How many items are there in thyroid hormone tests

The thyroid gland is an organ in the human body. Its main job is to secrete thyroid hormones, which have a huge impact on the body. If some essential elements are lacking in the body, it will cause thyroid disease. If you want to check, how many thyroid hormone tests are there? First of all, everyone should understand the necessity of thyroid hormone tests. What symptoms of the body can be understood by checking thyroid hormones.

1. What do the five thyroid examination items check?

Thyroid disease is one of the common diseases of the neck. The thyroid gland is one of the important tissues in the neck. When the hormones it secretes are appropriate, it is an essential factor in promoting the normal development of the body. When these important hormones are secreted to a greater or lesser extent, it will lead to physical abnormalities. Children in their developmental period will be affected in their development, and recognition will lead to a series of symptoms. So what are the thyroid function tests? There are three thyroid function tests and five thyroid function tests.

1. Free T3 and free T4 are not affected by thyroid hormone binding protein and directly reflect the state of thyroid function. Their sensitivity and specificity are significantly higher than total T3 and total T4, because only free hormone concentration can accurately reflect thyroid function, especially in cases where TGB concentration changes significantly during pregnancy, estrogen therapy, familial TGB increase or deficiency, etc., which is more important. It is currently believed that the combined measurement of FT3, FT4 and high-sensitivity TSH is the preferred option and first-line indicator for thyroid function assessment. Elevated levels of both are seen in hyperthyroidism; decreased levels are seen in hypothyroidism, hypopituitarism and severe systemic diseases.

2. Serum total thyroxine TT4 is the most basic screening test for determining thyroid function. TT4 includes the total amount of protein-bound substances, and is affected by changes in the amount and binding force of TBG and other binding proteins. Elevated TBG is common in high estrogen states, such as pregnant women or patients treated with estrogen, and women taking oral contraceptives. Patients with congenitally high TBG and familial abnormal hyperthyroxinemia have elevated TT4. Patients with hypothyroidism (such as cirrhosis and kidney disease) who take diazepam, testosterone and other drugs and congenitally low TBG have reduced TT4. At this time, physiologically active FT4 and FT3 should be measured to effectively evaluate thyroid function.

3. Serum total triiodothyronine TT3

The amount of T3 in serum that is bound to proteins is more than 99.5%, so TT3 is also affected by the amount of TBG, and the change in TT3 concentration is often parallel to that of TT4.

Increased serum TT3 and TT4 concentrations are mainly seen in hyperthyroidism. Together with FT3 and FT4, they can be used in the diagnosis, disease assessment, and efficacy monitoring of hyperthyroidism and hypothyroidism. However, in the early stage of hyperthyroidism and early relapse, TT3 generally rises very quickly, about 4 times the normal level; TT4 rises slowly, only 2.5 times the normal level. Therefore, TT3 is a sensitive indicator for early Hashimoto's disease efficacy observation and relapse after drug withdrawal. Elevated TT3 and TT4 can also be seen in active hepatitis and pregnancy. Decreased T3 and T4 can be seen in hypothyroidism. In hypothyroidism, TT4 or FT4 decreases earlier than TT3 or FT3. Decreased serum total T3 or FT3 is only seen in the late stage of the disease or in severe cases. In addition, decreased serum total T3 or FT3 can be seen in hypopituitarism, malnutrition, nephrotic syndrome, renal failure, severe systemic diseases, etc.