Thyroid Profile

The Thyroid Hormone Profile measures the levels of unbound free hormones which are available to the tissues, and reflects a true measure of the body's metabolic rate. Disorders of the thyroid are among the most common diseases of the endocrine glands, particularly in women.

Thyroid function decreases with age and an underactive thyroid or hypothyroidism is most common in menopausal and post menopausal women.Symptoms of underactive thyroid include dry and coarse skin, weakness and lethargy, constipation, weight gain, slow pulse, heavy and irregular periods and depression.

Symptoms of overactive thyroid or hyperthyroidism (thyrotoxicosis) include fast metabolic rate, rapid heart beat, nervousness and palpitations, weight loss despite increased appetite and frequent bowel movements.

Essential Hormones

Thyroid hormones are essential in maintaining and regulating the body’s metabolism. Triiodthyronine (T3) is the most active of the thyroid hormones. Approximately 85% of circulating T3 is produced by monodeiodination of thyroxine (T4) in tissues such as liver, muscle and kidney.

Selenium and zinc are required for this process.A full assessment of the thyroid should include TSH, FT4, FT3, rT3, urinary iodine and thyroid antibodies. Thyroid-stimulating hormone (TSH) is produced by the pituitary gland and activates the thyroid gland to produce thyroxine (T4) and a small amount of triiodothyronine (T3).

T3 and T4 regulate the body’s basal metabolic rate, influence heart and nervous system functions and are essential for growth and development. The thyroid gland also produces calcitonin which is essential in the regulation of calcium balance within the body.