THE DETERMINATION OF TTG: diagnosis of thyroid dysfunction, different kinds hypothyroidism, hyperthyroidism, mental retardation and sexual development in children, cardiac arrhythmias, myopathy, depression, alopecia, infertility, amenorrhea, hyperprolactinemia, impotence and decreased libido.

Monitoring the condition of patients on hormone replacement therapy: TSH secretion is suppressed during standard therapy or during postoperative replacement therapy.

Normal or elevated levels of TSH indicate an inadequate dose of the drug, incorrectly administered hormonal therapy, or the presence of antibodies to thyroid antigens. During replacement therapy for hypothyroidism, the optimal level of TSH is within the lower reference values. During replacement therapy, blood for TSH testing must be taken 24 hours after the last dose of the drug.

Screening for congenital hypothyroidism: On the 5th day of a child's life, the level of TSH in the blood serum or a blood spot on filter paper is determined. If the TSH level exceeds 20 mIU/L, a new blood sample should be retested. With a TSH concentration in the range of 50 to 100 mIU / L, there is a high probability of the presence of the disease. Concentrations above 100 mIU/L are typical of congenital hypothyroidism.

PHYSIOLOGICAL CONDITIONS LEADING TO CHANGES IN THE LEVEL OF TSH IN THE BLOOD

In healthy newborns at birth, there is a sharp rise in the level of TSH in the blood, decreasing to a basal level by the end of the first week of life.

In women, the concentration of TSH in the blood is higher than in men by about 20%. With age, the concentration of TSH increases slightly, the number of hormone emissions at night decreases. Elderly people often have low TSH levels and in these cases it is necessary to take into account low sensitivity to stimulation.

TSH levels increase during pregnancy (oral contraceptives and the menstrual cycle do not affect the dynamics of the hormone)

TSH is characterized by diurnal fluctuations in secretion: the highest values ​​of TSH in the blood reaches 24 - 4 o'clock in the morning, in the morning the highest level in the blood is determined at 6 - 8 o'clock. The minimum TSH values ​​​​are determined at 15 - 18 pm. The normal rhythm of TSH secretion is disturbed when awake at night. The interval after taking levothyroxine does not affect the level of TSH. It is recommended to repeat the analysis if the obtained results do not correspond to clinical picture and parameters of other studies.

In middle-aged women and old men, the maximum peak of TSH in blood serum occurs in December.

With menopause, there may be an increase in the content of TSH with an intact thyroid gland.

DISEASES AND CONDITIONS IN WHICH CHANGES IN THE LEVEL OF TSH IN THE BLOOD ARE POSSIBLE

CLINICAL AND DIAGNOSTIC SIGNIFICANCE OF TSH

· In treated hyperthyroid patients, TSH may remain low for 4-6 weeks after reaching the euthyroid state.

· In pregnant women and women taking contraceptives, normal TTT levels and elevated levels of T 3 and T 4 occur with euthyroidism.

· The absence of primary thyroid disease can be stated in any patient with a normal TSH and T 4 in combination with an isolated deviation (in any direction) T 3 .

In severe patients with normal concentrations of T4 and T3, TSH production may be impaired.

· TSH secretion is suppressed during treatment with thyroxine and in postoperative replacement therapy. Normal or elevated levels of TSH in these cases indicate a low dose of the drug, peripheral resistance to thyroid hormones, or the presence of antibodies to thyroid hormones.

· During replacement therapy for hypothyroidism, the optimal level of TSH should be below the reference values.

MAIN CRITERIA FOR THE DIFFERENTIAL DIAGNOSIS OF SUBCLINICAL HYPOTHYROISIS

MEDICINES THAT AFFECT THE LEVEL OF TSH IN THE BLOOD

THIROXIN (T 4)

Thyroxine is a thyroid hormone, the biosynthesis of which occurs in the follicular cells of the thyroid gland under the control of TSH. The main fraction of organic iodine in the blood is in the form of T 4 . About 70% of T 4 is associated with thyroxine-binding globulin (TC), 20% with thyroxine-binding prealbumin (TSPA) and 10% with albumin. Only 0.02 - 0.05% T 4 circulates in the blood in a protein-free state - the free fraction of T 4. The concentration of T 4 in serum depends not only on the rate of secretion, but also on changes in the binding capacity of proteins. Free T 4 is 0.02 - 0.04% of total thyroxine.

The period of biological half-life T 4 - 6 days.

PHYSIOLOGICAL STATES LEADING TO CHANGES IN THE LEVEL OF T 4 IN THE BLOOD

In healthy newborns, the concentration of free and total T 4 is higher than in adults.

Hormone levels in men and women remain relatively constant throughout life, declining only after age 40.

During pregnancy, the concentration of thyroxin increases, reaching maximum values ​​in the 3rd trimester.

During the day, the maximum concentration of thyroxine is determined from 8 to 12 hours, the minimum - from 23 to 3 hours. During the year, the maximum values ​​of T 4 are observed between September and February, the minimum in the summer.

DISEASES AND CONDITIONS IN WHICH CHANGES IN THE LEVEL OF T 4 IN THE BLOOD ARE POSSIBLE

Hemolysis, repeated thawing and freezing of serum can lead to a decrease in T 4 results. High serum bilirubin concentrations tend to overestimate the results. The presence of the preservative EDTA gives falsely high results for free T 4 . Starvation, poor diet with low protein content, lead exposure, heavy muscle exercise and training, excessive physical effort, various types of stress, weight loss in obese women, surgery, hemodialysis can contribute to a decrease in total and free T 4 . Hyperemia, obesity, interruption of heroin intake (due to an increase in transport proteins) cause an increase in T 4 , heroin reduces free T 4 in blood serum. Smoking causes both a decrease and an overestimation of the results of the study on thyroxine. The imposition of a tourniquet when taking blood with work and without "hand work" causes an increase in total and free T 4 .

Umbilical vein T4 levels are lower in preterm compared to term infants and are positively correlated with birth weight of term infants. High values ​​of T 4 in newborns are caused by elevated TSH, free T 4 is close to the level in adults. The values ​​rise sharply in the first hours after birth and gradually decrease by the age of 5. In men, there is a decrease during puberty, in women this is not observed.

The concentration of free T 4, as a rule, remains within the normal range at serious illnesses, not associated with the thyroid gland (the concentration of total T 4 may be reduced).

DISEASES AND CONDITIONS IN WHICH CHANGES IN THE LEVEL OF TOTAL T 4 ARE POSSIBLE

CLINICAL AND DIAGNOSTIC SIGNIFICANCE T 4

An isolated increase in total T 4 against the background normal values TSH and T3 may be a rare finding. This appears to be a patient with normal thyroid function but congenital excess hepatic production of thyroid hormone carrier proteins.

· with "isolated" T 3 -hyperthyroidism, the level of free and total T 4 is within the normal range.

· at the initial stage of hypothyroidism, the level of free T 3 decreases earlier than the total T 4 . The diagnosis is confirmed in the case of an increase in TSH or an excessive response to TRH stimulation.

· A normal T4 level is not a guarantee of normal thyroid function. T 4 within the normal range can be with endemic goiter, suppressive or replacement therapy, with a latent form of hyperthyroidism or a latent form of hypothyroidism.

· In case of hypothyroidism, thyroxin contributes to the normalization of TSH and T 4. Increased concentrations of total and free T 4 and the concentration of TSH in the region of the lower limit of the norm are observed during the selection of adequate replacement therapy.

· during thyreostatic therapy, the level of T 4 in the region of the upper limit of the norm indicates an adequate choice of a maintenance dose.

· An elevated level of free T 4 does not always indicate a violation of the function of the thyroid gland. This may be due to taking certain medications or serious general diseases.

MEDICINES AFFECTING THE LEVEL OF TOTAL T 4 IN THE BLOOD

MEDICINES THAT AFFECT FREE T 4 LEVEL

DISEASES AND CONDITIONS IN WHICH CHANGES IN THE LEVEL OF FREE T 4 ARE POSSIBLE

TRIODOTHYRONINE (T 3)

Triiodothyronine is a thyroid hormone that is 58% iodine. Part of the serum T 3 is formed by enzymatic deiodination of T 4 in peripheral tissues, and only a small amount is formed by direct synthesis in the thyroid gland. Less than 0.5% of T 3 circulating in serum is in free form and biologically active. The remaining T 3 is in a reversible relationship with serum proteins: TSH, TSPA and albumin. The affinity of T 3 to whey proteins is 10 times lower than T 4 . In this regard, the level of free T 3 does not have such a great diagnostic value as the level of free T 4 . At least 80% of circulating T3 is derived from T4 monodeiodization in peripheral tissues. T 3 is 4-5 times more active in biological systems than T 4 . Although the minimum serum concentrations of T 3 100 times lower than the concentration of T 4 , most immunoassays have little cross-reactivity with T 4 . Since T3 levels change rapidly under the influence of stress or other non-thyroid factors, T3 measurement is not the best general test for determining thyroid status. Free T 3 is about 0.2 - 0.5% of the total T 3.

The biological half-life T 3 is 24 hours.

INDICATIONS FOR THE DETERMINATION OF T 3

differential diagnosis of thyroid diseases,

control study with isolated T 3 -toxicosis,

The initial stage of hyperfunction of the thyroid gland, in particular autonomous cells,

acute hyperthyroidism after suppressive thyroxine therapy,

relapse of hyperthyroidism.

To exclude an overdose of drugs, it is necessary to control the level of T 3, which should be within the normal range.

PHYSIOLOGICAL STATES LEADING TO CHANGES IN THE LEVEL OF T 3 IN THE BLOOD

The concentration of T 3 in the blood serum of newborns is 1/3 of its level observed in adults, but already within 1-2 days it increases to the concentration detected in adults. In early childhood, the concentration of T 3 decreases slightly, and in adolescence(by the age of 11-15) again reaches the level of an adult. After 65 years, there is a more significant decrease in the level of T 3 compared with T 4 . Women have lower concentrations of T 3 than men, on average by 5-10%.

During pregnancy (especially in the 3rd trimester), the concentration of T 3 in the blood increases by 1.5 times. After childbirth, hormone levels return to normal within 1 week.

The T 3 indicators are characterized by seasonal fluctuations: the maximum level falls on the period from September to February, the minimum - in the summer period.

DISEASES AND CONDITIONS IN WHICH CHANGES IN THE LEVEL OF T 3 IN THE BLOOD ARE POSSIBLE

DISEASES AND CONDITIONS IN WHICH CHANGES TOTAL T 3 ARE POSSIBLE

MEDICINES AFFECTING TOTAL T 3

DISEASES AND CONDITIONS IN WHICH CHANGES IN FREE T 3 ARE POSSIBLE

MEDICINES THAT AFFECT FREE T 3 LEVEL

CLINICAL AND DIAGNOSTIC SIGNIFICANCE T 3

· With iodine deficiency, a compensatory increase in total and free T 3 is observed. Thus, the body adapts to the lack of "raw materials". Providing a sufficient amount of iodine entails the normalization of T 3 . These individuals do not require any treatment. Misinterpretation of an elevated level of T 3 as T 3 -toxicosis, despite normal TSH and sometimes even reduced T 4 , can lead to unreasonable prescription of thyreostatics, which is a gross mistake.

· with hypothyroidism, the levels of total and free T 3 can be in the region of the lower limit of the norm for a long time, since the increased peripheral conversion of T 4 to T 3 compensates for the decrease in T 3 .

The normal level of T 3 can be with hidden functional defects of the thyroid function, with hypothyroidism, compensated for the conversion of T 4 to T 3 .

· During goiter treatment or postoperative thyroxine replacement, TSH and T3 levels are measured to prevent dosing.

· in the treatment of hypothyroidism with thyroxine, the increase in T3 is much less compared to T4. With the introduction of large doses of thyroxine, TSH is suppressed to unrecordable values. To exclude an overdose of drugs, an analysis of the level of T 3 is carried out, which should be within the normal range.

· at the beginning of the course of thyreostatic therapy, the level of T 3 may increase as a result of compensation processes.

· determination of the level of T 3 in serum has low sensitivity and specificity in hypothyroidism, since the activation of the conversion of T 4 to T 3 maintains the level of T 3 within the normal range until the development of severe hypothyroidism. Patients with NTZ or in a state of energy hunger have low rates with T 3 and about T 3 . T3 should be measured in conjunction with free T4 in the diagnosis of complex and unusual manifestations of hyperthyroidism or some rare conditions. High T3 levels are common and early sign relapse of Graves' disease. A high or normal level of T 3 occurs in hyperthyroidism in patients with NTZ against the background of a decrease in the content of TSH (less than 0.01 mIU / l). A high or normal T3 level occurs in cordarone-induced hyperthyroidism.

ALGORITHM FOR LABORATORY EVALUATION OF A FUNCTION

THYROID GLAND

SOURCES AND MECHANISMS OF ACTION OF ORGANIC

COUNTERTHYROID DRUGS

TYPES OF SYNDROME OF NON-THYREOID DISEASES,

THEIR SIGNIFICANCE AND DEVELOPMENT MECHANISMS

DRUG INTERACTIONS AFFECTING

ON THE EFFICIENCY OF THIROXIN THERAPY

CLINICAL SITUATIONS THAT CHANGE

NEED FOR THIROXIN

MEDICINES AFFECTING

THYROID FUNCTION

PATIENTS TAKING AMIODARON (CORDARON)

Before treatment, it is necessary to study the basal level of TSH and anti-TPO. The content of free T 4 and free T 3 is checked if the level of TSH is changed. An increase in the level of anti-TPO is a risk factor for thyroid dysfunction during cordarone therapy.

During the first 6 months after the start of therapy, TSH levels may not match the level of peripheral thyroid hormones (high TSH / high free T 4 / low free T 3). If euthyroidism is maintained, TSH levels will usually return to normal over time.

Long term observation. The level of TSH during therapy with cordarone should be determined every 6 months. It is the level of TSH in such conditions that is a reliable indicator of thyroid status.

Reception of amiodarone initially causes changes in the level of TSH in the direction of increase. This is followed by the dynamics of the levels of reverse T 3, T 4 and T 3. The progressive decrease in the level of T 3 reflects a violation of the peripheral conversion of T 4 to T 3. An increase in the content of total and free T 4 may be associated with the stimulating effect of TSH and / or with a decrease in clearance T 4 .

PATIENTS WITH NON-THYROID

DISEASES (NTZ)

Acute and chronic NTZ have complex effects on thyroid test results. Testing should be deferred until recovery, if possible, unless there is a history of concern or symptoms of thyroid dysfunction. In seriously ill patients, as well as in intensive drug treatment, the results of some thyroid tests cannot be interpreted.

The combined determination of the level of TSH and T 4 allows the most reliable differentiation of the true primary thyroid pathology (coincidence of changes in the level of T 4 and TSH) and transient shifts caused by the NTZ themselves (discrepancy between changes in the level of T 4 and TSH).

The pathological level of free T 4 in patients with severe somatic diseases does not prove the presence of thyroid pathology. In the case of a pathological level of free T 4, it is necessary to investigate the content of total T 4. If both indicators (free T 4 and total T 4) are unidirectionally outside the normal range, thyroid pathology is possible. If the indicators of free T 4 and total T 4 diverge, then this is most likely due not to thyroid dysfunction, but to a somatic disease, medication. When a pathological level of total T 4 is detected, it is necessary to correlate given result with the severity of the somatic disease. A low level of total T 4 is typical only for severe and agonizing patients. Low total T4 in patients outside the intensive care unit suggests hypothyroidism. Elevated levels of total T 3 and free T 3 are a reliable indicator of hyperthyroidism in somatic diseases, but a normal or low T3 level does not rule out hyperthyroidism.

Determination of the level of TSH in patients with NTZ. Determining the level of TSH and T 4 (free T 4 and total T 4) is the most effective combination for detecting thyroid dysfunction in patients with somatic pathology. In such cases, TSH reference intervals should be extended to 0.05–10.0 mIU/L. The TSH level can transiently decrease to subnormal values ​​in the acute phase of the disease and increase in the convalescent phase.

DIAGNOSIS OF THYROID DISEASES

GLANDS DURING PREGNANCY

A change in the functioning of the thyroid gland in women occurs from the first weeks of pregnancy. It is influenced by many factors, most of which directly or indirectly stimulate the thyroid gland of a woman. Mostly this occurs in the first half of pregnancy.

Thyroid-stimulating hormone. Literally from the first weeks of pregnancy, under the influence of chorionic gonadotropin (CG), which has structural homology with TSH, the production of thyroid hormones of the thyroid gland is stimulated. In this regard, the production of TSH is suppressed by the feedback mechanism, the level of which during the first half of pregnancy is reduced in about 20% of pregnant women. At multiple pregnancy When the level of hCG reaches very high values, the level of TSH in the first half of pregnancy is significantly reduced, and sometimes suppressed, in almost all women. The lowest levels of TSH on average occur at 10-12 weeks of pregnancy. However, in some cases, it may remain somewhat reduced until late in pregnancy.

Thyroid hormones. Determining the level of total thyroid hormones during pregnancy is not informative, since it will always be elevated (in general, the production of thyroid hormones during pregnancy normally increases by 30-50%). The level of free T 4 in the first trimester of pregnancy, as a rule, is highly normal, but in about 10% of those with suppressed TSH levels exceed the upper limit of normal. As the duration of pregnancy increases, the level of free T 4 will gradually decrease and by the end of pregnancy it is very often low. In some patients, even without thyroid pathology and receiving individual iodine prophylaxis, later dates Pregnancy may show a borderline decrease in free T4 levels in combination with a normal TSH level. The level of free T 3 , as a rule, changes in the same direction as the level of free T 4 , but it is less often elevated.

General principles for diagnosing thyroid diseases during pregnancy.

* Combined determination of TSH and free T 4 is required.

* Determining the level of total T 4 and T 3 during pregnancy is uninformative.

* The level of TSH in the first half of pregnancy is normally lowered in 20-30% of women.

* The levels of total T 4 and T 3 are normally always elevated (approximately 1.5 times).

* Free T4 in the first trimester is slightly elevated in about 2% of pregnant women and in 10% of women with suppressed TSH.

* In the late stages of pregnancy, a low-normal or even borderline-low level of free T 4 is often determined in normal conditions with a normal level of TSH.

thyroglobulin (TG)

Thyroglobulin is a glycoprotein containing iodine. TG is the main component of the colloid of thyroid gland follicles and performs the function of accumulation of thyroid hormones. Thyroid hormones are synthesized on the surface of TG. TG secretion is controlled by TSH.

The biological half-life of TG in blood plasma is 4 days.

DISEASES AND CONDITIONS IN WHICH CHANGES IN THE LEVEL OF TG IN THE BLOOD ARE POSSIBLE

An increase in the content of triglycerides in the blood reflects a violation of the integrity of the hematofollicular barrier and is observed in diseases that occur with a violation of the structure of the gland or accompanied by iodine deficiency. The release of triglycerides into the bloodstream increases with stimulation and structural lesions of the thyroid gland. The determination of TG does not make sense in the next 2-3 weeks after the puncture biopsy, since the level of TG can be increased due to the passive release of the colloid into the blood when the gland is traumatized. The level of triglycerides rises in the short term after operations on the thyroid gland. The consumption of a large amount of iodine with food suppresses the release of thyroid hormones from the thyroid gland, shifting the balance between the formation and decay of TH in the direction of its formation and accumulation in the colloid. The level of triglycerides can be increased in DTG, subacute thyroiditis, enlargement of the thyroid gland under the influence of TSH, in some cases, benign thyroid adenoma.

The presence of anti-TG antibodies can cause false-negative results, therefore it is desirable to determine anti-TG antibodies in parallel with TG.

In patients with undifferentiated thyroid cancer, the concentration of TG in the blood rarely increases. In differentiated tumors with low functional activity, the level of TG increases to a lesser extent than in tumors with high functional activity. An increase in the level of TG was found in highly differentiated thyroid cancer. Of great diagnostic importance is the determination of the level of TG for the detection of metastases of thyroid carcinoma and dynamic monitoring of the condition of patients during the treatment of follicular carcinoma. It has also been found that thyroid cancer metastases have the ability to synthesize TG.

A decrease in the level of triglycerides in the blood after surgery or radiation therapy excludes the presence of metastases. On the contrary, an increase in the level of TG can serve as a sign of a generalized process.

Since patients after radical treatment of differentiated thyroid cancer receive high doses of thyroid hormones (to suppress the secretion of TSH), against which the level of TG also decreases, its concentration should be determined 2–3 weeks after discontinuation of suppressive therapy with thyroid hormones.

In pediatric endocrinology, the determination of TG is of great importance in the management of children with congenital hypothyroidism for the selection of a dose of hormone replacement therapy. With aplasia of the thyroid gland, when TH is not detected in the blood, the maximum dosage is indicated, while in other cases, the detection and increase in the concentration of TG suggests a reversible course of the disease, and therefore the dosage of the hormone can be reduced.

PHYSIOLOGICAL CONDITIONS LEADING TO CHANGES IN THE LEVEL OF TG IN THE BLOOD

TG values ​​in newborns are increased and decrease significantly during the first 2 years of life.

INDICATIONS FOR THE DETERMINATION OF TG

thyroid carcinoma (excluding medullary carcinoma)

Early detection of relapses and metastases of highly differentiated thyroid cancer in operated patients,

Evaluation of the effectiveness of radioiodine therapy for thyroid cancer metastases (according to the decrease in its content in the blood to normal values),

Metastases in the lungs of unknown origin,

Metastases in the bones of unknown origin, pathological fragility of bones,

The determination of TG cannot be carried out for the purpose of differential diagnosis of benign and malignant tumors of the thyroid gland.

TG CONCENTRATION IN HEALTHY PERSONS AND IN VARIOUS DISEASES OF THE thyroid gland

Healthy faces 1.5 – 50ng/ml

Thyroid cancer:

Before surgery 125.9 + 8.5 ng/ml

After surgery without metastases and relapses 6.9 + 1.8 ng/ml

Metastases and relapses of highly differentiated 609.3 + 46.7 ng/ml

thyroid cancer in operated patients

Benign tumors (before surgery) 35.2 + 16.9 ng/ml

Thyrotoxicosis (severe) 329.2 + 72.5 ng/ml

ANTIBODIES TO THYROOGLOBULIN (ANTI-TG)

The thyroid gland, containing specific antigens, can bring the body's immune system into a state of auto-aggression. One such antigen is thyroglobulin. Damage to the thyroid gland in autoimmune or neoplastic diseases can cause TG to enter the bloodstream, which, in turn, leads to the activation of the immune response and the synthesis of specific antibodies. The concentration of anti-TG varies over a wide range and depends on the disease. Therefore, the determination of the concentration of anti-TG can be used to diagnose and monitor the treatment of thyroid diseases.

DISEASES AND CONDITIONS IN WHICH ANTI-TG LEVEL CHANGES IN THE BLOOD ARE POSSIBLE

Anti-TG is an important parameter for the detection of autoimmune thyroid diseases and is carefully measured during disease monitoring. An increase in the level of anti-TG is determined in Hashimoto's thyroiditis (more than 85% of cases), Graves' disease (more than 30% of cases), thyroid cancer (45% of cases), idiopathic myxedema (more than 95% of cases), pernicious anemia(50% of cases, low titers), SLE (about 20% of cases), subacute de Quervain's thyroiditis (low titers), hypothyroidism (about 40% of cases), DTG (about 25% of cases), weakly positive result can be obtained with non-toxic goiter .

Estrogen-progesterone therapy for contraception increases the titer of antibodies to thyroglobulin and peroxidase. In women with AIT, when taking these drugs, the antibody titer is significantly higher than in people with AIT who are not taking these drugs.

An elevated anti-TG titer can be obtained in patients with non-endocrine diseases when taking drugs that affect the nature of the immune response.

In patients with Hashimoto's thyroiditis, the anti-TG titer usually decreases during treatment, but there may be patients in whom anti-TG can persist or be detected in waves with a period of about 2-3 years. Anti-TG titer in pregnant women with Graves' or Hashimoto's disease decreases progressively during pregnancy and rises briefly after delivery, peaking at 3 to 4 months. A normal anti-TG titer does not rule out Hashimoto's thyroiditis. The microsomal antibody test is more sensitive for Hashimoto's thyroiditis than the anti-TG test, especially in patients younger than 20 years of age.

The determination of anti-TG makes it possible to predict thyroid dysfunction in patients with other autoimmune endocrine diseases and in family members with hereditary organ-specific autoimmune diseases. Weak positive results commonly found in other autoimmune disorders and chromosomal disorders such as Turner's syndrome and Down's syndrome.

Positive results in some patients with hyperthyroidism suggest a combination with thyroiditis. The use of anti-TG to detect autoimmune diseases of the thyroid gland is especially justified in iodine-deficient areas.

Children born to mothers with high anti-TG titers may develop autoimmune thyroid diseases during their lifetime, which requires them to be classified as a risk group.

About 5 - 10% practically healthy people may have a low titer of anti-TG without symptoms of the disease, more often in women and the elderly, which is probably associated with the identification of individuals with subclinical forms of autoimmune thyroiditis.

INDICATIONS FOR ANTI-TG: - newborns: high titer of anti-TG in mothers, - chronic Hashimoto's thyroiditis, - differential diagnosis of hypothyroidism, - diffuse toxic goiter (Graves' disease), - postoperative management of patients with well-differentiated thyroid cancer in combination with TG, - assessment of anti-TG levels in iodine-deficient areas in serum contributes to the diagnosis of autoimmune thyroid pathology in patients with nodular goiter.

REFERENCE LIMITS - 0 - 100 mU/ml

ANTIBODIES TO THYROID PEROXIDASE

(ANTI - TPO)

The anti-TPO test is used to verify autoimmune thyroid disorders. Possessing the ability to bind to complement, anti-TPO are directly involved in auto-aggression, that is, they are an indicator of aggression. immune system towards your own body. Thyroid peroxidase provides the formation active form iodine, which is able to be included in the process of thyroglobulin iodification, that is, it plays a key role in the synthesis of thyroid hormones. Antibodies to the enzyme block its activity, as a result of which the secretion of thyroid hormones, mainly thyroxine, decreases. Anti-TPO is the most sensitive test for detecting autoimmune thyroid diseases. Usually their appearance is the first shift that is observed during the development of hypothyroidism due to Hashimoto's thyroiditis.

DISEASES AND CONDITIONS IN WHICH ANTI-TPO LEVEL CHANGES ARE POSSIBLE

Autoimmune diseases of the thyroid gland are the main factor underlying hypothyroidism and hyperthyroidism and develop in genetically predisposed individuals. Thus, measurement of circulating anti-TPO is a marker of genetic predisposition. The presence of anti-TPO and an elevated TSH level can predict the development of hypothyroidism in the future.

A high concentration of anti-TPO is observed in Hashimoto's thyroiditis (sensitivity 90–100%) and Graves' disease (sensitivity 85%). The level of anti-TPO increases by 40-60% in DTG, but in a lower titer than in the active stage of Hashimoto's thyroiditis.

Detection of anti-TPO during pregnancy suggests the mother's risk of developing postpartum thyroiditis and possible impact on the development of the child.

At low concentrations, anti-TPO can occur in 5-10% of the healthy population and in patients with diseases not associated with the thyroid gland, such as inflammatory rheumatic diseases.

The anti-TPO titer increases during treatment with estrogen-progesterone drugs and taking drugs that affect the nature of the immune response.

INDICATIONS FOR ANTI-TPO

autoimmune thyroiditis,

Prediction of the risk of hypothyroidism with an isolated increase in the level of TSH,

Ophthalmopathy: an increase in the periocular tissues (suspicion of "euthyroid Graves' disease").

Newborns: hyperthyroidism and high levels of anti-TPO or Graves' disease in the mother,

Risk factor for thyroid dysfunction during therapy with interferon, interleukin-2, lithium preparations, cordarone,

Risk factor for miscarriage and miscarriage.

REFERENCE LIMITS - 0 - 30 IU / ml.

ANTIBODIES TO THE MICROSOMAL FRACTION

(ANTI-MF)

Autoantibodies to the microsomal fraction are detected in all types of autoimmune thyroid diseases, however, they can also be detected in healthy people. Anti-MF is a cytotoxic factor that directly causes damage to thyroid cells. The microsomal antigen is a lipoprotein that makes up the membranes of the vesicles containing thyroglobulin. Autoimmune thyroiditis is a disease that is characterized by the formation of antibodies to various components of the thyroid gland with the development of its lymphoid infiltration and the growth of fibrous tissue. Anti-MF can destroy the thyroid gland and reduce its functional activity.

DISEASES AND CONDITIONS IN WHICH ANTI-MF LEVEL CHANGES ARE POSSIBLE

The highest levels of anti-MF are found in patients with Hashimoto's AIT (in 95% of patients), idiopathic mexidema, at the last stage of chronic atrophic thyroiditis, especially in elderly women, and are quite common in patients with an untreated form of Graves' disease. Anti-MF are determined in 85% of patients with DTG, which indicates its autoimmune genesis. Anti-MF is sometimes detected in thyroid cancer. Elevated Levels anti-MF during the 1st trimester of pregnancy indicate a certain degree of risk of postpartum thyroiditis.

INDICATIONS FOR ANTI-MF

Hashimoto's thyroiditis

Autoimmune nature of thyroid diseases,

Prognosis of postpartum thyroiditis in high-risk women

A high degree of risk of thyroiditis with a hereditary predisposition to this disease, in other forms of autoimmune processes ( diabetes type 1, Addison's disease, pernicious anemia).

ANTIBODIES TO TSH CRECEPTORS(TTT- RP)

Thyroid-stimulating hormone receptors are membrane structures of thyrocytes (and, possibly, cells of other organs and tissues). TSH-RP are regulatory proteins integrated in the thyroid cell membrane and affecting both TG synthesis and secretion and cell growth. They specifically bind the pituitary TSH and ensure the implementation of its biological action. The cause of the development of diffuse toxic goiter (Graves' disease) is the appearance in the blood of patients of special immunoglobulins - autoantibodies that specifically compete with TSH for binding to thyrocyte receptors and are capable of exerting a stimulating effect on the thyroid gland, similar to TSH. The detection of a high level of autoantibodies to TSH receptors in the blood of patients with Graves' disease is a predictive harbinger of disease recurrence (85% sensitivity and 80% specificity). Fetoplacental transfer of these antibodies is one of the causes of congenital hyperthyroidism in newborns if the mother suffers from Graves' disease. To obtain evidence of the reversible nature of the disease, laboratory monitoring is required to establish the elimination of antibodies to TSH-RP from the child's body. The disappearance of antibodies in a child after medical achievement of euthyroidism and elimination of goiter serves as the basis for deciding whether to stop drug therapy.

Autoantibodies to TSH receptors in increased amounts can be detected in patients with Hashimoto's goiter, with subacute AIT. The level of autoantibodies progressively decreases with medical treatment of these diseases or after thyroidectomy, which can be used to monitor the effectiveness of the treatment.

INDICATIONS FOR PURPOSE:

REFERENCE LIMITS: The level of autoantibodies to TSH receptors in serum is normally up to 11 IU / l.

With prices for complexes laboratory research can be found in the "Services and prices" section.

Take tests constantly in the same laboratory - and your doctor will approximately know your personal norm indicators and any deviation from the norm will be immediately noticed by him.

The article provides information about what tests for TSH hormones are, in what cases they are prescribed, what is the instruction for preparing for their conduct. Reference values ​​for patients of different age and gender are indicated. There is also a video in this article and interesting photos materials.

TSH is one of the hormones of the anterior pituitary gland responsible for the regulation of the thyroid gland. Thyrotropin is a glycoprotein whose molecular weight is approximately 28 kDa.

Its effects on the thyroid gland are multifaceted:

1. Initiation of cellular growth of thyrocytes.
2. Stimulation of the production of thyroid hormones.
3. Activation of mitotic activity of gland cells.

Determination of its content is one of the most important analyzes in the diagnosis of disorders of the glandula thyreoidea.

The production and release of thyrotropin is carried out under the influence of thyrotropin-releasing hormone, which begins to be synthesized in the hypothalamus as soon as the level of T3 (triiodothyronine) and that circulate in the peripheral blood drops. Therefore, the concentration of TSH and thyroid hormones are inversely related.

In addition, other neuronal mechanisms influence the release of thyrotropin:

1. Sleep/wake.
2. The presence of non-specific stress.
3. Reducing the ambient temperature.

The rhythm of hormone production goes astray if the subject is awake at night. During certain phases of pregnancy, there is a drop in TSH production and this is normal.

Factors affecting the concentration of TSH

If a person is forced to stay awake at night, then the release of TSH is disturbed. Also, a low level of hormone production is observed during pregnancy and breastfeeding, but this is the norm for such special conditions. At the level of production of this biologically active substance able to influence a number of medications and the pathology of some organs interconnected with glandula thyreoidea.

In addition, heavy physical exertion, severe stress, acute infectious pathologies and prolonged low-calorie diets can lead to a change in the content of thyrotropin.

Antibodies to TSH

Thyroid hormone antibodies TSH is a specific type of immunoglobulin that acts against thyroid hormone precursors. They are considered specific markers of autoimmune thyroid pathologies.

In case of any malfunction in the functioning of the immune system, antibodies to TSH, or rather to its receptors, are formed in the blood serum, which cause their death, due to which the synthesis of thyroid hormones becomes impossible, or vice versa, is carried out in excess.

There are several types of antibodies:

• increasing the synthesis of T3 and T4;
• blocking the connection of TSH with gland receptors.

An increase in antibodies to TSH is observed in diffuse toxic goiter, autoimmune thyroiditis, idiopathic myxedema, subacute thyroiditis, thyroid cancer, and other autoimmune pathologies. In addition, these antibodies stimulate the production of hormones.

If an increase in antibodies to TSH is accompanied by an increase in the level of thyroid hormones, the following symptoms occur:

• an increase in the size of the thyroid gland;
• increased production of thyroid hormones;
• exophthalmos;
• tachycardia;
• violation of the heart rhythm;
• convulsions;
• weight loss;
• muscle weakness;
• temperature rise;
• bone pain;
• hair loss;
• violation of menstrual function in women;
• erectile dysfunction in men.

In addition, with diffuse toxic goiter, there may be life threatening complication - thyrotoxic crisis.

Malfunctions in the production of thyroid-stimulating hormone

The concentration of TSH can change both up and down. These fluctuations can be caused by the state of the pituitary gland, hypothalamus and / or thyroid gland.

Some variants of the combination of diseases with the level of T3, T4 and TSH are shown in the table below:

By analyzing the hormone TSH, it is possible to identify even subclinical stages in the development of glandula thyreoidea pathologies, in which regulatory mechanisms still cope with maintaining the reference levels of T3 and T4 concentration levels. As a rule, when conducting a screening examination of the thyroid gland, the doctor may prescribe only one test for thyrotropin, or may add a test for free thyroxine to it.

Very rarely, secondary hyperthyroidism can be caused by TSH-secreting neoplasms.

Diseases that do not directly affect the organs responsible for the rate of TSH synthesis

Diseases that are not related to glandula thyreoidea, as well as medicinal substances used to treat them, can temporarily change the content of TSH in peripheral blood. As a rule, its level falls in the acute period and rises slightly during recovery.

Under such conditions, doctors use an extended reference range (0.02 - 10.00 mU/L) for TSH tests, and also determine the content of free thyroxine.

Replacement therapy

If the subject takes artificial substitutes for thyroid hormones, for example, L-thyroxine, immediately before taking biological material for analysis, the TSH level will not change, since the normalization of thyrotropin content occurs very slowly (it may take several weeks or even months of continuous medication ). The reason for this is hyperplasia of thyrotrophs, which develops against the background of chronic severe hypothyroidism.

So control replacement therapy, using the analysis for thyroid-stimulating hormone as a guide, it makes sense no less than one and a half months after the start of treatment, changing the drug or changing the dosage.

Pregnancy

During the period when a woman is preparing to become a mother, the content of thyroid-stimulating hormone in the peripheral blood may undergo physiological changes (read more). Since human chorionic gonadotropin, released during pregnancy, is structurally similar to TSH, it is quite capable of stimulating the production of thyroid hormones.

For this reason, the first trimester is characterized by a temporary increase in the concentration of thyroxin, which causes a decrease in the content of thyrotropin. In the second and third trimesters, TSH returns to normal.

Important! An increase in the concentration of thyroid-stimulating hormone in the early period indicates a possible latent hypothyroidism that can harm the fetus.

Indications for TSH testing

This study is assigned for:

• alopecia;
• myopathy;
• amenorrhea;
• depression;
• infertility;
• hypothermia;
• impotence;
• decreased libido;
• cardiac arrhythmias;
• hyperprolactinemia;
• diseases of the glandula thyreoidea;
• screening;
• delayed development of the intellectual and sexual spheres of the child;
• monitoring the patient's condition after treatment with hormone substitutes;
• conducting control tests, identified diffuse toxic goiter (frequency from one to three times in one and a half to two years), as well as identified hypothyroidism (frequency one to two times per year).

The direction is prescribed by the endocrinologist, who, in most cases, makes an assessment of the result.

Study preparation

To maximize the effectiveness of the analysis, it is important to properly prepare for it.

1. Refusal to accept hormonal drugs or multivitamin complexes containing iodine (only after the permission of the endocrinologist). If it is undesirable to interrupt the course of therapy, warn the laboratory assistant that you are taking any medication constantly.
2. Refusal to drink alcohol 2-3 days before the planned examination.
3. A light dietary dinner on the eve of blood sampling, which should be no later than 19.00.
4. Testing on an empty stomach (it is only allowed to drink a little still water when thirsty) in the morning.
5. Exclusion intensive physical activity and stress just before going to the laboratory.

In addition, answers to questions of interest to many patients can be found in the table below.

Note! Surgical interventions, X-ray exposure can negatively affect the results of the examination. After these procedures, it is advisable to postpone the analysis for thyroid hormones for 2-3 months.

Table 1: Description of the TSH assay:

Research technology

For the study, venous blood with a volume of 5 to 10 ml is used. In the case of monitoring the dynamics of changes in the concentration of TSH, the sampling of biological material should be carried out at the same time of day, since the content of the hormone in the peripheral blood is subject to daily fluctuations.

To determine the concentration of thyrotropin in the entire history of the analysis, 3 generations of analyzers have been developed. The 1st generation is practically obsolete these days, while the 2nd and 3rd are actively used by modern laboratories.

II generation of analyzers

It is based on the ELISA technology ( enzyme immunoassay). The analyzers used in this case have a number of advantages:

1. Low price.
2. Small sizes.
3. Available domestic reagents.
4. Can be used without complex automated laboratory equipment.

But the second generation also has a negative side - the low accuracy of the result obtained (the error reaches 0.5 μIU / ml). At the same time, laboratory owners set the price for such analysis only slightly less than when using next-generation analyzers.

III generation of analyzers

Here, another technology was taken as a basis - the immunochemiluminescent method. An analysis for TSH carried out with its help has an error that is 500 (!) times less than that of the second generation - 0.01 μIU / ml. Therefore, it makes sense to apply for a study on thyrotropin in laboratories practicing the use of III generation analyzers.

Deciphering the analysis

Reading the result of the study is carried out by an endocrinologist.

Reference TSH concentrations are shown in the table below:

More often, a blood test for TSH hormones is required for people undergoing hormonal changes in the body - who have reached the age of forty - the period preceding menopause. But for those sixty years old and older, such control should be carried out constantly.

The phase of the menstrual cycle does not affect the concentration of thyroid-stimulating hormone in the peripheral blood, so it can be done on any day. Analyzes should be repeated in the same laboratory complex, since reagents, equipment and technologies in different institutions may differ in both reference values ​​and units of measurement, which can confuse the reading of results.

Elevated TSH

In rare cases, an increase or decrease in TSH values ​​may be due to pituitary dysfunction.

Elevated levels of thyroid-stimulating hormone are observed with:

• Hypofunction of the thyroid gland - autoimmune thyroiditis or Hashimoto's thyroiditis. It is the most common cause primary hypothyroidism.
• Tumors of the pituitary gland, which stimulates the formation of TSH. This condition is rarely diagnosed.
• Insufficient intake of thyroid hormones during the treatment of hypothyroidism and in patients with a removed thyroid gland.
• Overdose of antithyroid drugs (thyreostatic) in patients with hyperthyroidism.

An increase in the level of thyroid-stimulating hormone relative to the norm in patients suffering from hypothyroidism and taking replacement therapy indicates an insufficient effect of the therapy or the violations that it allows. When an analysis of TSH is obtained, what should be done if its level is elevated - treatment, otherwise the risk of hypothyroidism is high.

Decreased TSH

Low TSH values ​​can result from:

• hyperthyroidism;
• damage to the pituitary gland, which does not allow the production of TSH;
• taking antithyroid drugs in insufficient dosage;
• drug overdose in the treatment of hypothyroidism;
• third trimester of pregnancy.

If the tests showed low or high TSH, this indicates a problem with the functioning of the thyroid gland, but does not clarify the cause of this condition.

The table summarizes the findings from the research findings and their potential implications:

In the thyroid gland, diseases often develop due to the formation of nodes in the tissues. It is possible to identify them at an early stage by a "happy" accident. With your own hands, it is unlikely that you will be able to feel a knot (seals) in the thyroid gland a little less than 1 cm. Treatment as such is not carried out, but regular examination by an endocrinologist is necessary.

The thyroid node is well "visible" on special equipment. If there is a rapid increase in the volume of the neck, this may indicate a more serious or malignant disease.

A very large goiter can compress the pharynx and esophagus, causing difficulty in breathing and dysphagia (difficulty swallowing food). In addition, the recurrent laryngeal nerve is affected, resulting in hoarseness.

Procedure price

Tests for the content of thyrotropin are not carried out in all clinics, since reagents are quite expensive, such tests are not performed so often, so many municipal clinics prefer not to spend money on them. But in almost all cities of the country you can find at least one laboratory, which is still involved in determining the concentration of TSH.

The price of the analysis depends on several inputs:

• generations of analyzers used by a particular laboratory;
• the size and status of the locality where the institution is located;
• qualifications of the staff of the laboratory complex.

For example, for residents of Naberezhnye Chelny, such a study will cost 200.00 rubles, Kazan - 250.00, St. Petersburg - 450.00, and Moscow - 500.00 - 2,000.00 rubles. Within one city, an analysis for TSH hormones can also cost different amounts - in sleeping areas it is cheaper, and in the center it is much more expensive.

Questions to the doctor

Elevated TSH in tests

Recently, in company with my mother (she has a goiter), I decided to get tested for the thyroid gland. I got the results: TSH - 8.2 mU / l, T3 and T4 are normal. What kind of analysis - TTG? What can his rise mean? Do I need to treat the thyroid gland, provided that I have no special complaints?

Hello! TSH is a pituitary hormone that can be called the main regulator of the thyroid gland. An increase in its concentration can have a lot of reasons, however, with normal T3 and T4 most likely indicates subclinical hypothyroidism.

I advise you to additionally undergo an ultrasound of the thyroid gland and contact an endocrinologist to resolve the issue of the need for hormone replacement therapy.

Thyrotropin changes in analyzes

Hello! For the first time examined the thyroid gland after a miscarriage for a period of 10 weeks. Then I was diagnosed with "autoimmune thyroiditis" (there were signs of inflammation on ultrasound + TSH - 9 mU / l) and prescribed Euthyrox 50 mcg. Recently passed or took place inspection - TTG - 0,024. The doctor said that it was not enough, and immediately canceled the hormones. I repeat the examination after 2 months, TSH is even lower - 0.009. With what it can be connected, in fact I do not drink hormones?

Hello! To answer this question, you need to undergo an additional examination (ultrasound, AT to rTSH and AT and TPO, St. T4). It is necessary to find out the cause of the developed thyrotoxicosis and, if necessary, start treatment with thyreostatics.

Laboratory diagnosis of hypothyroidism

Valentina, 46 years old: Hello! Recently I took tests for hormones, TSH was 18.2 μIU / ml, T4 7.3 pmol / l. A familiar physician said that the first one just rolls over. What indicators TTG norm or rate in my case? And what should I do next?

Hello! The reference values ​​​​of thyrotropin for your age are 0.3-4.0 μIU / ml, T4 St. - 10-22 pmol / l. Indeed, the level of thyrotropin significantly exceeds the norm: such a laboratory picture indicates insufficient functional activity of the thyroid gland, or hypothyroidism.

First of all, you need to do an ultrasound of the thyroid gland and contact an endocrinologist who can draw up a further plan for examination and therapy.

Planning for pregnancy with low TSH

Ekaterina, 33 years old: I have such a situation. My husband and I are planning our first pregnancy (the age is no longer young), but I have problems with the thyroid gland. TSH - 0.01. The doctor prescribed Tyrozol, but they need to be treated for at least a year. We really want a baby, can I get pregnant without taking pills?

Hello! Pregnancy on the background of thyrotoxicosis, which, judging by the level of TSH, you have, is a dangerous undertaking. Of course, conception can occur, but gross hormonal disorders are highly likely to provoke a miscarriage, premature birth and other serious consequences. Therefore, before planning a pregnancy, be sure to complete the full course of treatment and make sure that the levels of TSH and T4 have returned to normal.

TSH and pregnancy

Evgenia, 28 years old: Hello. Two years ago, I was diagnosed with hypothyroidism, I see an endocrinologist, I drink L-thyroxine at a dosage of 50 mcg per day. Now we are actively planning a pregnancy with my husband, I am going through preventive examination. According to the results of tests for hormones TSH at the upper limit of the norm, T3 and T4 are normal. The doctor insists on increasing the dose of hormones to 75 mg/day, associating this with the forthcoming pregnancy. Is it justified?

Hello Evgenia! To answer your question in detail, you need to know a lot of nuances, from the history of your disease to the dynamics of laboratory tests over the past months. But in general, I agree with your doctor: without increasing the dosage of L-thyroxine by early dates During pregnancy, you may develop subclinical and then overt hypothyroidism.

In this case, the correction of hormone therapy is a preventive measure to maintain your health and normal gestation.