What is thyroid 4 test?

The thyroid function tests (also known as TFTs) are a series of blood tests used to assess the function of the thyroid gland. The thyroid gland is an endocrine gland in the neck that produces thyroid hormones, which regulate a variety of bodily functions including metabolism, growth and development, and body temperature.

The TFTs measure the levels of different hormones and other substances related to the thyroid gland, including:

- Thyroid stimulating hormone (TSH): TSH is produced by the pituitary gland in the brain. It stimulates the thyroid gland to produce thyroid hormones.

- Thyroid hormones (T3 and T4): T3 (triiodothyronine) and T4 (thyroxine) are the two main thyroid hormones. They are produced by the thyroid gland and released into the bloodstream.

- Free T3 (fT3) and free T4 (fT4): Free T3 and fT4 are the unbound forms of T3 and T4, which are not attached to proteins in the blood. They are considered more accurate measures of thyroid function compared to total T3 and T4 levels.

- Thyroid autoantibodies: Thyroid autoantibodies are antibodies produced by the immune system that are directed against the thyroid gland. They are often found in people with autoimmune thyroid diseases such as Hashimoto's thyroiditis and Graves' disease.

The TFTs are typically ordered when someone has symptoms of thyroid dysfunction, such as fatigue, weight gain or loss, changes in appetite, mood swings, menstrual irregularities, or changes in heart rate or blood pressure. They may also be ordered to monitor the treatment of thyroid disorders, such as hypothyroidism (underactive thyroid) or hyperthyroidism (overactive thyroid).

The results of the TFTs can help diagnose thyroid disorders and determine the appropriate treatment. The doctor will consider the levels of different hormones and any symptoms the person is experiencing to make a diagnosis.