Health & Fitness

The thyroid gland is a tiny organ located in the front of the neck. Weighing less than one ounce, it is made up of two halves, called lobes, that lie along the trachea (windpipe); the thyroid is joined together by a narrow band of thyroid tissue, known as the isthmus. The thyroid glands function is to take iodine, found in many foods, and convert it into thyroid hormones: thyroxine (T4) and triiodothyronine (T3).

Thyroid cells are the only cells in the body which can absorb iodine. These cells then combine iodine and the amino acid tyrosine to make T3 and T4. T3 and T4 are then released into the blood stream and are transported throughout the body where they control metabolism. Every cell in the body depends upon thyroid hormones for regulation of their metabolism. There are a number of thyroid blood tests that can effectively identify a malfunction within the thyroid gland and help prevent serious problems before they arise.

Some Thyroid Blood Tests
The most commonly used thyroid blood test is the measurement of serum thyroid hormones: T4 by RIA (radioimmunoassay). The T4 blood test reflects the amount of thyroxine in the blood; if the patient does not take any type of thyroid medication, then this procedure is usually a good measure of thyroid function.

Another blood testing procedure for determining thyroid health is the TRH Test. Currently, it is the most sensitive test in detecting early hyperthyroidism, and is sometimes used to measure if the pituitary gland is functioning. Patients who show too much response to TRH–the hormone released by the hypothalamus–may be hypothyroid. Cancer patients who are taking thyroid replacement can take the TRH test to see if they are on sufficient medication.