Thyroid Function Tests

Thyroid hormone is one of the most important hormones in the body. Thyroid function tests, on the other hand, are tests that show whether the hormone in question is working properly.

Thyroid Function Tests

Thyroid function tests are blood tests to analyse the function of the thyroid gland. Plasma TSH, free T4 and total T3 are analysed. Normal TSH levels are between 0.37 and 4.7 mIU/L and these vary by lab. Plasma T4 levels are between 60 and 150 nmol/L and T3 levels are between 1.2 and 2.7 nmol/L.

Some changes in the thyroid gland originate from an autoimmune disease. In these situations, it is of interest to measure the levels of certain autoantibodies, such as anti-thyroglobulin, anti-thyroid peroxidase, or anti-TSH receptor antibodies.

When Are Thyroid Function Tests Done?

Thyroid hormones are necessary for the normal metabolism of the individual. They interfere with the metabolism of carbohydrates, lipids, proteins and affect organs as important as the heart.

The function of the thyroid gland is controlled by another gland called the pituitary gland. Located at the base of the skull, this gland produces a hormone called thyrotropin, or TSH, which is a thyroid stimulating hormone.

It is very sensitive to changes in circulating levels of TSH, T4 and T3 hormones. A small increase in free T4 concentration causes a large decrease in TSH concentration and vice versa.

These tests are used to identify the following diseases:

  • Goiter
  • Hyperthyroidism
  • Hypothyroidism
  • Thyroid nodule

How Are Thyroid Hormone Tests Done?

Thyroid hormone tests are performed very simply. It is carried out in the form of a blood test at the request of the doctor in various health institutions. It is possible to learn TSH, TS4 and TS3 values ​​with a tube of blood taken from the patient. These tests should be done in the morning and on an empty stomach.

These tests measure the amount of TSH in the blood of individuals. It is especially applied to patients with symptoms related to goiter and thyroid disorder. In addition, TSH, TS3 and TS4 values ​​are checked in routine blood tests and examinations performed on individuals. It is very important to control these values, which can rise and fall, especially during pregnancy. These tests, which are related to thyroid hormone, which affects all functions of the body, should be done at regular intervals.