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A blood test for TSH is a laboratory study of the levels of thyroid-stimulating hormone produced by the pituitary gland. With such an examination, it is possible to identify various pathological processes occurring in the thyroid gland, and accordingly diagnose the diseases caused by these pathologies.
Typically, such an analysis is carried out in combination with other thyroid hormones, the concentration of which also determines the stable functioning of the thyroid gland.
What is this analysis? How to prepare for it? We will answer these questions in the next article.
What is the TSH hormone
Other names for TSH are thyrotropin or thyroid-stimulating hormone. This substance is produced in the pituitary gland of the brain, which controls all the glands of the endocrine system in the human body.
In turn, the TSH hormone is responsible for the normalization of thyroid function and ensures its stable operation. It also controls the flow of iodine from the blood plasma into the cells of the thyroid gland.
Another function of thyrotropin is to activate the production of the hormones thyroxine and triiodothyronine by the thyroid gland. And the concentration of TSH directly depends on the concentration of T3 and T4 in the body. With an increase in their number, the amount of thyrotropin decreases markedly. Conversely, a decrease in the number of T3 and T4 leads to an increase in the production of TSH.
T4 and T3 thyroid hormones play an important role in energy metabolism, stabilize the patient’s nervous system and mental state, affect growth, hearing and vision, and are also responsible for the normalization of the cardiovascular system.
Triiodothyronine and thyroxine also affect intellectual abilities, speed of thought processes and muscle activity. In addition, they significantly affect the reproductive and sexual functions of the body, regulate the menstrual cycle in women, and are responsible for the normal functioning of the gastrointestinal tract. With their help, the metabolism in the body proceeds. T3 and T4 activate the synthesis of fats, proteins and carbohydrates, nucleic acids, retinol and phospholipids.
Thyrotropin is formed under the direct participation of the central nervous system and hypothalamic neurons. Any changes in the production of this hormone lead to hormonal disruptions. Its deficiency provokes the development of hypothyroidism or thyrotoxicosis. With such a pathological process, the synthesis of T3 and T4 significantly increases, which leads to a decrease in the activity of the pituitary gland.
With a significant decrease in the content of TSH in the blood, hyperplasia is diagnosed – a disease in which the thyroid gland increases significantly. This eventually leads to the so-called “goiter”. If the level of such a hormone in the blood plasma is increased, then we can judge the development of hypothyroidism, characterized by a deficiency of thyroid hormones and impaired adrenal function.
Also, a decrease in the concentration of TSH may indicate the occurrence of tumors or diseases of a psychological nature.
The effect of the TSH hormone on the human body can be characterized by the following factors:
- participation in heat exchange processes;
- controlling the production of red blood cells;
- participation in the production of glucose;
- activation of metabolic processes;
- support and stabilization of the functions of the respiratory system;
- improving the absorption of oxygen in the cells and tissues of the body.
When is a TSH test ordered?
The level of thyrotropin in the blood is measured in microunits per liter or honey per liter. An analysis is prescribed for the concentration of this hormone by a therapist or endocrinologist in the absence of a menstrual cycle, prolonged depression, suspected thyroid hormone deficiency or thyroid goiter, taking a course of hormonal therapy, female and male infertility, lack of potency, cardiovascular pathologies, delayed intellectual and sexual development in children, muscle damage and low body temperature, alopecia or baldness.
In this case, you should know that there are many different factors that affect the concentration of this hormone in human blood.
For example, the highest level of TSH is reached at night, and the lowest – in the evening – from five to seven o’clock. If the patient is awake at night, then the production of thyrotropin is significantly reduced.
During pregnancy and breastfeeding, the level of this hormone is significantly reduced, and this is absolutely normal. Taking various medications can also affect the concentration of TSH in the body.
Preparation and procedure
In order for a blood test for TSH to give more accurate results, a few simple rules must be followed before taking it:
- Before the analysis, stop the use of any medications, vitamins, iodine-containing and hormonal preparations.
- Three days before the analysis, it is necessary to exclude alcoholic beverages from consumption, refrain from smoking, heavy physical and emotional stress.
- It is necessary to donate blood in the morning on an empty stomach, refusing to eat twelve hours before the analysis. It is recommended to drink a glass of non-carbonated mineral water.
A blood test for the thyrotropin hormone involves taking blood from a vein. The study of the obtained material is carried out by the method of chemiluminescent immunological analysis on microparticles. With previously identified violations of the thyroid gland, this study should be carried out twice a year. It is advisable to always do it in the same laboratory and at the same time. Since different laboratories use different equipment, methods and reagents, which can give completely different results.
TSH blood test results
Self-interpretation of the results, especially with identified deviations, is unacceptable. You need a mandatory consultation with a general practitioner or endocrinologist, who, based on the analysis, preliminary history and other related factors, will be able to correctly diagnose the disease and prescribe the necessary treatment.
The norm of thyroid-stimulating hormone in the blood of an adult is 0,4-4,0 mU / liter, in a newborn – 1,1-17,0 mU / liter.
Thus, it can be noted that the concentration of thyroid-stimulating hormone gradually decreases with age, which is why only a qualified specialist can determine the norm for a particular person, especially for aged patients. When deciphering the results of a blood test for thyroid-stimulating hormone, an endocrinologist takes into account various individual characteristics of patients: gender, age, body weight, previous diseases, the state of internal organs, taking medications, and so on. An increase in TSH levels indicates the presence of the following pathologies:
- mental and somatic disorders;
- adrenal insufficiency;
- syndrome of unregulated production of TSH;
- hypothyroidism of various origins;
- resistance of thyroid hormones;
- inflammatory processes of the thyroid gland;
- tumor processes in the lungs or mammary glands;
- preeclampsia – a severe complication in late pregnancy;
- lack of iodine;
- genetic anomalies.
Also, an increase in the concentration of thyrotropin is observed with cholecystectomy – removal of the gallbladder, with hemodialysis, taking steroid drugs and with significant physical exertion.
A decrease in the level of thyrotropin hormone signals the following pathological conditions:
- injuries or necrosis of the pituitary gland, including postpartum;
- stressful conditions, mental disorders and mental disorders;
- poisoning with endocrine hormones of various origins – thyrotoxicosis;
- insufficiency of the hypothalamus or pituitary gland;
- Graves’ and Plummer’s diseases;
- infectious and inflammatory processes in the thyroid gland.
In conclusion
A blood test for TSH allows timely identification and diagnosis of various pathological processes occurring in the human body. Deviation of the TSH level from the reference standards in one direction or another entails negative consequences, therefore it is extremely important to consult your doctor if you feel any changes. Timely diagnosed disease and treatment can prevent various serious and severe consequences. At the same time, you should know that hormonal disorders in the initial phase are easily treatable, while advanced diseases require more than one course of therapy.