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What you need to know about thyroid testing.


The thyroid gland and it’s hormones have widespread action within the body.  The hormones produced by the gland are responsible for regulation of the body’s energy metabolism.  The thyroid gland has actions on the neurological, cardiovascular, musculoskeletal and reproductive systems.

Thyroid laboratory testing is common as part of annual physical, or is ordered when symptoms of thyroid dysfunction are presenting.  In many cases only the measure that is tested is TSH, while this is a starting point, having a full thyroid panel will tell you so much more.

TSH (Thyroid Stimulating Hormone) – this hormone is actually produced in the pituitary gland in the brain and is responsible for growth of they thyroid gland. TSH works a negative feedback loop – meaning the more T4 (thyroid hormone) produced the less the TSH is produced.

In cases of hypothyroidism (low functioning thyroid), TSH typically elevates, and in hyperthyroidism (over functioning thyroid) TSH becomes depressed.

T4 (thyroxine)- is the produced in the thyroid gland and is considered a prohormone for T3.  T4 has very little function on the cells of the body.

In cases of hypothyroidism T4 (levothyroxine – trade names — synthroid, eltroxin) are the standard treatment.

T3 (triiodothyronine) – is the thyroid hormone that has action on the cells of the body, it is made from the conversion for T4 to T3. This conversion process relies on a number of body systems and cofactors.

The liver, gut and adrenal glands are all organs that play a role conversion of thyroid hormones, so if there is any dysfunction within these systems conversion may be inadequate.

Thyroid antibodies – Thyroid peroxidase antibody (TPOAb) and Thyroglobulin antibody (TgAb) – The top cause of hypothyroidism in North America is result of Hashimoto’s Thyroiditis, which is an autoimmune condition, meaning an individuals immune system is attacking the thyroid gland, and decreasing its function.

Autoimmune conditions respond very well to diet and lifestyle changes, specifically elimination of food sensitivities.

Reverse T3 (rT3) – this form of T3 is biologically inactive, and is typically formed when the body is under periods of extreme stress or chronic illness.  Although, this test is not often tested, when it is found to be elevated it gives practitioners an understanding that more then just the thyroid gland needs to be supported.

Registered Naturopathic Doctors in Ontario are able to run all of the above listed tests.  Contact me if you have any questions about getting your thyroid health evaluated.


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