Thyroid Function Test

A thyroid function test is a blood test that measures how well your thyroid gland is working.

The thyroid is a small, butterfly-shaped gland located in the neck, just below the Adam's apple. It produces hormones that control many bodily functions, such as metabolism, heart rate, and body temperature. When something is wrong with your thyroid, it can cause a wide range of symptoms such as fatigue, weight gain, depression, and even heart problems. To diagnose a thyroid disorder, your doctor may order a thyroid function test.

A thyroid function test measures the levels of two hormones in your blood: thyroxine (T4) and triiodothyronine (T3). These hormones play an important role in regulating your metabolism, so if your levels are too high or too low, it may indicate a thyroid disorder.

The test also measures levels of thyroid-stimulating hormone (TSH). TSH is produced by the pituitary gland and stimulates the thyroid to produce more T4 and T3. If your TSH levels are high, it may mean that your thyroid isn’t working properly and may need to be treated.