The thyroid gland is an organ whose normal work is not visible to us. But once there are some malfunctions in his activity, as the whole body suffers, a person begins to feel a whole set of symptoms. This is due to the fact that thyroid hormone produces hormones - special substances that regulate the proper functioning of many organs of the living system. Their insufficient or excessive amount does not have the best effect on the state of health. To understand the root of the problem helps a special study. How to decipher the results of tests for thyroid hormones, we will find out further.
About the thyroid gland
First, we briefly introduce the organ itself and the substances released by it. This helps in deciphering the results of tests for thyroid hormones.
ShchZ - a small organ whose normal weight varies between 15-20 g. It is distinguished by the release of iodine-containing hormones thyroxine and triiodothyronine. The first contains 4 iodine atoms, which is why the abbreviated name of thyroxine is T4. The second element contains three iodine atoms. Accordingly, the abbreviation triiodothyronine is T3.
Thyroxin is produced by the thyroid gland in much larger quantities than T3. However, in its activity, triiodothyronine “overtakes” it three times. Scientists suggest that T4 is a reserve substance from which T3 is subsequently formed.
Triiodothyronine and thyroxine are found in the body both in a bound and in a free state. Moreover, the active action is for free hormones. When bound, they are only transported to specific tissues and organs.
The functions of thyroid hormones
Why are they so significant? T4 and T3 perform the following important tasks in the human body:
- Responsible for metabolism. In particular, proteins and carbohydrates.
- Responsible for the growth of tissues and bones.
- Provide the normal activity of the cardiovascular, nervous, gastrointestinal systems.
- Responsible for the use of oxygen by the cells of the body, enhancing heat production.
In deciphering the results of blood tests for thyroid hormones, another indicator is important. Abbreviated as TTG. This is a thyroid-stimulating hormone. It is not produced by the thyroid gland, but regulates its normal activity. TSH synthesizes the pituitary gland, a component of the endocrine system, which includes the thyroid gland. The main function of thyroid-stimulating hormone is to stimulate thyroid gland to produce T3 and T4.
Other important indicators
To decipher the results of tests for thyroid hormones, the following indicators are also important:
- Thyroglobulin.
- Antibody elements to thyroglobulin.
- Antibody elements to thyroperoxidase.
- Calcitonin.
- Thyroxin-binding globulin.
The thyroid gland does not synthesize all these substances. However, they also affect her work, help determine malfunctions in the work of the entire endocrine system, and make an accurate diagnosis to the patient.
Who prescribes the analysis?
Deciphering the results of blood tests for thyroid hormones is the prerogative of experienced specialists. Most often it is carried out by those doctors who gave the patient a referral for examination:
- Endocrinologist.
- Cardiologist.
- Therapist.
- Immunologist, infectious disease specialist.
- Gynecologist.
- Psychiatrist and so on.
What is the importance of deciphering the results of tests for thyroid hormones? It allows the doctor to deal with specific problems in the work of the cardiovascular, reproductive, digestive, hematopoietic, and nervous systems.
When is the study scheduled?
When may a comparison of individual patient parameters with the norm of thyroid hormone tests TSH and T4 be required? There are a number of cases:
- Diagnosing the patient with symptoms of thyrotoxicosis (excessive content of thyroid hormones): tremor, weight loss, constant nervousness, tachycardia, etc.
- Diagnosing a patient’s symptoms of hypothyroidism (lack of thyroid hormones): dry skin, overweight, slow speech, bradycardia, memory problems, etc.
- Diffuse enlargement of the organ itself, noticeable by palpation, detected by ultrasound.
- Examination of the patient, additional studies show the presence of nodular formations of thyroid tissue on the thyroid gland.
- Menstrual irregularities.
- Infertility in a woman.
- A sharp change in weight while maintaining the same physical activity, the usual diet.
- Spontaneous abortion.
- Heart rhythm disturbances.
- Dyslipidemia. This is the name for increasing the atherogenic index, indicators for total cholesterol.
- Decreased libido and potency in a male patient.
- Galactorrhea.
- The developmental delay in the child - mental, physical.
When is analysis still needed?
Decryption of tests for thyroid hormones may be required by the doctor in such cases:
- Monitoring drug therapy for thyroid disease.
- Monitoring the patient's condition after surgery - resection of the lobe and subtotal, extirpation of the thyroid gland. It is also necessary after conducting radioisotope therapy.
- TSH analysis is an integral part of neonatal screening. That is, studies of the health status of a newborn baby. In Russia, this analysis is required for the timely detection of congenital hypothyroidism.
Getting rid of the "masks"
It is important to correlate the results with the norm of tests for thyroid hormones T4 and TSH and for another purpose. Often, increased or decreased thyroid function is “masked” by other serious diseases and disorders.
Thyrotoxicosis (excessive production of T4 and T3) is very similar in clinical manifestations to the following:
- Atrial fibrillation.
- Tachycardia.
- Panic attacks.
- Insomnia.
- Arterial hypertension and so on.
Hypothyroidism (low secretion of hormones by the thyroid gland) is similar in manifestation to such pathologies:
- Infertility
- Dementia
- Iron deficiency anemia.
- Obesity.
- Chronic Depression
- Menstrual irregularities.
- Tunnel Syndromes.
- Chronic constipation.
- Hearing loss and so on.
Analysis Preparation
The standards for analyzes of thyroid hormones in men, women and children will be presented below. Now no less important information is the correct preparation for taking a blood sample for research:
- It is advisable to plan the procedure in the early morning - up to 10 hours.
- Blood sampling is exclusively on an empty stomach. It’s best if your last snack takes 8-12 hours.
- At this time, you should also not drink sweet drinks, juice, tea, coffee, chewing gum and refreshing sweets. Only clean drinking water without gas is allowed.
- Refuse alcohol a day before the event.
- The hormones prescribed for you should be taken only after taking blood for a sample.
- The last smoked cigarette - no later than an hour before the procedure.
- Before taking blood, be sure to sit in a relaxed position for 10-15 minutes.
- In the morning before the procedure, discard the ECG, ultrasound, X-ray examination, physiotherapy.
- Blood sampling for this analysis is allowed only after 2-4 days after an X-ray examination using a contrast medium.
Normal performance
Having passed a blood sample for examination, patients are interested, for example: "What is the norm of tests for thyroid hormones in women - free thyroxine?". Note that there is no clear indicator. The hormonal level depends on many factors at once - gender, age, stage of development (childhood, puberty, menopause in women). In addition, even the season of the year and the time of day when the blood was taken will affect him!
Therefore, we present the average norms of analyzes for thyroid hormones in children and adults:
- TSH (letter reduction from thyroid-stimulating hormone) in μI / ml - 0.4-4.
- Free T4 (thyroxine) in pg / ml - 0.8-1.8, in pmol / l - 10-23.
- Total T4 in nmol / L - 66-181.
- Free T3 (triiodothyronine) in pg / ml - 3.5-8, in pmol / l - 5.4-12.3.
- Total T3 in nmol / L - 1.2-3.1.
- Normal thyroid globulin is less than 50 ng / ml, with iodine deficiency less than 70 ng / ml, after thyroidectomy less than 1-2 ng / ml.
- AT-TPO (elements-antibodies to thyroid peroxidase) in the borderline value - 30-100 IU / ml, positive results - more than 100 IU / ml, negative results - less than 30 IU / ml.
- AT-TG (elements-antibodies to thyroglobulin) in honey / l - less than 100.
When checking, for example, the norm of thyroid hormone tests for TSH in women, keep in mind that each laboratory has its own table with normal indicators of results, whose values can shift up or down from the average.
Deviations from the norm
Now move on to the next topic. Checking the norm of tests for thyroid hormones in children on TSH, you noticed deviations up or down. What does that mean? An accurate and comprehensive answer will be given only by the specialist who referred the patient for analysis.
We will analyze the main causes of deviations for one or another indicator:
- TTG. An increase, as a rule, is a consequence of primary hypothyroidism or secondary thyrotoxicosis. Underestimated rates are found in secondary hypothyroidism and, conversely, primary thyrotoxicosis.
- T4 Indicators above normal - manifest thyrotoxicosis. Low values - manifest hypothyroidism.
- T3 High indicators here - most often, a consequence of manifest thyrotoxicosis, low - manifest hypothyroidism.
- Thyroglobulin. Increased rates most likely indicate the development of cancer, the recurrence of a cancer tumor after radical therapy. In addition, high values may indicate thyroid adenoma, subacute thyroiditis.
- AT-TPO. What does a high antibody titer mean? Most often, it is evidence of postpartum thyroiditis, Graves disease, Hashimoto thyroiditis.
- AT-TG. Deviations can speak of various autoimmune pathologies of the thyroid gland.
Combinations of indicators
We will also analyze what may mean a different combination of deviations from normal indicators:
- Elevated TK and T4, unreduced thyroid stimulating hormone. Interpreted as a laboratory effect, euthyroidism.
- High TSH, as well as high rates of thyroid hormones - secondary hyperthyroidism, pituitary adenoma is hormone-active.
- T3 and T4 are normal, the level of thyroid stimulating hormone is reduced - subclinical thyrotoxicosis.
- Low rates of TSH and low rates of thyroid hormones - secondary hypothyroidism.
- Decreased T3 and T4, unreasonable thyroid stimulating hormone - euthyroidism, laboratory effect.
The most possible diseases
Knowing the norm of tests for thyroid hormones in women (AT-K-TPO, for example), the doctor can judge the patient’s presence of one or another endocrine, autoimmune disease. Let us briefly describe the diseases that this examination helps to diagnose:
- Thyrotoxicosis (hyperthyroidism). Here, the thyroid gland begins to work more actively than required. There are primary thyrotoxicosis - TSH in the blood is lowered, secondary - TSH values are high. A disease can accompany pituitary adenoma.
- Hypothyroidism With this disease, the thyroid gland, on the contrary, does not work actively enough. Primary hypothyroidism is elevated TSH, and secondary hypothyroidism. They talk about the defeat of the pituitary gland.
- Perry's syndrome, Graves disease, diffuse toxic goiter. Diagnosis is based on high antibody scores.
Pregnancy screening
In conclusion, we will discuss this important topic. As you know, pregnancy will affect thyroid function and, at the same time, complicate laboratory tests.
A woman carrying a child should remember the following:
- In the first trimester, 20-25% of women have physiological thyrotoxicosis. T3 and T4 are increased here, and TSH, on the contrary, is reduced.
- During pregnancy, indicators of thyroid stimulating hormone may remain below normal, be suppressed. T3 and T4 - on the upper frame of the norm or even slightly higher than it.
- If a pregnant woman is diagnosed with persistent thyrotoxicosis, symptoms of autoimmune damage to the thyroid gland, then she is prescribed the appropriate therapy - medication or even surgical (surgical).
- Low thyroid function is undesirable. These are TSH values of more than 2.5 μMU / ml in the first trimester, and indicators for it are higher than 3 μMU / ml in the 2nd and 3rd trimester. Hypothyroidism is dangerous for termination of pregnancy, the development of abnormal abnormalities in the child. To prevent this, a woman is prescribed appropriate hormone therapy.
Analysis for thyroid hormones is true and comprehensive only your doctor can decipher! The fact is that the norms on them are extremely mobile, they depend on many factors. In addition, each laboratory has its own table with average indicators. Hence, this article is material for familiarization with the topic, and not a guide to self-diagnosis.