Thyroid tests, in a nutshell and substance, tell us if the thyroid gland is functioning well. The thyroid is a butterfly-shaped gland, which is located in the anterior region of the neck. Its volume is slightly lower in women than in men: from 6 to 12 ml against measures up to 16 ml. The thyroid produces two types of hormones: T3 (triiodothyronine), T4 (Thyroxine) and calcitonin. The first two are secreted by another type of hormone released by the pituitary gland. However, it too is regulated by TRH, a hypothalamic hormone. The secretion of TSH is pulsatile, that is, it is done approximately every two hours, and increases just before the night’s rest. This activity can be prevented by taking somatostatin and glucocorticoids. The T3 hormone, composed of iodine atoms, it is generally produced together with thyroxine (T4). The latter is transformed in the peripheral tissues into triiodothyronine. In the bloodstream, the optimal concentration is around 80 to 180 mg / dl.Thyroid tests Thyroid screeningto quantify blood levels of thyroid hormones T3 and T4 and pituitary hormone TSH and one of the primary screening tests for thyroid. If the TSH is high, it means that the thyroid is not functioning properly (we speak of hypothyroidism). If, on the other hand, it is low, it is possible that the thyroid gland is working too much (called hyperthyroidism). The test itself consists of a blood sample aimed at testing the levels of TSH (Thyroid Stimulating Hormon) that is secreted by the pituitary gland. Also called Thyrostimulating Hormone, when necessary, this hormone stimulates the thyroid to produce the hormones T3 and T4, which are modulated according to the needs of the organism. In turn, the hormones T3 and T4 when they have reached adequate levels, inhibit the production of TSH. These exams, compared to a time,Hormones FT3 and FT4
FT3 is a hormone produced by the thyroid gland and also resulting from the transformation of thyroxine (T4) in the peripheral organs.
FT4 is instead the main hormone produced by the thyroid, of which the free fraction is measured in the blood. Thyroid ultrasound
This exam allows you to see how the thyroid is made, highlighting its shape, if it is enlarged, if there are nodules and other information. Visual and palpatory examinations of the thyroid
By mechanical examination, the doctor ascertains whether there are abnormalities in the shape and size of the gland. In this way it is also possible to identify the possible presence of nodules. Thyroid scintigraphy
It is an imaging technique. The test provides information on the morphology (shape) and function of the thyroid gland. The examination consists in the administration of a very small amount of a radioactive tracer, which is incorporated by the thyroid tissue. The administration of technetium 99 or iodine 123 takes place intravenously approximately 20 minutes before the examination. Iodine 131 is instead administered orally and the examination is performed 6 to 24 hours later. A special equipment, called ‘gamma camera’, takes care of detecting the radiations emitted by the tracer and sending the information. These are then processed to produce an image of the thyroid in relation to its level of function. The radioactive tracers used in this test are technetium (Tc-99m pertechnetate) or isotopes of iodine, the precursor of thyroid hormones (iodine 123 or iodine 131). The examination is usually prescribed after the thyroid ultrasound, when this has shown the presence of nodules.The different types of thyroid nodules
The radioactive tracer allows to distinguish the different types of nodules. Among these are the so-called hot , or hyperfunctioning, nodules. These are areas that appear more colorful as they are made up of more active tissue than the surrounding one. These are usually benign nodules. Their presence can indicate situations of thyrotoxicosis. The so-called cold or hypofunctional nodules, on the other hand, are formed by little or no active tissue. In some cases they may be of tumor origin.
These exams are not painful, they are done in a rather short time and, once performed, you can return to normal life as always. The only precaution is not to come into close contact with pregnant women or children for 24-48 hours depending on the tracer used: technetium or iodine 123 in the first case and iodine 131 in the second. The needle aspiration or needle biopsy
Also known as needle biopsy or biopsy, needle aspiration is a diagnostic technique that allows you to take biological material through a very thin needle. Typically these are tissues and cells taken from the thyroid. The samples taken are then subjected to laboratory tests such as cytological examination (study of the cells) in the case of needle aspiration or histological (observation of tissues) in the case of biopsy. The examination is performed when previous imaging tests have shown the possible presence of lesions or abnormal formations. Even if you use a needle, the examination is generally not painful and is carried out in a simple and safe way: it only takes a few minutes and does not require anesthesia. Scientific sources
Webmd – American Thyroid Association – AIRC.
The information on this page does not replace the doctor’s opinion.
