Thyroid Function Testing
What is the thyroid
The thyroid is a butterfly-shaped gland that is found in the neck, just below the Adam’s apple. It is one of the largest hormone-producing glands and it is essential for healthy function of the entire body. The thyroid controls how quickly the body uses energy, makes proteins, and it controls how sensitive the body should be to other hormones.
The thyroid gland produces thyroid hormones, known as triiodothyronine (T3) and thyroxine (T4). These hormones regulate your metabolic rate and affect the growth and rate of function of many other body systems.
A number of nutrients are essential for making T3 and T4 including:
- iodine
- tyrosine
- zinc
- selenium
The thyroid gland also produces another hormone called calcitonin, which is important in helping to regulate calcium levels in the body.
The thyroid gland is controlled by the production of thyroid-stimulating hormone (TSH), which is produced by the pituitary gland, as well as thyrotropin-releasing hormone (TRH) produced by the hypothalamus.
Common thyroid problems
The most common problems of the thyroid gland are when it becomes underactive – known as hypothyroidism or when it becomes overactive, known as hyperthyroidism.
Hypothyroidism is the most common thyroid problem. It occurs when the thyroid gland does not produce enough thyroid hormones, as a result of iodine deficiency (an increasing problem in Australia) or autoimmune disorders such as Hashimoto’s thyroiditis, where an abnormal immune response causes the immune system to attack thyroid tissue.
Typical symptoms of an underactive thyroid include:
- weight gain
- fatigue
- thinning hair
- cold intolerance
- lowered heart rate (bradycardia)
- hormonal problems
- depression
- increased cholesterol
Hyperthyroidism is an overactive thyroid which occurs when the thyroid gland produces too much of the thyroid hormones T3 and T4. The most common cause is Graves Disease, which is an autoimmune disease where antibodies are produced that stimulate the thyroid to secrete excessive quantities of thyroid hormones. Hyperthyroidism can cause a goiter to form, where the thyroid enlarges and/or produces nodules in response the excessive stimulation.
Typical symptoms of an overactive thyroid include:
- weight loss
- palpitations
- loose stools
- sweating
protruding eyes (exopthalmos) - unusual heat sensitivity
- muscle weakness
- anxiety
- fatigue
How to test for thyroid problems
A full thyroid function test is the best way to assess how well your thyroid is functioning.
At Remède, our practitioners go beyond the basic thyroid testing of TSH that is most commonly performed medically – which often misses important thyroid markers. You may be told that your thyroid function is normal when TSH levels are within an acceptable range. However, having normal TSH levels does not automatically rule out an underactive thyroid.
If you suspect you have a sluggish or underactive thyroid, our practitioners will perform a full thyroid function testing, which includes TSH plus T3, T4 and thyroid antibodies as indicated. This will assist an accurate diagnosis of actual thyroid function.
The reason why a single test of TSH is not an accurate measure of thyroid function, is because it does not reflect how much T4 and T3 is actually being produced bt the thyroid gland. In addition, it does not assess how well T4 is converting into T3 – which is the active thyroid hormone. In fact, it may not be converting at all, it may be converting to the inactive form of T3 called reverse T3 (rT3) – which is an inactive form of T3 that is not tested for in standard thyroid tests.
Our practitioners can test for reverse T3 (rT3), which often occurs in “sub-clinical hypothyroidism” which occurs when T4 converts to rT3, instead of active T3 – and it causes all of the symptoms of hypothyroidism. Reverse T3 is produced in higher amounts during periods of stress, in response to toxicity and if you are deficinet in essential nutrients such as selenium, zinc and tyrosine. A measurement of rT3 is valuable in identifying a condition called Reverse T3 Dominance.
In addition to blood testing, your practitioner may also ask you to take your basal body temperatures, as part of the overall thyroid assessment.
If low thyroid function is suspected, your practitioner may also order a urinary iodine test.
This thorough and comprehensive approach means that those patients who suspect they have a thyroid problem or those who have been suffering from undiagnosed symptoms for some time, are properly diagnosed and then treated using a holistic and effective approach that takes all factors into consideration.