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

Hormones and their role

The main hormones that are studied:

1. Triiodothyronine (T3);
2. Tetraiodothyronine (T4). It is also called thyroxine;
3. Thyroid-stimulating hormone (TSH);

The thyroid gland produces 3 substances:

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

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

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

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

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

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

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

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

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

diffuse toxic goiter;

nodular goiter;

subacute de Crevin's thyroiditis;

postpartum gland dysfunction;

thyroiditis (Hashimoto's);

idiopathic hypothyroidism;

autoimmune thyroiditis;

non-thyroid autoimmune diseases.

When is the test prescribed?

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

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

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

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

The reasons for such an appointment may be:

• Sudden changes in a person’s weight;
• Difficulty conceiving a child;
• Heavy pregnancy;
• Menstrual irregularities in women;
• Delayed physical or mental development of the child.

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

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

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

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

Standards for adults

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

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

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

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

Norms for children

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

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

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

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

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

Afterwards it stabilizes at around 4.15 mIU/l.

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

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

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

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

Preparation for delivery of biomaterial

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

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

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

Preparation for analysis also includes other activities:

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

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

We pass the analysis

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

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

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

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

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

The analysis timeframe is up to 5 days.

What do deviations mean?

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

• Weight loss;
• Cardiopalmus;
• Sweating.

There are 3 types of hyperthyroidism:

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

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

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

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

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

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

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

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

An increase in T4 occurs in a number of cases:

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

Low thyroxine levels are observed when:

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

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

For preventive purposes, it is necessary to undergo a medical examination every 1-2 years. If you have health problems, as well as a hereditary tendency to pathologies of the endocrine system, laboratory diagnostics should be regular.

Important! A referral can be obtained from a general practitioner or endocrinologist, or tests can be done privately.

Tests to check the thyroid gland are performed for the following indications:

• fatigue, drowsiness;
• excessive excitability;
• sudden mood changes;
• tachycardia and other heart rhythm disturbances;
• bulging eyes;
• insomnia;
• sweating;
• causeless increase in body temperature;
• problems in the sexual sphere: infertility, impotence, menstrual irregularities, decreased libido;
• problems with weight and appetite;
• alopecia;
• enlargement of the thyroid gland, the appearance of goiter;
• mental retardation in a child;
• control of existing pathologies;
• monitoring the results of therapy.

What tests are needed

Laboratory tests are basic in the entire diagnostic scheme for diseases of the endocrine system. Only after they have been carried out, the doctor determines the auxiliary research methods that are required in a particular case. What tests to take for the thyroid gland are decided on an individual basis.

Most often, blood donation is prescribed to determine the following indicators:

• TSH - thyroid-stimulating hormone of the pituitary gland;
• T3 - triiodothyronine;
• T4 - thyroxine;
• ATTG - antibodies to thyroglobulin;
• ATTPO - antibodies to thyroid peroxidase;
• Calcitonin is a basic tumor marker.

Characteristics of indicators

How to check the thyroid gland, that is, what tests demonstrate its condition, should be considered in more detail. To do this, you need to familiarize yourself with the characteristics of the main indicators and their functions.

• TSH is produced by the pituitary gland and affects the activity of the thyroid gland and other glands of the endocrine system. The activity of these organs depends on its quantity.
• T3 is an active thyroid hormone that has a suppressive effect on the body in this system.
• T4 - combines with protein and forms a depot for the hormone thyroglobulin.
• Antibodies to TG - their presence in large quantities indicates an autoimmune process.
• Antibodies to TPO are a clear sign of an autoimmune disease of the endocrine system.
• Calcitonin is an indicator of metabolic processes involving phosphorus and calcium, through the assessment of which it is possible to identify oncological pathologies.

Preparing for tests

Test results may be distorted if the patient does not follow the preparation rules, which the attending physician must familiarize him with. Before testing for the thyroid gland, the following conditions must be met:

• In 1 month. The use of hormonal drugs containing T3 and T4 is suspended, unless otherwise prescribed by the doctor.
• In 2-3 days. All foods containing large amounts of iodine are excluded from the diet. Appropriate nutritional supplements are also discontinued.
• Per day. It is necessary to completely give up coffee, alcoholic beverages and smoking. Physical and emotional stress should be controlled and strictly rationed.
• In 12 hours. Blood donation is performed on an empty stomach, so you must refrain from eating 10-12 hours before the procedure.

Since it is correct to take thyroid tests on an empty stomach, the procedure is prescribed in the morning. Venous blood is taken from the patient, so in some cases they are required to take a syringe of the appropriate type with them.

Decoding the results

After collecting venous blood, the patient is sent home, and the material is sent to the laboratory for biochemical testing. Thyroid tests in women and men differ in some respects. For example, the level of thyroxine in women is higher than in the stronger sex. At the same time, the normal range for calcitonin is higher in men.

Important! The laboratory issues a form with an assessment of the indicators; the procedure for deciphering the results itself is the responsibility of the endocrinologist.

Norm

It is possible to independently assess the state of your endocrine system if you know the normal limits for the indicators being studied. We must not forget that the norm of thyroid tests in women and men differs.

If the blood tests for the thyroid gland meet the norm according to all evaluation criteria, the patient does not have to worry about his health. It is possible that there will be a slight deviation in 1-2 indicators due to non-compliance with the rules for preparing for blood donation. In this case, a repeat study will be required, since the data is unreliable.

Signs of abnormalities

What blood tests for the thyroid gland indicate a potential risk of developing pathology? The basis is thyroid-stimulating hormone, free T3 and free T4. The following results indicate the presence of problems:

• Hyperthyroidism - increased T3 and T4 with a simultaneous decrease in TSH.
• Primary hypothyroidism is the opposite situation, that is, thyroid-stimulating hormone is increased, but free T3 and T4 levels remain normal or decrease.
• Secondary hypothyroidism is a pronounced decrease in T3 and T4 with a corresponding increase in TSH.

In autoimmune diseases, a special picture is observed. In this case, the basic characteristics of the thyroid gland may remain normal or deviate in any direction. At the same time, an increased level of antibodies to thyroglobulin and thyroid peroxidase is detected.

Important! The detection of a large amount of calcitonin indicates a disturbance in the circulation of calcium and phosphorus. This sign is one of the early symptoms of cancer pathologies, so timely diagnosis is an important factor in cancer treatment.

Regardless of your health and existing health problems, it is recommended to undergo laboratory examination from time to time. Such simple measures will help avoid the development of serious diseases. Detection of disorders in the early stages is a chance to carry out treatment using conservative methods with minimal consequences for the body.

Blood test for thyroid hormones - when should they be taken? What tests exist, how to take them correctly (preparation), standards, where to take them, price. List of drugs that increase and decrease hormone levels

Thank you

The site provides reference information for informational purposes only. Diagnosis and treatment of diseases must be carried out under the supervision of a specialist. All drugs have contraindications. Consultation with a specialist is required!

Thyroid hormone tests - what is it?

The thyroid gland is an organ of internal secretion, in other words, it belongs to the endocrine system and, accordingly, produces a number of hormones that are involved in the regulation of metabolism in the body, as well as in ensuring the normal functioning of the cardiovascular, reproductive and digestive systems. In addition, thyroid hormones ensure the normal state and functioning of the central nervous system and psyche.

In case of psycho-emotional overload, deficiency of iodine or vitamins, long-term chronic or infectious diseases, unfavorable environmental conditions, harmful working conditions, as well as when taking certain medications, the functioning of the thyroid gland is disrupted, resulting in a deficiency or excess of its hormones in the body, which is manifested by disorders from the cardiovascular, reproductive, digestive and nervous systems.

Depending on the amount of hormones the thyroid gland produces, all its diseases are conventionally divided into three large groups:

• Diseases with hypothyroidism, when the level of thyroid hormones in the blood is reduced;
• Diseases with hyperthyroidism (thyrotoxicosis), when the level of thyroid hormones in the blood is increased;
• Diseases with euthyroidism, when the level of thyroid hormones in the blood is normal, despite the existing pathology of the organ.

Tests for thyroid hormones are usually prescribed in two cases - either a person has signs of hypothyroidism/hyperthyroidism, or as part of a preventive examination when living in regions with endemic iodine deficiency. In the first case, tests are necessary for an accurate diagnosis of the existing disease, and in the second, for the early detection of asymptomatic thyroid pathologies.

What and how many tests are available for thyroid hormones?

• Total thyroxine (T4) – concentration in the blood;
• Free triiodothyronine (T3 free) – concentration in the blood;
• Antibodies to thyroid peroxidase (thyroid peroxidase) – ATPO, anti-TPO – concentration in the blood;
• Antibodies to thyroglobulin (ATTG, anti-TG) – concentration in the blood;
• Thyroglobulin (TG) – concentration in the blood;
• Thyroid-stimulating hormone (TSH) – concentration in the blood;
• Antibodies to TSH receptors – concentration in the blood;
• Antibodies to the microsomal fraction of thyrocytes, antimicrosomal antibodies (AT-MAG) – concentration in the blood;
• Thyroxine-binding globulin – concentration in the blood;
• Calcitonin – concentration in the blood.

In what cases is it necessary to take tests for thyroid hormones?

You should know that if there are signs of hypothyroidism or hyperthyroidism, not all possible tests for thyroid hormones are taken immediately, since this is not necessary. First, the most general tests are taken, which allow us to identify the nature of pathological changes and make a diagnosis in most cases. And only if the results of the primary tests were not enough, then additional tests for thyroid hormones are taken, which the doctor will prescribe.

The priority tests for thyroid hormones, which should be taken immediately if there is a suspicion of a disease of this organ, include the following:

• Total thyroxine (T4) – concentration in the blood;
• Free thyroxine (T4 free) – concentration in the blood;
• Total triiodothyronine (T3) – concentration in the blood;
• Thyroid-stimulating hormone (TSH);
• Antibodies to thyroid peroxidase (thyroid peroxidase) – ATPO, anti-TPO.

It is also necessary to know that taking priority tests for thyroid hormones is indicated for all women and men for the purpose of preventive examination for early detection of organ pathology, especially if they live in regions with unfavorable environmental conditions or work in harmful conditions.

Above, we indicated in which cases it is necessary to take tests for thyroid hormones and which ones. Below in the table we indicate the indications for each test for thyroid hormones.

Preparing for tests for thyroid hormones (how to properly take a blood test for thyroid hormones)

To test for thyroid hormones, you should donate blood from a vein strictly on an empty stomach after an 8-14 hour fast. Therefore, it is optimal to donate blood for hormones in the morning on an empty stomach, after abstaining from eating during the night's sleep. If for some reason it is impossible to take tests for thyroid hormones in the morning on an empty stomach, then this can be done in the daytime, but at least 4 hours after eating. You do not need to follow any special diet before taking the tests.

Two weeks before the tests, stop taking thyroid hormones and two days before - any other medications, and if this is not possible, then you should tell the doctor and laboratory staff about what medications you are taking.

The day before the test, you should exclude psycho-emotional and physical stress, do not drink alcoholic beverages, and, if possible, avoid stressful situations. Before taking the test, you should not smoke for 2–3 hours (at least an hour). Immediately before taking blood for testing, it is advisable to rest for 15–30 minutes and be in a calm state of mind.

Any recent interventions on the thyroid gland (for example, surgery, radiotherapy, etc.) affect the results of hormone tests, therefore the conditions and time of laboratory testing in such cases are prescribed and determined by the doctor.

Analysis for thyroid hormones - on an empty stomach or not?

Standards for testing thyroid hormones

This situation with standards is due to the fact that each laboratory uses various modifications or methods for determining the concentration of hormones, in accordance with which their normal values ​​are established. And since the determination methods are different, each laboratory has its own standards, sometimes very different from each other.

What medications lower and increase thyroid hormone levels?

The level of thyroid hormones in the blood is affected by a fairly wide range of medications, some of which lead to a decrease in the concentration of these substances, and the other, on the contrary, to an increase. Knowledge of such drugs is necessary so that, in the event of testing while taking any medications, it is possible to assess whether the increased/decreased concentration of hormones is caused by them, or whether it reflects a pathology of the thyroid gland. The table below provides a list of medications that can affect the level of thyroid hormones in the blood.

Where can I get tested for thyroid hormones?

Sign up for a blood test for thyroid hormones

To make an appointment with a doctor or diagnostics, you just need to call a single phone number
+7 495 488-20-52 in Moscow

+7 812 416-38-96 in St. Petersburg

The operator will listen to you and redirect the call to the desired clinic, or accept an order for an appointment with the specialist you need.

How long does it take to test for thyroid hormones?

The fact is that to perform an analysis of hormone concentrations, it is necessary to install eight controls. These eight controls are placed each time an analysis is performed. Moreover, the same eight controls are used for the entire series of blood sera under study. Accordingly, whether the concentration of hormones in the blood of one person or twenty people is determined, eight controls will still have to be installed for this series. Due to this circumstance, laboratories prefer to collect several test blood sera and determine the concentration of hormones in them at a time in order to set up eight controls once, for all blood samples at once, rather than doing this for each test blood separately. It is precisely because of this “accumulation” of blood samples in order to determine the concentrations of hormones in all of them at one time that there is a delay in issuing the result.

Private laboratories usually accumulate blood samples only before lunch of the current day, and after 12-00 they start working. Accordingly, they give out the result the next day or in the evening of the same day when the blood was donated for thyroid hormones. In some cases, private laboratories collect blood samples for 2 – 3 days, and in such a case, the results are also released only 2 – 3 days after the blood is donated.

But laboratories of public medical institutions usually accumulate blood samples for hormone tests within 2 to 4 weeks. Accordingly, results are issued by state laboratories only 1–2 times a month. Typically, government laboratories have a designated day when hormone tests are performed, for example, the last Thursday of the month, etc. Accordingly, the results of the analysis will be issued the next day after the analysis is done. Therefore, when it comes to a state laboratory, you need to find out exactly the day when it conducts blood tests for hormones, and to get the result as soon as possible, donate blood, as close to this day as possible.

Price of thyroid hormone tests

Causes and symptoms of hypothyroidism (lack of thyroid hormones) - video

Thyroid gland, hormones and pregnancy – video

Products for the thyroid gland - video

The thyroid gland is an endocrine organ that regulates basic metabolic processes in the body. A blood test for thyroid hormones allows you to determine the causes of disorders of protein and fat metabolism, cardiac activity, nervous system, etc.

The study of the level of thyroid hormones is an important element in the diagnosis of endocrine disorders and is prescribed in cases of detection of pathological enlargement or nodular formations.

Tests that may be prescribed if thyroid disease is suspected:

• thyroid stimulating hormone (TSH);
• total and free thyroxine (T4);
• total and free triiodothyronine (T3);
• thyrocalcitonin (TC);
• antibodies to thyroid peroxidase (AT TPO);
• antibodies to thyroglobulin (AT TG).

Together with the results of ultrasound, analysis of thyroid hormones confirms the development of the following diseases:

• nodular nontoxic goiter;
• diffuse toxic goiter;
• autoimmune thyroiditis;
• malignant tumor of the thyroid gland.

Symptoms for which it is important to determine the amount of hormones to make a diagnosis:

• swelling of the legs, eyelids;
• tachycardia;
• sweating with unknown causes;
• change in voice, hoarseness, rapid weight gain or loss without changing diet;
• hair loss, eyebrows;
• disruption of the menstrual cycle;
• decreased potency;
• swelling of the mammary glands in men.

Hormone studies are also indicated for problems with the cardiovascular, reproductive, and nervous systems to exclude endocrine disorders in diseases with general symptoms (atrial fibrillation, increased blood pressure, nervous disorders, etc.).

Preparing for analysis

In order for the results of tests for thyroid hormones to correspond to real indicators, it is necessary to adhere to a number of rules before the procedure:

• donate blood in the morning on an empty stomach;
• Avoid physical activity before analysis;
• do not drink alcohol on the eve of the study;
• you do not need to skip taking hormonal medications if the medications are prescribed by your doctor;
• Avoid stressful situations a few days before taking a hormone test.

When preparing for analysis of thyroid hormones, the phases of the menstrual cycle in women are not taken into account, since they do not affect the amount of thyroid-stimulating and thyroid hormones in the blood.

Thyroid hormone levels (table)

If there is a suspicion of insufficiency or increased activity of the thyroid gland, a test for TSH, total and free T4 is prescribed. Analysis for total and free T3 is prescribed for suspected T3 hyperthyroidism, as well as for diseases of the liver, kidneys, and heart, as it shows the rate of metabolic processes in the peripheral tissues of the body.

Calcitonin testing is prescribed to detect C-cell hyperplasia in the thyroid gland, medullary cancer and metastases during the treatment of cancer.

Decoding the analysis results

To diagnose autoimmune or endocrine diseases, it is necessary to consider the indicators of hormone tests in combination. To do this, you can use a special table with indicators of basic tests for various pathologies.

Thyroid-stimulating hormone

TSH is the main factor in regulating the functioning of the thyroid gland. Thyroid-stimulating hormone is produced by the pituitary gland and works on a feedback principle: an increase in T3 and T4 leads to a decrease in the concentration of TSH in the blood, and a decrease in the activity of the thyroid gland causes an increase in the production of thyroid-stimulating hormone.

An elevated TSH concentration indicates the following diseases:

• hypothyroidism;
• subacute thyroiditis;
• pituitary tumor;
• endemic goiter;
• Itsenko-Cushing syndrome;
• pituitary tumor;
• hypothalamic-pituitary insufficiency.

Also, a blood test for thyrotropin may have elevated levels after long-term use of corticosteroids, heparin, and aspirin.

A decrease in TSH occurs in the following diseases:

• hyperthyroidism;
• actomegaly;
• psychogenic anorexia;
• secondary amenorrhea;
• delayed sexual development;
• endogenous depression;
• chronic renal failure;
• cirrhosis of the liver;
• long-term use of medications: apomorphine, dopamine, verapamil, phenytoin.

Thyroxine

Thyroxine is the main biologically active substance of the thyroid gland, which is formed from iodine atoms and the amino acid tyrosine. After production, hormones enter the blood, where they are found in free and protein-bound forms. Total T4 is the sum of both forms of thyroxine.

Bound T4 has the greatest diagnostic value in identifying endocrine pathologies. In this case, the analysis indicators may increase or decrease if protein metabolism in the body is disrupted.

An elevated T4 level does not always indicate diseases of the endocrine system, as it can accompany severe diseases of the internal organs (for example, an active form of hepatitis) and be an individual reaction to long-term use of a number of medications (oral contraceptives, etc.).

Triiodothyronine

Triiodothyronine is a thyroid hormone, most of which is formed from T4 in the peripheral tissues of the body (liver, kidneys, muscles). T3 is the main biologically active hormone with a more pronounced effect than thyroxine.

Reduced levels of total and free T3 are observed with:

• a decrease in the rate of peripheral conversion of thyroxine to T3 (occurs in men after 60 years and in women after 70 years);
• long-term therapy with thyreostatics;
• chronic pathologies of the liver, kidneys;
• decompensated cirrhosis of the liver;
• tumors in late stages of development;
• acute heart failure;
• pulmonary failure.

An increase in triiodothyronine in free and bound form indicates the presence of the following pathologies:

• hyperthyroidism in older people;
• T3 hyperthyroidism (occurs with iodine deficiency);
• disorder of protein binding capacity;
• taking medications containing triiodothyronine.

During pregnancy, the T3 level can be almost twice the normal value. As a rule, such processes occur in the last trimester. After childbirth, triioditronine levels in women return to normal within 10-15 days.

Thyroid calcitonin

Calcitonin is a hormone secreted by thyroid C cells. Thyroid calcitonin promotes the deposition of calcium in bones, prevents bone destruction and reduces the amount of calcium in the blood.

An increase in calcitonin indicates oncological processes in the body:

• medullary cancer;
• malignant breast tumor;
• prostate cancer;
• tumor in the lungs.

In addition, high levels of thyrocalcitonin are observed in renal failure, anemia, parafollicular cell pathology and vitamin D overdose.

Antibodies

AT TPO are blood proteins that neutralize the enzyme thyroid peroxidase, from which thyroid hormones are produced. An increase in antibodies to thyroid peroxidase leads to the destruction of follicles and disruption of hormone production.

AT TG are antibodies that neutralize thyroglobulin (precursor proteins of the hormone thyroxine). As is the case with increased TPO AT, high levels of antibodies to thyroglobulin can be accompanied by diseases of the immune system.

The appearance of antibodies indicates possible autoimmune diseases:

• Hashimoto's thyroiditis;
• diffuse toxic goiter;
• nodular toxic goiter;
• infectious inflammation;
• type 1 diabetes mellitus;
• rheumatoid arthritis;
• systemic lupus erythematosus;

If an increase in antibodies occurs during pregnancy, then such a pathological process can have adverse consequences:

• it is possible to develop hyper-or, which leads to negative consequences for the child;
• there is a risk of developing postpartum thyroiditis;
• the risk of miscarriage increases, as antibodies indicate immune dysfunction.

Despite the possible consequences, 5% of men and 10% of women have chronic high levels of antibodies to TPO and TG, which do not cause the development of pathologies of the endocrine glands and other internal organs.

Tests during pregnancy

The functioning of the thyroid gland during pregnancy is regulated not only by the level of TSH, but also by human chorionic gonadotropin (HCG), secreted by the placenta.

In the first trimester, the level of hCG increases significantly, activating the release of total T3 and T4, as a result of which TSH decreases to 0.1-0.4 nmol/l.

In the second and third trimesters, the amount of TSH is normalized, and the T3 and T4 levels may fluctuate slightly.

If during pregnancy an analysis of thyroid hormones shows serious deviations from the norm, this indicates the development of endocrine disorders.

Both during and after pregnancy, the likelihood of developing autoimmune thyroiditis, diffuse goiter, and postpartum thyroiditis increases, so it is necessary to take tests for thyroid hormones during pregnancy and after childbirth.

Why do you need to determine your thyroid hormone levels? The thyroid gland is called the “first violin” of the endocrine system. It produces hormones - biologically active substances that affect various functions of the body, namely:

• metabolic processes;
• cardiac activity;
• central nervous system;
• immunity;
• osteoarticular system;
• gonads;
• health of skin and hair.

Excessive synthesis of thyroid hormones (hyperthyroidism) or, conversely, reduced production (hypothyroidism) lead to the occurrence of many diseases. Therefore, when examining patients, thyroid hormone tests are often performed to identify the cause of the disease and determine the correct treatment tactics.

What role do hormones play?

The gland secretes 2 types of hormones: iodothyronines and calcitonin.

The first type is iodine-containing hormones: thyroxine (T4) and triiodothyronine (T3), they affect almost all body functions. Their formation in gland cells requires iodine and the protein thyroglobulin (TG), as well as the pituitary thyroid-stimulating hormone (TSH), or thyrotropin, which regulates this synthesis process. For example, if thyroid function is reduced, TSH will increase, meaning the pituitary gland sends an increased amount of hormones to the thyroid gland to stimulate its function.

The 2nd group hormone calcitonin plays a major role in the metabolism of phosphorus and calcium in the body. The condition of the bones directly depends on this - their growth and restoration, the quality of their structure.

Who is a hormone test indicated for?

When should you get tested for thyroid hormones? Indications for it are:

1. The presence of goiter (enlargement) of the gland.
2. Cardiac arrhythmias.
3. Neuropsychiatric disorders.
4. Disorder of menstrual function.
5. Infertility.
6. Sexual function disorder.
7. Lack of protein in the body.
8. Increased hair loss.

Thyroid hormone tests are extremely important for women because they affect ovarian function and cause hormonal imbalances.

Important: retardation of children in mental and physical development is also often associated with thyroid pathology. For this reason, analysis of thyroid hormones in such children is mandatory.

What tests are performed, what is their standard?

The table shows the correct analysis for thyroid hormones, that is, with their normal concentration:

Important: an endocrinologist is responsible for interpreting the blood test for thyroid hormones and assessing it.

How to prepare for the test?

Before testing for thyroid hormones, special preparation is required, which consists of the following:

• on the eve of the test, avoid alcohol, do not smoke, you need to have a good rest and sleep;
• in the morning before the test, do not eat or drink;
• those taking iodine-containing drugs should stop taking them 3 days before the study;
• patients on hormone therapy should stop taking hormonal medications a month before taking a thyroid hormone test, unless this will threaten their health.

Important! Thyroid function changes under the influence of various factors. Therefore, without preparing for an analysis of thyroid hormones, it will be impossible to obtain its true picture.

What do the results of thyroid-stimulating hormone tests indicate?

What does a test for thyroid hormones T3 and T4 show? Based on the results of the study, it can be determined that the patient has the following pathology:

1. Hypothyroidism: primary or secondary.
2. Hyperthyroidism.

Hypothyroidism

Decreased thyroid function can be primary or secondary. Primary is caused by a pathological process in the gland cells themselves (inflammation, tumor, congenital anomaly). In this case, the analysis indicators will be as follows: the content of T3 and T4 is reduced or within normal limits, and TSH will be increased (compensatory).

In secondary hypothyroidism, the lack of hormones is associated with weak stimulation of the thyroid gland by the pituitary gland, that is, a lack of TSH. The content of all gland hormones, as well as thyrotropin, will be reduced. This indicates trouble on the part of the brain structures - the pituitary gland, hypothalamus (as a result of a tumor, inflammation, injury).

Hyperthyroidism

Increased hormone production can also be primary or secondary. Primary hyperthyroidism is associated with a disease of the gland itself, secondary hyperthyroidism is associated with iodine deficiency (endemic goiter), when the gland produces compensatory hormones. In both cases, the content of T3 and T4 will be increased, and the level of TSH will be decreased, that is, the pituitary gland ceases to stimulate the already active thyroid gland.

Important! Even a slight deviation in the level of thyroid-stimulating hormones requires timely treatment. Long-term hormonal imbalances lead to irreversible changes in the body.

How are antibodies assessed?

Antibodies to thyroglobulin (AT-TG) are normally present in the blood in small quantities. An increase in their number indicates inflammatory autoimmune inflammation or the presence of a malignant tumor, a specific immune response.

Antibodies to thyroid peroxidase (AT-TPO) are formed when the immune system fails when it begins to perceive the enzyme involved in the synthesis of thyroid hormones as a foreign body. As a result, an autoimmune process develops. An increase in the level of AT-TPO indicates the possible presence of autoimmune thyroiditis or Hashimoto's goiter, Graves' disease (diffuse toxic goiter).

What does a change in calcitonin levels mean?

Calcitonin regulates the level of calcium and phosphorus and prevents their leaching from the body. This function is especially important for pregnant women and children, when the skeletal system is forming and growing. Its antagonist is parathyroid hormone, produced by the parathyroid glands, which, on the contrary, removes calcium and phosphorus ions from the body.

The level of calcitonin changes throughout the day, for example, after eating it increases, and on an empty stomach it approaches zero. This is taken into account when taking the analysis.

Important! The greatest significance of calcitonin is that it is a tumor marker for thyroid cancer, that is, its sharp increase indicates the presence of a tumor, the cells of which intensively produce this hormone. In addition, calcitonin can be increased in case of kidney and liver failure.

The results of tests for thyroid hormones and antibodies are taken into account during a comprehensive examination and play a large role in the diagnosis of diseases and the choice of methods of treatment.