The thyroid gland is a butterfly-shaped organ located at the front of your neck. It is a vital hormone gland that plays a major role in metabolism by constantly releasing a steady amount of thyroid hormones into the bloodstream. If you are experiencing low energy, depression, anxiety, irritability, nervousness, insomnia, poor memory, weight gain, high cholesterol, dry skin, constipation, heart palpitations, or low motivation or ambition, among the first things to check is your thyroid function.
Most people who come to see me generally do not come specifically for treatment of their thyroid. They usually come with a pre-diagnosed thyroid condition, mostly low thyroid (hypothyroid), for which they were prescribed thyroxin, such as Synthroid or Levothyroxin, or in a very small number of cases natural, porcine derived, desiccated thyroid. Naturopathic physicians with pharmaceutical prescriptive authority are authorized to prescribe thyroid hormone replacement. My preference is to always look for and treat the underlying causes of thyroid disorders before prescribing thyroid hormone replacement medication as a last resort.
The types of thyroid disorders that I commonly encounter range from an underactive thyroid (hypothyroid) to an overactive thyroid (hyperthyroid), some have hypertrophy, or enlargement of the thyroid gland, and others have thyroid lesions or nodules. Some started out with a thyroid that was initially underactive and then became overactive and vice versa. Some started out with an overactive thyroid which was treated with radioactive iodine to destroy a part of the thyroid gland to make it less overactive. Radioiodine is meant to shrink an overactive thyroid gland by destroying it in part or entirely, which can turn an overactive thyroid into an underactive thyroid, requiring thyroid medication for life.
It has been my general observation that most people who start on low dose thyroid hormone replacement tend to need increasing doses of medication, since thyroid function usually worsens, rather than improves with time, unless the underlying causes are addressed. In my experience, thyroid problems that are caught early are much easier to manage and reverse. It becomes very difficult and may not be possible to reverse a thyroid disorder that has gone on for too long without the underlying causes being addressed.
How can you check your thyroid function?
The most basic screening test for thyroid function done by doctors is a blood test called Thyroid Stimulating Hormone, or TSH. Thyroid stimulating hormone is not a thyroid hormone at all. It is a hormone made in the pituitary gland of the brain. It seems odd that we test thyroid function by testing a hormone made by another gland located elsewhere from the thyroid.
The pituitary gland regulates the thyroid gland. The pituitary gland is like a thermostat in your bedroom telling your furnace (thyroid) when to turn on and off. If your bedroom is cold, the thermostat sends signals to the furnace to turn on and do its thing, which is to generate heat. When your bedroom gets warm, the thermostat sends signals to the furnace to turn off. The thermostat regulates the on and off switch of the furnace. If the thermostat is working properly, the bedroom will get neither too cold nor too hot. The pituitary gland acts as a thermostat that senses when the thyroid gland needs to make thyroid hormones and when to stop making thyroid hormones. If the pituitary gland is working properly, the thyroid gland will work properly as well, always producing not too little and not too much thyroid hormones.
What are the thyroid hormones?
We said that the most basic screening test for thyroid function is a pituitary hormone called Thyroid Stimulating Hormone or TSH. TSH stimulates the thyroid gland to produce thyroid hormones. The two main thyroid hormones made by the thyroid gland are thyroxin (T4) and triiodothyronine (T3). Why measure a pituitary hormone to find out how the thyroid is working? Wouldn’t it be better to measure the thyroid hormones directly?
The reason for using a pituitary hormone as a surrogate marker for thyroid hormones instead of testing the thyroid hormones directly has to do primarily with cost and expedience. It’s like checking your thermostat in your bedroom to see how well your furnace is working. It’s easier to just look at the thermostat rather than go all the way down to the basement to check to see if the furnace is working. Most of the time we can tell from looking at the thermostat to see if the furnace is working or not. Likewise, most of the time the TSH is a reliable indicator of thyroid function. The current standard of care screening test for thyroid function in conventional medicine is TSH because it is a less expensive and more convenient test than testing the thyroid hormones directly.
But what if the thermostat isn’t working properly? We would then have to go all the way down to the furnace to check and see if it is working properly. It is always better to check the actual thyroid hormones, just like checking the furnace instead of the thermostat to see how well the furnace is working. The thermostat is not a diagnostic motherboard for the furnace. It is just an on and off switch. It’s all good if the bedroom is the right temperature. However, if the thermostat seems fine, but your bedroom is either freezing or feels like a sauna, you will have to make the trip to the basement to check the furnace directly. I have seen many people whose TSH was within the normal range but who had all the classic symptoms of an underactive, and in some cases overactive thyroid. Sometimes the thermostat can fail. The pituitary gland may not be able to produce enough TSH to stimulate the thyroid gland. Pituitary failure can cause low thyroid function just like a faulty thermostat can turn off the furnace. This is called secondary hypothyroidism and it can be missed if we rely solely on the TSH.
To summarize, the reason the TSH is the preferred standard test for thyroid function has to do with cost and convenience, not because it is a more specific or better test. The thyroxine (T4) and triiodthyronine (T3) are more precise tests for measuring thyroid function than the TSH. If your TSH is within the normal reference range you will usually not be able to get T4 and T3 done. Even if your family doctor requests that you have a full thyroid panel done, LifeLabs can reject the T4 and T3, even if your doctor has specifically checked them off on your requisition. Only if the TSH is outside the normal reference range is the lab authorized to test T4 and T3.
The problem with the standard reference range for TSH it is can be too wide for some people. Too many hypothyroid cases can be missed if they happen to fall in the higher end of a reference range that many experts consider as too high. If your TSH is borderline high, and you have the classic symptoms of low thyroid, you want to make sure that you don’t fall through the cracks. If you want to know what your thyroid hormone levels are, you may, unfortunately, have to pay for the tests out-of-pocket. In certain circumstances your family doctor or specialist may be able to get your thyroid hormones tested, but this is more often the exception rather than the rule if your TSH is within the standard reference range. Doctors aren’t the ones to blame because the lab is required to follow guidelines. These guidelines are in place to reduce costs to the public health system. Your personal, individual health is not enshrined in the mission statement of the guidelines. If you want optimal health and you don’t want to fall through the cracks, you sometimes may need more than what is provided by the system. In other words, sometimes you may have to take matters into your own hands.
Summary of tests to properly check your thyroid.
The first test is still TSH. You have to have your TSH done even if you get your T4 and T3 done. They should be done together for proper interpretation of thyroid function.
The T4 thyroxin test that you need is called Free T4 or FT4. The Free T4 is a more specific test than Total T4. The T3 triiodothyronine test that you need is called Free T3 or FT3. Free means that the hormone is free in the blood and not bound to anything else that would make it inactive. The Free T3 is the most important thyroid test of all because it measures the active thyroid hormone that governs thyroid function and the metabolic rate of every cell in your body. If your Free T3 is low, you will have low thyroid function, even if your TSH, Total T4, and Free T4 are all within normal limits.
I have heard of many cases where patients were told that the TSH accurately reflects the T3, and that it is therefore not necessary to test T3. I have personally seen enough cases over the years to know that this is not always true.
So far, we have discussed the TSH, Free T4, and Free T3. But there is more to it. You may still be experiencing thyroid dysfunction even if your thyroid hormones are all in the normal range. It is possible to have an autoimmune condition where your immune system is making antibodies that are damaging the thyroid gland or interfering with the thyroid receptors on your cells. The tests that rule out autoimmune thyroid problems such as Hashimoto’s Disease or Graves’ Disease are Thyroperoxidase Antibodies and Thyroglobulin Antibodies. If either one or both of these are high, your immune system is making antibodies that can be damaging your thyroid.
But there is more. What if you are under prolonged chronic stress and you have an overactive sympathetic nervous system with elevated catecholamines and cortisol? You may have high reverse T3. Reverse T3 is a mirror image of regular T3. They are identical hormones. Just like a left and right glove. They are the same but don’t fit on both hands. Reverse T3 will not fit on the T3 receptors and will act as a blank or inactive hormone, like a dud hormone. If your reverse T3 is high, you will be hypothyroid, despite all your thyroid hormones falling within the normal reference range.
So, if you have a TSH test from your doctor that is within the normal reference range, and you suspect that you may still have low thyroid function, there are two LifeLabs panels that can be done privately through our clinic.
LifeLabs Thyroid Assessment Basic includes the following blood tests:
TSH (Standard screening test done by doctors. Measures a pituitary hormone, not thyroid hormones)
Free T4 (Only done if TSH is outside reference range. Measures inactive thyroid hormone thyroxin)
Free T3 (Only done if TSH is outside reference range. Measures active thyroid hormone triiodothyronine and is therefore the most important test for thyroid function)
Antithyroperoxidase Antibodies (Most common immunoglobulins that attack/damage/destroy the thyroid gland)
LifeLabs Thyroid Assessment Enhanced includes the following blood tests:
TSH (Standard screening test done by doctors. Measures a pituitary hormone, not thyroid hormones)
Free T4 (Only done if TSH is outside reference range. Measures inactive thyroid hormone thyroxin)
Free T3 (Only done if TSH is outside reference range. Measures active thyroid hormone triiodothyronine and is therefore the most important test for thyroid function)
Reverse T3 (Measures inactive T3 which impairs thyroid function. You will have low thyroid function if this test is high)
Antithyroperoxidase Antibodies (Most common immunoglobulins that attack/damage/destroy the thyroid gland)
Antithyroglobulin Antibodies (Less common immunoglobulins that attack/damage/destroy the thyroid gland)
For further information and costs of these tests, or if you need help in interpreting your existing thyroid tests please call or email our clinic.
-From the desk of Dr.Brkich