FT4 (Free Thyroxine) Test & TSH (Thyroid-Stimulating Hormone) Test

What is a Thyroid Function Tests (TFT)?

in the front of the neck. These hormones support the body's ability to grow, mature sexually, and obtain energy from food, among other functions. The thyroid is stimulated to produce more thyroid hormone by Thyroid-stimulating hormone (TSH). This hormone is produced by the pituitary gland, located near the brain's base. To maintain normal hormone levels, the thyroid and pituitary gland communicate repeatedly. The TFT test measures the level of T4, T3, and thyroid-stimulating hormones in the body.

When is the thyroid test done?

A doctor may recommend a TFT test to check how the thyroid is functioning

• To detect hyperthyroidism or hypothyroidism
• In case the doctor suspects Graves disease
• To detect Thyroid nodules or cancer
• To check for Hashimoto's disease.

What are the components of a TFT Test?

The thyroid test measures the following

• Total T4
• T3
• Total T4 assesses the overall concentration of thyroxine in the blood, including the quantity bound to blood proteins that aid in the hormone's circulatory transportation.
• FT4 test solely assesses thyroxine that isn't bound to proteins. This portion of T4 in the blood impacts how the body's cells function.

Free T4 test results can aid in diagnosing hyperthyroidism or hypothyroidism and assist in deciding the exact management of the disease.

• T3 total test: The T3 test evaluates the blood levels of the additional significant thyroid hormone. It frequently aids in the hyperthyroidism diagnosis.
• TSH test: The thyroid's effectiveness can be assessed using a thyroid stimulating hormone (TSH) test. If a thyroid disorder stops the gland from making enough thyroid hormone, the pituitary gland releases more TSH into the blood. When the thyroid produces too much thyroid hormone, the pituitary produces less TSH.

What is the standard reference range for the Thyroid test?

The normal range of

• T4 is suggested to be 77–155 nmol/l,
• T3 to be 1.2–2.8 nmol/L
• TSH to be 0.3–4 mU/l
• The hormones above or below the normal range indicate hyperthyroidism or Hypothyroidism.

How is the thyroid test done?

• The sample is collected from the vein.
• The result is expected within a day or two
• This test poses no risk to the patient.
• Fasting is not required.