Analysis of thyroid hormones (normal levels of TSH and T4 hormones)

What thyroid hormones are tested?

At the moment, the Internet is replete with materials on medical topics. In particular, there are articles on the topic of a blood test to assess the level of thyroid hormone production. As a rule, these texts are not written by doctors, and therefore are illiterate and contain a lot of factual errors. Such materials will not answer questions, but will only confuse the reader even more.

Among the thyroid hormones, ignorant authors include, in addition to triiodothyronine (T3) and thyroxine (T4), also TSH and TPO. But this is fundamentally wrong.

The first two hormones are classified as thyroid hormones quite rightly. They are actually synthesized by the thyroid gland. While TSH is a non-specific hormone, the synthesis of which is carried out by another endocrine organ – the pituitary gland.

The pituitary gland is a small gland located in the brain. The main function of the pituitary gland is to regulate the functioning of the entire endocrine system with the help of the release of active substances (it must be said that it secretes a number of active substances, their number is determined by dozens).

Thus, TSH (the so-called thyroid-stimulating hormone) is the “signal” hormone of the pituitary gland. Thanks to its effect, the thyroid gland increases the intensity of work and releases more active substances.

TPO also cannot be classified as a thyroid hormone. This substance is not a hormone at all, but is an antibody. The immune system secretes it to destroy iodine-containing substances. However, all four of the above substances must be considered together, since they are closely related to each other and form the mechanism of the thyroid gland.

Thyroxine (tetraiodothyronine T4). One of the two main thyroid hormones. It makes up the majority of all compounds synthesized by the thyroid gland (up to 90%).

Triiodothyronine (T3). It is another thyroid hormone. Its activity exceeds the activity of T4 by 1000%. The composition of T3 includes three iodine atoms, not 4, so the chemical activity of the hormone increases significantly. Many consider triiodothyronine to be the main thyroid hormone, and T4 as the “raw material” for its production. T3 is synthesized from T4 by acting on the 4-atom hormone with selenium-containing enzymes.

Both T4 and TXNUMX are specific thyroid hormones, that is, they belong to the thyroid hormones. Their synthesis is necessary for the normal functioning of the autonomic and nervous systems, as well as for the basic metabolism, due to which the functioning of autonomous energy-consuming processes occurs: contraction of the heart muscle, transmission of nerve signals, etc.

Specific hormones can exist both in a free and in a bound state. For this reason, several graphs are often distinguished in the results of laboratory tests: free T3-hormone or free T4-hormone. May also be referred to as FT3 (Free T3) or FT4 (Free T4). Most of the thyroid substances are in a state associated with protein compounds. When hormones are released into the blood, they combine with a special TSH protein (thyroid-binding globulin) and are transported to the necessary organs and systems. As soon as the transport is completed, the thyroid hormones return to the free form.

Free hormone has activity, therefore, to assess the functioning of the thyroid gland, the study of this indicator is necessary and most informative.

TSH – This is a pituitary hormone that affects the functioning of the thyroid gland by acting on the receptors of thyrocyte cells.

Such an impact can cause the following consequences:

• Increasing the intensity of the synthesis of thyroid hormones (due to the fact that thyroid cells begin to work more actively);

• Thyroid tissue growth. As tissues grow, diffuse changes in the organ increase.

Antibodies

The next most important indicator is antibodies. An assessment of the amount of antibodies to iodine-containing compounds is necessary for a correct diagnosis.

There are three types of antibodies:

• Proteins to TPO (thyreoperoxidase);

• Proteins to TG (thyroglobulin);

• Proteins to rTTH (TSH receptor).

In the results of laboratory studies, abbreviated forms of the names of substances are most often indicated. AT is an antibody. TG, rTTG, TPO.

Antibodies to thyroperoxidase

TPO is one of the main enzymes directly involved in the synthesis of thyroid hormones. Depending on the degree of deviation of the result from the normal, an increased concentration of these antibodies may not manifest itself in any way, or lead to hypothyroidism (a decrease in the level of thyroid hormone production). Elevations are relatively common, affecting about 10% of women and half as many men (5%) globally.

Since the concentration of iodine-containing substances in the thyroid gland is maximum, thyroperoxidase disrupts the work of thyrocyte cells. As a result, the amount of thyroid hormone produced decreases. It is impossible to unequivocally call the excess of the indicator a marker of the disease, however, studies and statistics show that an increase in the content of TPO leads to hypothyroid diseases of the thyroid gland about 5 times more often than in similar cases when the level of hormones is normal.

A blood test for the presence of this substance is carried out in order to detect diffuse toxic goiter of the thyroid gland and autoimmune diseases.

Antibodies to thyroglobulin

Exceeding the level of antibodies to thyroglobulin is much less common than a similar result for antibodies to thyroperoxidase. According to statistics, the number of people with a positive deviation from the norm is about 5% of women and about 3% of men.

The indicator is quite variable and can indicate the presence of two types of diseases:

• DTG of the thyroid gland or Hashimoto’s autoimmune thyroiditis;

• Oncological disease of the thyroid gland.

In the second case, they speak of two forms of cancer: follicular or papillary, since it is with these types of tumors that an increased production of triglycerides occurs. Thyroglobulin is produced only by thyroid cells or malignant tumor cells. If an excess of the norm is detected, both the patient and the attending physician should be wary. TG simultaneously acts as a tumor marker.

After the operation to remove the tumor along with the affected thyroid gland, the thyroglobulin level should drop to the minimum levels (down to zero). If this does not happen, the reason lies in the recurrence of cancer.

It should be borne in mind that with an increased indicator of antibodies to TG, the result may be incorrect. Antibodies create a single structure with the iodine-containing protein TG and are so tightly bound that it is impossible to distinguish between the protein secreted by lymphocytes and thyroglobulin itself in a laboratory study. To assess the level of TG, it is necessary to conduct an independent analysis.

You also need to keep in mind that an excess of thyroglobulin levels is far from always an indicator of oncology. It is simply pointless to analyze the concentration of TG in the blood in patients with an unremoved thyroid gland. An excess of TG can be considered a tumor marker only if the gland has been removed.

In patients with other changes in the organ, the TG indicator may differ from the norm for many reasons: diffuse pathological transformations of the endocrine organ, in which the volume of the organ tissue grows, nodular formations, etc. If a relatively healthy patient is prescribed a blood test for thyroglobulin, this means only one thing: the clinic conducting the analysis wants to cash in on the person’s ignorance and includes in the list of laboratory tests what is not needed.

To identify the presence of cancer in patients whose thyroid gland has not been removed, it is advisable to prescribe a blood test for calcitonin content. This is a really important marker of oncology. It allows you to identify the medullary form of thyroid cancer. C-cell carcinoma is an extremely dangerous and practically incurable disease in the last stages. Neither chemotherapy nor radiation therapy gives any adequate results. The only way to cure this thyroid tumor is to have surgery on time. For this, it is necessary to detect the disease in time.

As a rule, in patients with diffuse changes in the organ, the likelihood of developing medullary cancer is minimal. If there are nodular and diffuse-nodular changes in the thyroid gland, the appointment of a blood test for calcitonin is mandatory. The study of venous blood should be carried out in conjunction with a fine needle biopsy.

Antibodies to rTTG

An analysis for the presence of antibodies to thyroid-stimulating hormone receptors is prescribed for patients with confirmed thyroid diseases (for example, with diffuse toxic thyroid goiter).

The study of venous blood is carried out against the background of conservative therapy with drugs that reduce the level of production of specific active substances. As studies show, the outcome of the disease often depends on the level of decrease in antibodies to rTSH. If therapy does not bring the desired effect, and the degree of antibody concentration does not decrease, this means an unfavorable course of the disease. In this case, the patient should be prescribed surgical treatment.

However, exceeding the indicator in itself is not an absolute indication for surgical intervention. When making a decision, the doctor must proceed from a system of factors: the general course of the disease, the degree of nodular and diffuse changes, the size of the goiter, etc.

Thus, a person with suspected thyroid pathology or with a confirmed organ disease needs to conduct a venous blood test for the following indicators:

• T3 (triiodothyronine);

• T4 (tetraiodothyronine or thyroxine);

• TSH;

• Antibodies to thyroglobulin;

• Antibodies to thyroperoxidase.

Whether or not to investigate other indicators is decided by the endocrinologist, based on the patient’s history.

Why does the thyroid gland produce hormones?

The thyroid gland produces hormones to create the basis necessary for the normal functioning of all systems and organs. Thanks to it, a stable energy metabolism in the body and the work of the autonomic nervous system are ensured.

Figuratively, the body can be imagined as a multi-storey building powered by coal, and the functioning of the thyroid gland can be imagined as the work of a coal-fired boiler plant. Coal in this case is the thyroid hormones themselves.

If you add too much coal to the boiler room, it becomes hot in all rooms. People who work in the building suffer from too high a temperature, sweat, faint, etc. If too little coal is added, the heating effect will not be enough, the rooms will freeze. People will begin to suffer already about the cold, dress warmer and try to hide from the low temperature.

Obviously, in both cases, there is no normal mode of operation, and everyone will only think about how to hide from adverse conditions.

In the given example, human workers represent all other hormones (pituitary, adrenal, pancreas, etc.) produced by the human body, as well as organs and systems.

In the normal state, the role of the thyroid gland is almost imperceptible, but as soon as failures and violations begin, serious consequences arise. The thyroid gland provides the necessary base for the minimally efficient and stable functioning of the whole organism.

Depending on the type and form of pathological changes in the thyroid gland, two main cases are possible:

• Too many hormones are synthesized (excess);

• Specific hormones are not enough for the normal functioning of the body (deficiency).

Excess thyroid hormones (thyroid hormones)

By analyzing venous blood, it is quite easy to determine the excess amount of thyroid hormones. This situation is called “hyperthyroidism”, and its consequences for the body are called thyrotoxicosis.

With an excess of thyroid hormones, a number of symptoms are observed:

• Hyperthermia. In other words, an increase in body temperature. Persistent and periodic, up to subfebrile condition (marks at 37,1 – 37,7);

• Strengthening mental and motor activity. The person becomes aggressive, nervous and overly excitable;

• Change in body weight. The weight of the body steadily falls, despite the fact that the patient has a brutal appetite and consumes more food;

• Tremor. There is a trembling of the limbs (fingers and the hands themselves are shaking), and sometimes the head.

At later stages or with a significant deviation of the level of thyroid hormones from the norm, more formidable manifestations of hyperthyroidism are observed:

• Cardiac disorders. Vascular hypertonicity, increased pressure and persistent tachycardia even in the absence of physical activity;

• Disorders of the nervous system. A person suffers from intelligence, concentration and memory;

• Disorders of the functioning of the digestive tract. There are frequent constipation or diarrhea, “indigestion”, upset stomach and intestines.

With hyperthyroidism, systemic disorders in the work of all organs are noted.

An indicator of hyperthyroidism is an elevated level of triiodothyronine and tetraiodothyroxine (T3 and T4). At the same time, the level of the pituitary hormone TSH decreases sharply. If an increased concentration of free thyroid hormones is detected in the blood, even to a small extent, the patient is prescribed special treatment in order to normalize their content.

If the excess is significant, and conservative treatment does not give the necessary results, surgical intervention is prescribed.

Lack of thyroid hormones

A condition in which the level of specific substances of the thyroid gland in the blood is below the indicated minimum is called hypothyroidism.

Hypothyroidism is characterized by the following manifestations:

• Hypothermia. Decrease in body temperature to 35,5 ° C. The temperature does not return to normal even with physical activity;

• Pressure drop. Blood pressure falls below normal levels (up to 90-85 / 60-50). There is hypotension;

• Edema. Fluid is excreted from the body at a very slow rate. The normal functioning of the excretory system is disturbed, the kidneys cope worse. Serious swelling of the limbs and face occurs;

• Insomnia. At night, the patient cannot sleep, and during the day he feels weak, lethargic, and weak. The biological rhythm goes astray;

• Increase in body weight. Often hypothyroidism is accompanied by obesity. The reason for this is a decrease in the metabolic rate;

• Insufficient efficiency of other endocrine glands. Contributes to the occurrence of adverse effects. A decrease in the level of production and exposure of sex hormones entails the extinction of libido and sexual dysfunction, and failures of the monthly cycle. The weakening of the secretion of digestive hormones contributes to unstable blood sugar levels, malfunctions of the digestive system. A decrease in the production of pituitary substances affects the functioning of the nervous system and the body as a whole;

• Deterioration of the skin and nails. The skin becomes dry and flabby, the nails become brittle, the hair falls out.

With a decrease in the level of hormones to critical levels, there is also a deterioration in the work of the heart (bradycardia, etc.). A venous blood test reveals a reduced level of thyroid substances. Simultaneously with the analysis for hormones, an analysis for antibodies to thyroperoxidase (TPO) should also be carried out to identify the cause of dysfunction. The source may be an autoimmune disease.

At the same time, both too much and not enough thyroid hormones nullify the reproductive function of the human body. Thyroid problems are one of the main causes of pregnancy difficulties. Women, both already pregnant and planning motherhood, also need to pay attention to the TSH indicator.

A serious problem is hormonal dysfunction in children and adolescents. If at an early and transitional age there is an excess or deficiency of thyroid hormones, there is a risk of mental retardation due to underdevelopment of the brain or problems with the nervous system.

Thus, the active substances of the thyroid gland, for all their invisibility, play a major role in the functioning of the body and the normal life of a person. Deviation in the level of thyrotropic active substances leads to severe systemic disorders that significantly reduce the quality of life.

What tests for thyroid hormones are taken in various cases?

if the endocrinologist recommended taking hormonal tests, but did not specify which indicators are required, it is important to find out exactly. If you have a clear understanding, the result will be as informative as possible, and you will not have to pay extra money for unnecessary tests.

Primary examination of the patient

If a patient visits an endocrinologist for the first time with complaints or for the sake of a preventive examination, it is necessary to investigate the following indicators:

• TSH (thyroid-stimulating hormone);

• T4 St. (free tetraiodothyroxine);

• T3 St. (free triiodothyronine);

• AT to thyroperoxidase (TPO).

This list will be enough to assess the general condition of the thyroid gland.

Suspicion of elevated hormone levels

If the patient has signs characteristic of an excess of thyroid hormones (hyperthermia, etc.), hyperthyroidism (thyrotoxicosis) must be ruled out.

In this case, the list of indicators for analysis will look like this:

• TSH (thyroid-stimulating hormone);

• T4 St. (free tetraiodothyroxine);

• T3 St. (free triiodothyronine);

• AT to thyroperoxidase (TPO);

• AT to TSH receptors (rTTH).

The latter indicator may most clearly indicate the presence of hyperthyroidism.

To monitor the effectiveness of treatment with thyroid drugs, the following are examined:

• T4 free;

• The CIA.

Analysis of other indicators is not required, since the figures remain the same during specific treatment or their dynamics is not of interest.

In the presence of nodular changes in the thyroid gland

If nodules are present in the thyroid gland, the initial blood test should include determination of the levels of the following substances:

• TSH (thyroid-stimulating hormone);

• T4 St. (free tetraiodothyroxine);

• T3 St. (free triiodothyronine);

• AT to thyroperoxidase (TPO);

• Calcitonin (tumor marker).

The latter indicator allows you to accurately determine the oncological diseases characteristic of the nodular form of goiter in the early stages.

In pregnancy

During pregnancy, the following are examined:

• TSH (thyroid-stimulating hormone);

• T4 St. (free tetraiodothyroxine);

• T3 St. (free triiodothyronine);

• AT to thyroperoxidase (TPO).

It is important to keep in mind that in pregnant women, the level of TSH hormone is often below the designated standard. This does not indicate the presence of diseases or pathological processes.

If an operation was performed to eliminate a papillary or follicular tumor of the thyroid gland

It is necessary to make sure that the hormonal level and the level of specific proteins are normal in order to exclude the recurrence of cancer.

Researched:

• TSH (thyroid-stimulating hormone);

• T4 St. (free tetraiodothyroxine);

• AT to thyroglobulin;

• thyroglobulin protein.

If surgery was performed to resect a medullary tumor

After such an operation, the following are examined:

• TSH (thyroid-stimulating hormone);

• T4 St. (free tetraiodothyroxine);

• Oncomarker calcitonin;

• CEA cancer specific antigen.

Tips

When deciding whether to take tests for the concentration of thyroid hormones in the blood, you need to follow a small list of rules. They will increase information content and avoid unnecessary cash spending:

• The concentration of antibodies to thyroperoxidase is examined once. Repeated blood donation to determine this indicator will not bring any information, since changes in the numerical value do not affect the dynamics of the course of the disease. A competent endocrinologist with this sign does not recommend taking such an analysis twice;

• It is not possible to study free and bound thyroid hormones in the same assay. The result for both those and other indicators will be blurry. If you are strongly recommended such a comprehensive analysis, it is simply a scam to increase your revenue;

• Patients with non-operated thyroid cancer should not be tested for thyroglobulin. This protein is examined only after removal of the thyroid gland and is a tumor marker of relapse. Even in a relatively healthy person, the indicator of this protein can exceed the norm. It doesn’t say anything. If a doctor or laboratory insists on including thyroglobulin in the analysis, this is a deceptive maneuver to extract money;

• If the patient does not have a suspicion of hyperthyroidism, it is not worth examining antibodies to a thyroid-stimulating substance. This analysis costs a lot of money and should be taken strictly according to the testimony of a competent specialist in order to exclude thyrotoxicosis or assess the dynamics of therapy with confirmed thyroid hyperfunction;

• Calcitonin is tested once. If no new nodes have appeared in the patient since the last check of the level of calcitonin in the blood, it is pointless to take this analysis. The same applies to the operation performed to remove the oncological neoplasm. Only these two cases are grounds for re-testing for calcitonin in order to exclude the appearance of tumors and relapse.

Norms of thyroid hormones in women

It should be noted that the uniform norms of hormones are long gone. Now the norm is determined depending on the type of apparatus on which the blood is examined, and the type of reagents used. The “reference” indicators are taken to be the figures fixed in international documents and agreements. Therefore, we can still talk about approximate numbers.

The norms of specific thyroid hormones and the pituitary hormone TSH are universal for both women and men. They are characterized by the same numbers.

Triiodothyronine (T3 hormone) in a free state

The study of this substance is associated with a number of technological difficulties and requires increased skill and attention from the personnel. If the technology is violated, the indicator may be unreasonably high. If there is doubt about the correctness of the result, the patient is assigned an analysis of the associated hormone (total T3).

The norm in modern clinics and laboratories is from 2,6 to 5,7 petamol / liter. Errors in the T3 study are very common.

The analysis is given, as a general rule, once. Re-examination is required in a number of cases:

• If the level of triiodothyronine exceeds the norm, and thyroid-stimulating hormone is within the normal range;

• If the level of triiodothyronine is below normal, and thyroid-stimulating hormone is within normal limits;

• If the level of triiodothyronine is below normal, and tetraiodothyronine is within normal limits.

Tetraiodothyronine (T4 hormone) in a free state

When analyzed in modern laboratories, its norm is in the range of 9,0-19,0 petamol / liter. In different institutions, slight changes in the upper limit are possible up to 3,0 units, but no more.

There are also many errors in this analysis. If the description of the laboratory study simultaneously contains a low level of tetraiodothyroxine, and the thyroid-stimulating hormone is normal, or vice versa, then the analysis is most likely carried out with violations. So the result is inaccurate. In this case, it is recommended to undergo the study again in another institution.

The norm of thyroid-stimulating hormone (TSH)

It has a normalized value on a global scale. Ranges from 0,39 to 3,99 micro-international units per milliliter. If the latest generation devices are used, the upper limit is increased by 1 unit.

When using the outdated ELISA method, the range in the description will be much lower (from 0,26 to 3,45). A high error, up to half a unit, is allowed, so it is better to retake the analysis in a modern clinic, moreover, at the same price.

Analysis for calcitonin

The norm of this substance is not strictly established. Each institution has its own. When carrying out the analysis, great accuracy is required, since even a small value, within half a unit, can indicate the initial and even advanced stage of the formation of a malignant tumor.

It is most reasonable to contact special endocrinological centers for stimulated analysis. With it, a calcium salt solution is injected intravenously, and after that, after a certain time interval, the value of the concentration of calcitonin in the blood is estimated.

Analysis for antibodies to thyroperoxidase

There is no strict norm established by international agreements or documents. The upper and lower limits vary from clinic to clinic. The study description sheet, the form of which is accepted by the laboratory, will define the range. It should be taken into account when evaluating the norm.

The most common standards are from 0 to 19-20 units or up to 120. This variation is due to the difference in devices and approaches to the study.

With a general primary interpretation (by the patient himself), several features should be borne in mind:

• The degree of excess of the concentration of antibodies in the venous blood does not play a role. To assess the state of the endocrine system, the very fact that the indicator goes beyond the upper bar is important. You should not pay special attention and panic, even if the result is exceeded a thousand times;

• A result that is within the range established by the laboratory is always considered normal. Various indicators, whether they are near the lower or upper limit, are absolutely equivalent. Even if the described result is only one less than the upper bar, this means that the indicator is normal. It is necessary to take into account this fact and not be afraid of a significant concentration if it fits into the normal range of numbers.

The degree of concentration of antibodies to thyroglobulin

In laboratories equipped with the latest generation of equipment, this indicator ranges from zero to 4,1 or 65 units.

There can be two reasons for the excess of antibodies to TG:

• The presence of a rare autoimmune disease (autoimmune Hashimoto’s thyroiditis);

• The presence of thyroid cancer (papillary or follicular cancer).

In both cases, to confirm the diagnosis, it is necessary to conduct a complex of other studies. So, to confirm Hashimoto’s thyroiditis, you need to evaluate the concentration of thyroid hormones and conduct functional studies. The diagnosis of thyroid cancer requires a fine-needle biopsy of the neoplasm.

Not always, even in patients with oncology, this figure is exceeded. Their number is not more than 30%. In other cancer patients, antibodies to thyroglobulin are normal. The reason for this is still not fully understood.

You should also not compare the results obtained by patients in different laboratories. They are not equivalent to each other and cannot be recalculated by the method of proportions, since there is a fundamental difference in technology and approach to research. It is especially important to know this for people who have undergone surgery to remove a malignant tumor of the thyroid gland.

Repeated blood donation for such patients helps to detect recurrence of the disease. Therefore, it is advisable to follow one rule: it is best to take an analysis for the concentration of antibodies to TG in the same laboratory where it was carried out the previous time.

How can a thyroid disease be detected by a blood test for hormones?

Tables of indicators of thyroid hormones

T3 hormone (triiodothyronine) total

TK hormone (triiodothyronine) free

T4 hormone (tetraiodothyroxine) total

T4 hormone (tetraiodothyroxine) free

TSH hormone (thyroid-stimulating hormone)

Interpretation of TSH level:

• Less than 0,1 μIU / ml – thyrotoxicosis (suppressed TSH)

• From 0,1 to 0,4 μIU / ml – probable thyrotoxicosis (low TSH)

• 2,5 to 4 µIU/mL is a high-normal TSH level

• 0,4 to 2,5 µIU/mL is low-normal TSH

• From 4,0 to 10,0 μIU/ml — subclinical hypothyroidism

• Over 10,0 μIU / ml – overt hypothyroidism

Other hormones

How to take a blood test for thyroid hormones correctly?

Often, patients who are about to donate blood for thyroid hormones turn to the Internet for help. There they expect to find general recommendations on how to prepare for the study, and how the sampling procedure itself takes place.

However, the network is replete with materials of extremely dubious content. Even with a cursory review, a knowledgeable physician will determine the inconsistency of most of the recommendations. The matter is aggravated by the wide circulation of such “articles”, since the sites copy materials from each other, only slightly altering the words, but leaving the essence.

Such recommendations should be avoided. Only in this case the analysis will be highly informative.

For example, it is often recommended to stop taking thyroid drugs a month before the test, and iodine-containing drugs a week before the test. Such information is fundamentally wrong, but an unknowing person will take it at face value.

In fact, the patient needs to know and follow a number of simple rules:

• The level of all thyroid and related hormones does not depend on the diet in any way. The analysis can be taken both before and after eating. The concentration of these substances in the blood is stable;

• Hormonal tests can be taken at any time of the day. Although the concentration of thyroid-stimulating hormone varies depending on the time of day, the fluctuations in the indicator are so small that the morning and evening difference does not play a significant role;

• Cancellation of hormonal drugs can be hazardous to health and reduce the effectiveness of treatment. In many cases, it is against the background of conservative therapy that an analysis is carried out, the purpose of which is to determine the effectiveness of treatment and track the dynamics of the process. The only recommendation is not to take medication on the day of the study;

• Iodine-containing drugs do not require cancellation at all. Their intake cannot affect the concentration of hormones, because the basis of any iodine-containing drug is the salt of this element. The transformation of the original substance is carried out by the thyroid gland, which will not start to work more actively or worse from taking iodine;

• During the menstrual cycle, the background of sex hormones changes, and not specific substances of the thyroid gland or pituitary hormones. No specific day of the cycle, including the period of menstruation, is not suitable for taking a blood test for the level of thyroid hormones, and also does not require special correction of the results.

Deciphering the results of tests for thyroid hormones

Deciphering the indicators obtained in the laboratory without the help of a specialist is a meaningless and thankless task. Only a doctor can correctly and competently interpret the results of research. Independent actions in this direction lead patients to incorrect conclusions.

In general, we can talk about some of the most common formulations and typical results. Indicators of the pituitary hormone TSH and specific thyroid-stimulating hormones must be interpreted systematically.

If the TSH hormone is above normal

This almost always means hypothyroidism (decreased thyroid function). As soon as the gland ceases to produce the level of active substances necessary for the normal functioning of the body, the pituitary gland secretes the stimulating TSH hormone.

There may be a situation in which T4 remains normal, then we are talking about a latent form of hypothyroidism.

In both cases, the thyroid gland works at its limit. However, if at the same time T4 is normal, the thyroid gland is in a euthyroid status, which can develop into more formidable diseases.

With an increase in the level of TSH in a patient, the following clinical manifestations are observed:

• Decreased psychomotor activity. The person looks lethargic and inhibited;

• Sleep problems (constantly want to sleep, no matter how long a person rests);

• Fragility of bones, nails and hair;

• Weakening of muscle tone.

With euthyroid status, specialized therapy is not prescribed. All assistance to the patient comes down to constant monitoring of the development of the process. If it stops, no further action is required. If the level of T4 synthesis is below normal, replacement treatment with synthetic thyroid hormones is prescribed until the condition normalizes (from 7 months to a year).

This picture of an erroneous result of the analysis is observed most often in people with existing or just preparing problems with the thyroid gland:

• If TSH is within the established normal range, and tetraiodothyronine is below normal. With almost one hundred percent probability, there is a research error. In 1% of cases, we can talk about Hashimoto’s autoimmune thyroiditis or about exceeding the dosage of drugs for the treatment of diffuse toxic goiter;

• If TSH is within the allowable value, and triiodothyronine (T3) is below normal – a laboratory error;

• TSH is normal, T4 is also within the acceptable range, and triiodothyronine below the established level is a laboratory error;

• TSH is within the normal range, and thyroid hormones are above it – a laboratory error. This is simply impossible, since there are no objective reasons for the intensification of synthesis (there is no signal from the pituitary gland).

Otherwise, if the thyroid-stimulating hormone is above the established norm, there is a situation of hyperthyroidism (thyrotoxicosis). If TSH deviates downward from the norm, and thyroxine is higher, we are talking about explicit hyperthyroidism. If specific hormones are within the limits of acceptable values, this is hyperthyroidism in a latent form. In all these cases, immediate medical attention is required.

The only exception is pregnant women. During pregnancy, the level of thyroid-stimulating hormone may fall below the established mark. This is part of a natural physiological process that does not require close attention and treatment.

What is the difference between the results of the analysis for free thyroid-stimulating hormone T4 during pregnancy?

When it comes to endocrinological examination of a pregnant woman, the doctor should be especially careful. The hormonal background of the expectant mother changes significantly. This applies not only to sex, but also to pituitary and thyroid hormones.

In the process of bearing a fetus, the level of thyroid-stimulating hormone, as a rule, decreases. The essence of this phenomenon is as follows: a special organ, the placenta, develops within the uterus. It is able to produce a specific active substance hCG (human chorionic gonadotropin). Its mechanism of action is similar to that of thyroid-stimulating hormone. It also stimulates more intensive production of thyroid active substances. Just for this reason, the synthesis of TSH falls. If the intensity of production of the pituitary active substance remains at the same level, the thyroid gland will release an excessive amount of thyroid hormones into the blood, hyperthyroidism will occur. For this reason, when assessing the degree of concentration of thyroid-stimulating hormone in the venous blood of a pregnant woman, a decrease in the level of TSH should be taken as the norm.

During the period of gestation, this hormone is in an unstable state, and its synthesis depends on the intensity of hCG production. In this regard, the level of free tetraiodothyroxine (T4 hormone) becomes a particularly important indicator. It is for him that it is necessary to determine the presence of pathological processes with the thyroid gland in pregnant women.

If thyroxine is outside the upper limit, but slightly, this can be considered as a variant of the norm. But the same may indicate the onset of thyroid disease. For clarification, it is necessary to conduct a complex of additional examinations.

In the event that the level of T4 is significantly exceeded, and against this background there is an increase in the content of triiodothyronine in the blood (may be separately or both at once), treatment should be started immediately and the hormones should be brought back to normal.

It makes no sense to assign a pregnant woman an analysis for bound (total) tetraiodothyronine. During gestation, the concentration of a special transport protein that binds the hormone increases. Therefore, this indicator will almost always be outside the normal range, but this increase will not have any diagnostic value. But the excess of the norm of the concentration of TSH during the period of gestation indicates serious problems. This situation can adversely affect both the health of the mother and the health of the unborn child.

Exceeding the level of thyroid-stimulating hormone indicates a lack of thyroid substances. To make the thyroid gland work more actively, the pituitary gland sends a chemical signal to the organ. With prolonged excess of the level of TSH, the maternal iron may undergo diffuse and nodular changes. The organ will begin to change and grow in order to capture the required amount of iodine salts, but the degree of synthesis will not increase. The state of hypothyroidism will remain. The child’s body will also suffer, because the nervous system, led by the brain, cannot form normally in the absence of iodine-containing hormones.

According to research, pregnancy against the background of an extremely low concentration of specific substances of the thyroid gland most often ends in miscarriage. A child who was born against the background of a serious excess of TSH levels may be born with mental retardation. However, this situation can be easily changed and the hormonal status of a pregnant woman can be brought back to normal by taking synthetic hormonal drugs.

Sometimes doctors strongly recommend artificial termination of pregnancy due to imaginary threats to the intellectual development of the child. As statistics and medical practice show, in the 21st century it is almost impossible to give birth to a mentally handicapped child due to a lack of TSH. Under no circumstances should a pregnancy be terminated. The doctor who gives such recommendations is clearly not qualified enough.

Thus, when conducting an analysis, the purpose of which is to assess the general condition of the thyroid gland, it is necessary to investigate not only specific substances, but also those that have a direct effect on the functioning of the organ: the pituitary hormone TSH and antibody proteins. The thyroid gland performs a basic function necessary for the normal and stable functioning of the whole organism.

Depending on the alleged disease, the tests vary. In one case, it is necessary to examine the blood for some antibodies, in the other case, for others. Some substances act as tumor markers, but donating blood to determine their level is worth it only in a few limited cases, and the results are interpreted ambiguously.

The times of rationing indicators of hormonal blood tests are long gone. The norms are calculated by various clinics independently, based on the equipment used, chemicals and their own methodology. Therefore, in each clinic the result will be different. Trying to interpret the results of different clinics on an equivalent basis is an empty business, since these indicators cannot be recalculated in any way.

Some standards, from which specialists are repelled, still exist, and they are enshrined in medical documentation of a global scale. Only a doctor can correctly decipher and interpret the descriptions of laboratory tests. The patient himself runs the risk of making a mistake, misdiagnosing himself and causing great harm to his body by resorting to self-treatment.

Testing for thyroid hormones does not require any preparation or special rules. All the information about this on the net is nothing more than a fiction or delusion of the average layman graphomaniac without a medical education. When referring a pregnant patient to an endocrinologist, it is important to remember that in this state, the hormonal background changes dramatically, and a special approach to blood testing is required.