What not to eat before TTG. What is TSH and how to take the prescribed test correctly? What indicators are determined during the study?

TSH is an abbreviation for thyroid-stimulating hormone, a hormone produced by the pituitary gland that stimulates the activity of the thyroid gland. It is one of the main hormones in the human body and is responsible for the full functioning of a very important organ - the thyroid gland. The hormone is produced in the brain in the pituitary gland. The substance is a stimulant for the release of thyroxine and trithyronine by the thyroid gland - hormones that are responsible for the full functioning of the main systems in the body, as well as proper fat metabolism. For this reason, disruption in the production of these hormones can have serious health consequences.

In order to detect abnormalities, a TSH blood test is indicated. Such an examination most often has to be done by women, who are 10 times more likely than men to suffer from disorders of the pituitary gland and thyroid gland. In the vast majority of cases, blood for determination of TSH hormones is donated simultaneously with blood for determination of thyroid hormones. An endocrinologist deciphers the TSH blood test. Based on its results, he prescribes treatment to the patient using certain drugs. As a rule, with properly selected therapy it is possible to short term normalize the patient's condition.

What effects does TSH have on the body?

In addition to regulating the functioning of the thyroid gland, the hormone also affects the entire body as a whole. The substance is necessary for the following processes to occur:

full production of proteins;
maintaining proper heat exchange;
activation of metabolic processes;
high-quality synthesis of nucleic acids;
high-quality synthesis of phospholipids;
proper formation of red blood cells;
correct glucose metabolism;
proper absorption of iodine by thyroid cells;
stimulation of adenylate cyclase.

Also, without the action of thyroid-stimulating hormone, full muscle activity, full thinking, oxygen saturation of tissues, and egg maturation are impossible.

Hormone levels in the blood by age

When a biochemical blood test is performed, TSH disorders are determined based on generally accepted standards. Depending on age, the hormone level changes as follows:

Sometimes in different laboratories in the analyzes of the same person there may be a discrepancy of 0.2, which is considered normal. This deviation is usually associated with the reagents that are used to test blood for thyroid-stimulating hormone.

What diseases cause an increase in hormones?

There are many reasons for increased hormones. A blood test for TSH may be elevated in the following cases:

removal of the thyroid gland;
treatment of thyroid diseases using radioactive iodine;
autoimmune diseases, in which thyroid cells are destroyed by body cells that mistake healthy tissue for pathological ones;
traumatic injuries of the thyroid gland;
particularly severe iodine deficiency;
cancerous tumors affecting the thyroid gland;
congenital insufficiency of the adrenal glands;
excessive hypothalamic function;
benign tumors of the pituitary gland;
impaired sensitivity of body tissues to hormones secreted by the thyroid gland;
severe viral infections;
severe stress;
severe physical overload;

If a person is prescribed treatment with medications that can disrupt hormone levels, it is recommended to regularly take a TSH hormone test. This will allow violations to be identified in a timely manner and the necessary adjustments to be made.

Symptoms of elevated TSH

A number of signs indicate that hormonal levels are elevated. It is necessary to take a TSH test in the following cases when:

weight gain;
swelling of the lips, eyelids, tongue and limbs;
frequent chills;
general muscle weakness;
depressive states;
frequent insomnia;
memory impairment;
slow heart rate below 55 beats per minute;
increased brittleness of nails;
excessive hair loss;
excessive paleness of the skin;
tendency to constipation;
particularly painful and scanty menstruation;
loss of sexual desire;
mastopathy.

This symptomatology is a direct indication for visiting a doctor, who will give a referral for a blood test for TSH. All symptoms appear at once only if the hormone levels are very disturbed. With mild violations, only some of the signs appear and in insignificant intensity. Despite the fact that at this moment the condition does not cause severe discomfort, it should not be ignored.

It is not difficult to guess that the pituitary gland, by increasing the synthesis of TSH, is trying to “force” the production of T3 and T4, which are clearly lacking. Therefore, first of all, a high level of TSH indicates a decrease in thyroid function - hypothyroidism, or myxedema.

Causes of low TSH

The reasons for low hormones can be different. The pathology occurs much less frequently than the previous one, but still one should not forget about it. Most often, a decreased TSH is observed with a significant increase in the level of thyroid hormones. In this case, a blood test is taken to measure the thyroid gland TSH and many other hormones. Pathology is most often caused by the following factors:

Graves' disease and hyperthyroidism (thyrotoxicosis);
tumor formations of the thyroid gland;
brain tumors;
metastasis of cancer to the pituitary gland;
traumatic brain injury;
brain inflammation;
traumatic conditions in which acute pain is present;
diseases accompanied by acute pain;
taking a series medicines.

It is not uncommon for TSH deficiency to be caused by taking medicines– analogues of thyroid hormones. For this reason, quite often the patient is prescribed a blood test for TSH hormones during the treatment period.

Symptoms of low TSH levels

It is also necessary to take a TSH test if you have symptoms of a low level. The main ones are:

weight loss;
goiter formation;
increased body temperature to a maximum of 37.5;
increased appetite;
frequent bowel movements;
tachycardia;
heart failure;
increased bone fragility;
neurasthenic mental disorders;
panic attacks;
severe muscle weakness;
not blinking often enough;
wide eyes;
sensation of a foreign body in the eyes, bulging eyes;
increased dryness of the eye mucosa;
increased skin dryness.

All these symptoms indicate hyperthyroidism. Excess thyroid hormones lead to the fact that there is no need to stimulate it, and the secretion of TSH simply stops. These symptoms are an indication to take a blood test for thyroid hormones and TSH (tsh). You should not refuse blood tests for hormones in this condition, as this may lead to missing the onset of the development of a serious pathology in a severe form, the treatment of which will be extremely difficult and complex. The need for testing should always be determined by the doctor, not the patient.

Indications for TSH analysis

Biochemistry - a blood test for TSH hormones is prescribed for many reasons. The need to take a blood test arises in the following cases:

suspicions of hypothyroidism with a latent course;
amenorrhea;
female infertility in the normal state of the genital organs;
baldness;
frequent depression;
deterioration of muscle function (especially muscles of the limbs);
a significant decrease in body temperature without obvious reasons;
delayed sexual development;
mental retardation;
decreased libido;
impotence;
arrhythmia in the absence of pathology of the heart muscle;
fatigue.

If the doctor suspects the need for hormonal therapy, he prescribes a TSH test. After studying the test results, the specialist selects the optimal treatment for the patient.

Preparing for the test

Knowing what TSH is, it is very important to properly prepare to take TSH tests. Since the hormonal levels in the human body are influenced by many factors, if the recommendations are not followed, it will be impossible to understand what the result of the study says. The results of the analysis are interpreted based on the fact that the patient followed certain recommendations the previous day before taking blood. The doctor giving the referral will tell you how to take the test correctly. If this has not been done, information on how to properly donate blood for a TSH test can be obtained from the nurse collecting the material.

First of all, the level of the hormone in the blood is affected by food intake, and therefore, when preparing to take tests for hormones, you should stop eating food at least 12 hours in advance. Also, in order for the test to show TSH correctly, 5 days before the test they refuse foods that negatively affect the hormonal system, and therefore exclude fatty foods, alcohol, lemonade and fast food. If this is not done, then the values shown by the TSH test result will not correspond to the real picture and you will have to take the TSH test again.

For cigarette lovers, the relevant question is how long you should not smoke before donating blood for the TSH hormone. Ideally, of course, refuse bad habit a few days before the collection of the material, but if this is not possible, 4 hours before the procedure will be enough, which will be spent without a cigarette.

When an analysis is done, there are no restrictions on liquid, unless, of course, a person drinks only clean, still water. You can drink it in any volume and even immediately before taking a blood test. If the desire to eat before the procedure is irresistible, you are allowed to drink a cup of warm, weak green tea. In this quantity, it will not change the blood picture, but will eliminate the unpleasant feeling of hunger. This drink, but already strongly brewed, is recommended after blood sampling if you feel weak and dizzy after it.

When a person is preparing for an analysis, for a period of 5 days before it, it is necessary, if possible, to stop taking medications, since they can disrupt the picture, which means the unreliability of the results and, as a result, the incorrectness of further treatment. If you cannot give up medications, there is still a way to get a TSH test done correctly. In such a situation, the rules for taking a biochemical analysis establish the need to inform the doctor taking the blood what drugs and in what volume were taken and how long before the analysis, which means that the result will be determined taking into account possible errors using a special table. Most often this concerns adults taking life-saving medications.

Taking material for analysis from women deserves special attention. They are often interested in the question of how to donate blood during the menstrual cycle. This condition does not affect the TSH level, which allows analysis.

The test is taken in the morning, when hormonal levels have not yet been changed by physical activity and stress, from 8 am to 12 noon. Blood is taken from a vein. After the procedure, you can eat immediately.

Knowing how to take the test correctly, you can get the most accurate result, which will give the doctor all the necessary data for competent therapy.

Therefore, it is prescribed by an endocrinologist for any suspicion of dysfunction of this organ. The examination is indicated for people who experience the following symptoms: quick loss weight, tremors of the limbs, increased or decreased appetite. However, you should not try to decipher the results yourself; only the attending physician can make a final diagnosis.

What is a TSH blood test?

Thyrotropin analysis is a laboratory diagnostic procedure that determines the amount of an important substance in the body that regulates the activity of the thyroid gland, stimulating the production and. They are involved in the functions of the reproductive and digestive systems, heart and brain.

A test for the hormone thyrotropin is performed in combination with checking the concentration of thyroxine and triiodothyronine in the blood.

Preparing for analysis

Before donating blood, you should carefully prepare.

3 days before donating blood, avoid drinking alcohol, increased physical and emotional stress, overheating and hypothermia.

If possible, you should stop using medications, especially hormonal and iodine-containing ones.

Test for thyroid-stimulating hormone in the morning on an empty stomach; drinking a small amount of water is allowed. Avoid eating no later than 12 hours before the procedure. Compliance with the rules for preparing for blood donation increases the accuracy of the test results.

On what day should I take a TTG test?

Most women are interested in the question of what day of the menstrual cycle can they take the test. The level of the test hormone does not depend on the cycle, but doctors recommend undergoing this procedure on days 5-8.

How to donate blood for TSH?

The rules for submitting material for research will be as follows. Venous blood sampling is carried out from 8 to 11 am. Before this, the patient should sit quietly for half an hour. The material is obtained from the ulnar vein of either arm. The frequency of examinations depends on the nature of the pathological process and is determined by the attending physician.

An annual thyroid-stimulating hormone test is recommended for women who have entered menopause. Patients of reproductive age can undergo testing once every 3 years. Frequent blood donation is indicated for damage to the pituitary gland.

What does a TSH blood test show?

Independent interpretation of the results will not replace a full consultation with an endocrinologist, especially if the tests showed deviations from the norm. In such situations we're talking about about the possible presence of thyroid pathologies.

In organism:

newborns – 1.1-17 mU/l;
children of the first year of life – 0.4-7 mU/l;
adolescents 0.4-5 mU/l;
adults – 0.4-4 mU/l.

The level decreases as the body grows and develops. Only an endocrinologist can determine how much of the hormone should be contained in the patient’s blood, especially when it comes to older people.

When interpreting the tests, the doctor takes into account the patient’s age, weight and gender, the presence of chronic diseases, the treatment received, and the general condition of the body.

In the blood it is observed in mental and somatic pathologies: benign and malignant tumors of the pituitary gland, various types, syndrome of uncontrolled production of thyrotropin.

High TSH levels indicate the body's insensitivity to thyroid hormones and may indicate dysfunction of the adrenal glands, breast or lung cancer, or gestosis in pregnant women. The analysis can give such a result even after removal of the gallbladder, undergoing hemodialysis, in case of poisoning with heavy metal salts and increased physical activity.

Indicates the presence of the following pathologies: mental disorders, thyrotoxicosis of various origins, consequences of improper intake of hormones.

Damage to the pituitary gland, exhaustion of the body due to fasting and the use of certain medications lead to a decrease in the level of thyroid-stimulating hormone.

The article provides information about what TSH hormone tests are, in what cases they are prescribed, and what are the instructions for preparing for them. Reference values for patients are indicated of different ages and gender. 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 regulating the functioning of the thyroid gland. Thyrotropin is a glycoprotein whose molecular weight is approximately 28 kDa.

Its effects on the thyroid gland are multifaceted:

Initiation of cell growth of thyrocytes.
Stimulation of the production of thyroid hormones.
Activation of mitotic activity of gland cells.

Determining its content is one of the most important tests in diagnosing glandula thyreoidea dysfunction.

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, which circulate in the peripheral blood, drops. Consequently, the concentrations of TSH and thyroid hormones are inversely related.

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

Sleep/wake.
Presence of nonspecific stress.
Decrease in ambient temperature.

The rhythm of hormone production is disrupted if the subject is awake at night. During certain phases of pregnancy, TSH production drops and this is normal.

Factors affecting TSH concentration

If a person is forced to stay awake at night, the release of TSH is disrupted. Low levels of hormone production are also observed during pregnancy and breastfeeding, but this is the norm for such special conditions. The level of production of this biologically active substance can be influenced by a number of medications and pathologies of some organs associated with glandula thyreoidea.

In addition, heavy physical activity, severe stress, acute infectious pathologies and long-term low-calorie diets can lead to changes in thyrotropin levels.

Antibodies to TSH

Antibodies to the thyroid hormone TSH are a certain type of immunoglobulin, the action of which is directed against the precursors of the thyroid hormone. They are considered specific markers of autoimmune thyroid pathologies.

If there is any malfunction in the functioning of the immune system, antibodies to TSH, or more precisely to its receptors, are formed in the blood serum, which cause their death, due to which the synthesis of thyroid hormones becomes impossible, or, on the contrary, is carried out in excess quantities.

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;
heart rhythm disturbance;
convulsions;
weight loss;
muscle weakness;
temperature increase;
bone pain;
hair loss;
menstrual dysfunction in women;
erectile dysfunction in men.

In addition, with diffuse toxic goiter, a life-threatening complication may occur - thyrotoxic crisis.

Failures in the production of thyroid-stimulating hormone

The TSH concentration may change either upward or downward. These fluctuations can be caused by the condition of the pituitary gland, hypothalamus and/or thyroid gland.

Some combinations of diseases with levels of T3, T4 and TSH are shown in the table below:

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

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 unrelated to glandula thyreoidea, as well as medications used to treat them, can temporarily change the level of TSH in peripheral blood. As a rule, its level falls in the acute period and rises slightly during recovery.

In 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 collecting biological material for analysis, the TSH level will not change, since the normalization of thyrotropin levels occurs very slowly (it may take several weeks or even months of continuous use of medications ). The reason for this is hyperplasia of thyrotrophs, which develops against the background of chronic severe hypothyroidism.

Therefore, it makes sense to monitor replacement therapy, using a thyroid-stimulating hormone test as a guide, no less than one and a half months after the start of treatment, drug change or dosage change.

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 thyroxine, which causes a drop 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 stages indicates possible latent hypothyroidism, which can cause harm to the fetus.

Indications for TSH analysis

This study is prescribed for:

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

The referral is written by an endocrinologist, who, in most cases, evaluates the result.

Preparing for the study

To achieve maximum results from the analysis, it is important to prepare for it correctly.

Refusal to take hormonal medications or multivitamin complexes containing iodine (only after permission from the endocrinologist). If it is undesirable to interrupt the course of therapy, warn the laboratory technician that you are taking any medication constantly.
Avoid drinking alcohol 2-3 days before the planned examination.
A light dietary dinner the day before the blood draw, which should be no later than 19.00.
Testing on an empty stomach (you are only allowed to drink a little still water if you are thirsty) in the morning.
Avoid intense physical activity and stress immediately before going to the laboratory.

In addition, you will find answers to questions that interest many patients in the table below.

Note! The results of the examination may be negatively affected by previous surgical interventions and x-ray exposure. After these procedures, it is advisable to postpone the analysis of thyroid hormones for 2-3 months.

Table 1: Description of the TSH test:

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 TSH concentration, the collection 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.

Over the entire history of analysis, 3 generations of analyzers have been developed to determine the concentration of thyrotropin. The 1st generation is almost out of use these days, while the 2nd and 3rd generation are actively used by modern laboratories.

II generation of analyzers

It is based on ELISA (enzyme-linked immunosorbent assay) technology. The analyzers used in this case have a number of advantages:

Low price.
Small sizes.
Available domestic reagents.
Possibility of use without complex automated laboratory equipment.

But the second generation also has negative side, - 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 lower than when using next-generation analyzers.

III generation of analyzers

Here, another technology was taken as a basis - the immunochemiluminescent method. The TSH analysis carried out with its help has an error 500(!) times smaller than that of the 2nd generation - 0.01 µIU/ml. Therefore, it makes sense to apply for thyrotropin testing to laboratories that use third-generation analyzers.

Analysis transcript

The study result is read by an endocrinologist.

Reference values for 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, both in reference values and units of measurement, which can cause confusion in reading the results.

Elevated TSH

In rare cases, an increase or decrease in TSH value 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 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 therapy or violations that it allows. When a TSH test is received, what should be done, if its level is elevated - treatment, otherwise the risk of hypothyroidism is high.

Low TSH

Low TSH values can result from:

hyperfunction of the thyroid gland;
damage to the pituitary gland that prevents the production of TSH;
taking antithyroid drugs in insufficient dosage;
overdose of drugs in the treatment of hypothyroidism;
third trimester of pregnancy.

If tests show 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 data obtained from the research results and their potential significance:

TSH	Free T4	Free or common T3	Probable Cause
high	normal	normal	Subclinical (hidden) hypothyroidism
high	short	low or normal	Hypothyroidism
short	normal	normal	Subclinical (latent) hyperthyroidism
short	high or normal	high or normal	Hyperthyroidism
short	low or normal	low or normal	Secondary (pituitary) hypothyroidism
normal	high	high	Thyroid hormone resistance syndrome

In the thyroid gland, diseases often develop due to the formation of nodules in the tissues. It is possible to identify them at an early stage through a “happy” accident. It is unlikely that you will be able to feel a nodule (seal) slightly smaller than 1 cm in the thyroid gland with your own hands. There is no treatment as such, but regular examination by an endocrinologist is necessary.

The thyroid node is clearly visible using special equipment. If there is a rapid increase in neck volume, this may indicate a more serious or malignant disease.

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

Price of the procedure

Tests for thyrotropin levels are not carried out in all clinics, since the reagents are quite expensive, such tests are not carried out very 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 that still determines the concentration of TSH.

The price of the analysis depends on several inputs:

generations of analyzers used by a particular laboratory;
size and status settlement, where the establishment is located;
qualifications of laboratory complex maintenance personnel.

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, a test for TSH hormones can also cost different amounts - in residential areas it is cheaper, but in the center it is much more expensive.

Questions for the doctor

Elevated TSH in tests

Recently, in company with my mother (she has a goiter), I decided to get tested for my thyroid gland. I received the results: TSH – 8.2 mU/l, T3 and T4 are normal. What kind of analysis is TSH? What could his increase 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 thyroid function. An increase in its concentration can have a lot of reasons, but with normal T3 and T4 levels, it most likely indicates subclinical hypothyroidism.

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

Changes in thyrotropin in tests

Hello! I examined my thyroid gland for the first time after a miscarriage at 10 weeks. Then they diagnosed “autoimmune thyroiditis” (there were signs of inflammation on ultrasound + TSH – 9 mU/l) and prescribed Eutirox 50 mcg. Recently I was examined - TSH - 0.024. The doctor said that this was not enough and immediately stopped the hormones. I repeat the examination after 2 months, TSH is even lower – 0.009. What could this be connected with, since I don’t take hormones?

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

Laboratory diagnosis of hypothyroidism

Valentina, 46 years old: Hello! I recently took hormone tests, TSH was 18.2 µIU/ml, T4 7.3 pmol/l. A doctor I know said that the first one is just off the charts. What are the normal TSH levels in my case? So 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 is significantly higher than normal: 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 pregnancy with low TSH

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

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

TSH and pregnancy

Evgeniya, 28 years old: Hello. Two years ago I was diagnosed with hypothyroidism, I am seeing an endocrinologist, I take L-thyroxine at a dosage of 50 mcg per day. Now my husband and I are actively planning a pregnancy, I am undergoing a preventive examination. According to the results of tests for hormones, TSH is at the upper limit of normal, T3 and T4 are normal. The doctor insists on increasing the dose of hormones to 75 mg/day, linking this with the upcoming pregnancy. Is this justified?

Hello, Evgeniya! To answer your question in detail, you need to know many nuances, from the history of your disease to the dynamics of laboratory tests throughout last months. But in general, I agree with your attending physician: without increasing the dosage of L-thyroxine by early stages During pregnancy, you may develop subclinical and then manifest hypothyroidism.

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

Thyroid hormones regulate metabolism and activity nervous system, heart function, etc. For many complaints, doctors recommend starting an examination with thyroid hormones. The most commonly prescribed test is thyrotropin (TSH). This indicator is highly stable and accurate. TSH can be used as a screening, that is, it can be determined in groups of practically healthy people to identify hidden problems in the thyroid gland.

Hormone TSH

An interesting fact is that TSH is not a thyroid hormone at all. Based on its level, hypothyroidism and thyrotoxicosis can be diagnosed, and the effectiveness of treatment with thyreostatics and synthetic thyroid hormones can be monitored. But TSH itself is released into the blood from the endocrine cells of the anterior pituitary gland. This central endocrine gland sets the rhythm for the work of the peripheral glands. The pituitary gland also stimulates the functional activity of the thyroid gland. It is for this purpose that its cells produce a tropic hormone-stimulator of thyroid tissue - TSH.

TSH levels are affected by:

hypothalamic releasing factor (thyroid hormone-releasing hormone);
somatostatin;
thyroxine and triiodothyronine.

Thyroid hormone increases TSH production. Thyroid hormones (T4, T3) act on thyrotropin according to the principle of negative feedback. If there is too much T4 and T3, then TSH decreases. In the case when peripheral hormones are insufficient, thyrotropin, on the contrary, begins to increase.

TSH is synthesized and enters the blood in a special daily rhythm. At night, peak releases of thyrotropin into the blood are observed. TSH concentration reaches its maximum values 2-4 hours after midnight. In the early morning hours, TSH is also consistently high. Then its concentration begins to slowly decrease and reaches a minimum at 18 hours.

If a person is forced to stay awake at night (for example, during a shift work schedule), then a physiological increase in TSH levels is not observed. This ultimately affects the functioning of the thyroid gland and the body as a whole.

Action of thyrotropin:

enhances the growth of blood vessels in the thyroid gland;
increases iodine uptake from plasma;
stimulates the formation of thyroglobulin molecules;
increases the rate of transformation of thyroglobulin and the separation of T4 and T3 from it;
increases the synthesis of T4 and T3;
affects the breakdown of adipose tissue (lipolysis).

When should you take a TSH test?

Thyrotropin is tested if thyroid dysfunction is suspected. This hormone is also of interest when examining for pituitary adenoma. There are other clinical situations when TSH determination is necessary.

Indications for analysis:

search for latent hypothyroidism;
control of treatment with hormones for hypothyroidism (1-2 times annually);
control of treatment of thyrotoxicosis (according to indications, up to 1 time every 3 weeks);
delay intellectual development child;
delay physical development child;
delayed sexual development of the child;
the presence of diffuse, nodular or mixed goiter;
interruptions in the functioning of the heart (various rhythm disturbances);
myopathy;
persistent decrease in body temperature;
hair loss;
emotional suppression and depression;
male and female infertility;
menstrual irregularities;
decreased sex drive;
impotence;
high level of blood prolactin;
galactorrhea.

How to properly prepare for research

TSH is a fairly stable indicator. However, to get an accurate result, you need to properly prepare for the analysis.

take control tests for TSH at the same time of day;
come for examination on an empty stomach (at least 4 hours without food).

Desirable:

donate blood from 8 to 11 a.m.;
take your last meal 8-14 hours before blood sampling;
do not smoke on the day of the study before the analysis;
give up alcohol 3 days before the test;
avoid heavy physical activity and emotional stress for several days;
do not undergo tomography, x-rays, or ultrasound on the day of the examination before blood sampling.

Women do not need to schedule an examination for a specific day of the cycle. The TSH level changes little in different phases.

The concentration of the hormone is influenced by the intake of iodine from food and biological supplements. Also great importance is treated with thyreostatics and thyroid hormones.

You need to remember that:

TSH is taken no earlier than 6-8 weeks after adjusting the dose of levothyroxine;
TSH is taken no earlier than 21 days after adjusting the dose of thyreostatics;
The dose of potassium iodide is not changed for 3-4 weeks before the test.

In some cases, doctors give different recommendations. For example, it may be necessary to discontinue potassium iodide the night before the test or wait more than 8 weeks after the levothyroxine dose is adjusted. These recommendations are given by the attending physician. It is with him that you need to consult before the study.

Hormone standards

TSH levels change throughout life. In children of the first year of life it is relatively high, then the concentration of thyrotropin decreases. TSH increases slightly after 45-50 years. During pregnancy, its level fluctuates. Many patients experience a physiological decrease in TSH.

In adults, the TSH norm is on average from 0.4 to 4.0 mU/ml.

Lower rates:

in women planning to conceive;
in pregnant women;
in people after removal of a thyroid cancer.

A TSH greater than 4.0 mU/ml is acceptable for elderly and senile patients, as well as all people with pathology of the cardiovascular system.

Description

Determination method Chemiluminescent microparticle immunoassay

Material under study Blood serum

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A pituitary hormone that regulates the functions of the thyroid gland. One of the most important tests in the laboratory diagnosis of thyroid diseases. .

TSH is a glycoprotein with a molecular weight of about 28 kDa. Synthesized in the anterior lobe of the pituitary gland. Activates the production and secretion of thyroid hormones (thyroid hormones), initiates cell growth and mitotic activity of thyroid cells. Synthesis and secretion of TSH are stimulated by thyrotropin-releasing hormone of the hypothalamus in response to a decrease in the level of circulating thyroid hormones. The level of TSH is in an inverse logarithmic relationship with the concentration of T4: as the level of T4 increases, the production of TSH decreases; as the level of T4 decreases, the production of TSH compensatory increases, which helps maintain the concentration of thyroid hormones at the required height. TSH secretion is influenced by various neuronal mechanisms and changes during sleep, low temperature, and nonspecific stress. TSH is characterized by daily fluctuations in concentration: blood TSH reaches its highest values at 2-4 a.m., high levels in the blood remain until 6-8 a.m., and minimum TSH values occur at 5-6 p.m. The reference values for TSH levels given below are applicable for outpatients in the period from 8 to 18 hours. The normal rhythm of thyrotropin secretion is disrupted when awake at night.

With clinically pronounced primary hypothyroidism (i.e., damage at the level of the thyroid gland, which leads to a decrease in its function), there is a significant increase in TSH levels against the background low level thyroid hormones. Primary hyperthyroidism, in contrast, is associated with decreased or undetectable TSH levels and high thyroid hormone levels. Determination of TSH levels makes it possible to identify subclinical stages of thyroid diseases, when the concentration of thyroid hormones is still maintained by regulatory mechanisms within the reference values. Typically, when screening for thyroid function, TSH is used as the only test or in combination with the determination of free T4.

Taking thyroxine preparations on the eve of taking blood for testing does not affect the concentration of TSH. Normalization of TSH levels during replacement therapy for hypothyroidism with L-thyroxine drugs occurs slowly (over several weeks and months), since in chronic severe hypothyroidism hyperplasia of thyrotrophs develops. The paradoxical combination - a high level of TSH and a high level of free T4 - during this period is an artificially induced (iatrogenic) condition. It is advisable to carry out repeated studies of TSH levels in order to monitor therapy no earlier than 6 weeks after changing the dose or type of drug.

In secondary and tertiary hypothyroidism associated with pituitary dysfunction due to pathology of the pituitary gland and hypothalamus, significantly reduced levels of T3 and T4 are combined with normal or slightly increased levels of TSH, which in these cases has reduced biological activity. Rare clinical cases of secondary hyperthyroidism may be due to TSH-secreting tumors.

Severe diseases not associated with thyroid pathology can cause a temporary change in TSH concentration. The cause may be the use of medications or the consequences of the disease itself. Typically, there is a decrease in TSH levels during the acute phase of the disease and a slight increase in levels during recovery. If necessary, in such cases, it is advisable to focus on the extended reference range of TSH (0.02-10 mU/l) and use a set of tests for TSH and T4 (or free T4).

Physiological changes in TSH concentrations are observed during pregnancy. High concentrations of human chorionic gonadotropin, which has a certain structural similarity to TSH, can have a stimulating effect on the synthesis of thyroid hormones. In the first trimester of pregnancy, a temporary increase in T4 levels and a decrease in TSH levels are observed. During the second and third trimesters, TSH levels return to normal. An elevated TSH level in early pregnancy may indicate latent maternal hypothyroidism, which is potentially dangerous for the development of the fetus.

Limits of determination: 0.0083 mU/l-100 mU/l

Preparation

It is preferable to take blood in the morning on an empty stomach, after 8-14 hours of overnight fasting (you can drink water), or 4 hours after a light meal during the day.

Recent exposure to the thyroid gland, including surgery, radiation therapy, drug therapy (including thyroid medications, iodine-containing medications), and ultrasound may affect the test result.

The conditions and time of the study are determined by the attending physician.

Indications for use

Diagnosis of subclinical stages of primary hypo- and hyperthyroidism. Conditions associated with delayed mental and sexual development in children, cardiac arrhythmias, myopathy, idiopathic hypothermia, depression, alopecia, infertility, amenorrhea, impotence and decreased libido, hyperprolactinemia.
Monitoring replacement therapy for primary hypothyroidism.
Screening of pregnant women in the first trimester to identify hidden hypothyroidism, potentially dangerous to the fetus.
Monitoring the condition in case of detected hypothyroidism (lifelong 1-2 times/year).
Monitoring the condition of detected diffuse toxic goiter (for 1.5-2 years, 1-3 times/month).

Interpretation of results

Interpretation of research results contains information for the attending physician and is not a diagnosis. The information in this section should not be used for self-diagnosis or self-treatment. The doctor makes an accurate diagnosis using both the results of this examination and the necessary information from other sources: medical history, results of other examinations, etc.

Units of measurement in the Independent Laboratory INVITRO: honey/l.

Alternative units: µU/ml = honey/l.

Unit conversion: µU/ml = honey/l.

Reference values

Approximate limits during pregnancy:

1st trimester: 0.1-2.5 mU/l
2nd trimester: 0.2-3.0 mU/l
3rd trimester: 0.3-3.0 mU/l

Increasing values:

Primary hypothyroidism (autoimmune thyroiditis; iodine deficiency, hereditary defects in hormone synthesis, congenital abnormalities of the thyroid gland, consequences of surgical removal of thyroid tissue).
Subclinical hypothyroidism.
Subacute thyroiditis (recovery phase).
Ectopic secretion of TSH (lung, breast tumors).
TSH-secreting pituitary adenoma (rare).
Severe somatic diseases (recovery phase).
Thyroid hormone resistance syndrome.
Thyroid cancer.
The use of drugs such as amiodarone, beta-blockers (atenolol, metoprolol, propranolol), radiocontrast agents, neuroleptics (phenothiazine derivatives, aminoglutethimide), clomiphene, antiemetics (motilium, metoclopramide), anticonvulsants (phenytoin, carbamazepine), furosemide, iodine-containing preparations (for example, solutions for skin sterilization), lithium salts.

Reducing values:

Primary hyperthyroidism (diffuse toxic goiter, toxic multinodular goiter, toxic adenoma, autonomously functioning thyroid nodes).
Subclinical hyperthyroidism.
Transient thyrotoxicosis in autoimmune thyroiditis.
Iatrogenic or factitious hyperthyroidism (including possible self-prescription of T4).
Hyperthyroidism in pregnancy.
Secondary (pituitary) hypothyroidism, including due to injury to the pituitary gland.
Stress, starvation.
Severe non-thyroid diseases (acute stage).
Hypothalamic-pituitary insufficiency.
Pituitary tumor.
Itsenko-Cushing syndrome.
Taking medications such as corticosteroids, dopamine, thyroxine, triiodothyronine, amiodarone, cytostatics, beta-adrenergic agonists (dobutamine, dopexamine), somatostatin, octreotide, nifedipine, drugs for the treatment of hyperprolactinemia (metergoline, peribedil, bromocriptine), heparin, acetylsalicylic acid preparations.