Are you a questioner? Do you like to know the why behind things? Do you feel like you need more information before you buy in? Sometimes I do and sometimes I don’t but when it comes to my health, I definitely do! I need the what, when, how and why! Getting more information through thyroid lab testing is a great example of how we can answer some of the “why’s” you might be asking. Why do I continue to have symptoms even though my TSH is normal? Why does my doctor refuse to run any additional lab tests? Why do I continue to feel like this when I am being treated for my condition? Why do I continue to feel like it’s a thyroid problem but my doctor keeps dismissing me? Why, why, why?
One of the biggest challenges in determining what is actually happening with the thyroid gland and other systems involved with thyroid hormones is the ability to get the proper labs completed. Thyroid health is an area where we really need to look at the big picture and how all of the little pieces work together. Research shows that about 5% of the US population has thyroid dysfunction and about another 5% are undiagnosed. That is 5 of every 100 people that don’t know they have a thyroid problem.
Many conventional doctors, where most of us go for routine visits, base a thyroid diagnosis on a TSH level and sometimes also a total T4. These labs are how they diagnose and decide on treatment with medications, typically Synthroid, a T4 only med. Let’s be fair, though, it is what they know and how they were trained and we can’t expect them to be thyroid experts. Oh, and they also use outdated conventional reference ranges for the labs. It’s no wonder why so many of us are misdiagnosed or undiagnosed and dismissed with continued nagging symptoms. We need to be our own advocates and keep asking “why?” I typically recommend working with a functional medicine practitioner if you can as they take a different approach to your health. They will want to do additional testing and use functional ranges to get more information on why you continue to have problems.
I’ll share with you a client story. A recent client, let’s call her Lucy, came to me with Hashimoto’s and hypothyroidism. Lucy’s symptoms include fatigue, weight loss resistance, irregular and painful periods, low libido and anxiety. Symptoms that have not improved even though she is being treated for her condition under a physician’s care. The previous labs she sent included a TSH and a free T4 and she is on Synthroid, a T4 only hormone medication. Her TSH is functionally low at <0.5 and her Free T4 is slightly high most likely due to too much Synthroid. What we don’t know is her Free T3, which is the active thyroid hormone that is going to help control all the things that cause her symptoms. Does she have enough T3? Is T4 appropriately being converted to T3? Is too much T4 converting to reverse T3 causing a halt in thyroid hormone function? What are her antibodies? Is her immune system attacking her thyroid? Holy unanswered questions Batman! This is why I want to see the full panel. You get me?
Knowing these answers will help me help Lucy. If we are looking at an immune system issue, I want to work through diet and lifestyle factors that can make a difference with autoimmune thyroid disease. If there is a problem converting T4 to T3, we can look at ways to optimize it and things that can be hindering the conversion. Do we need to go back to the doctor to try a T3 hormone supplement as well?
In this blog post, we will talk about how the thyroid works, who should be tested for thyroid disorders, why you should get a thyroid panel run, and the tests in a thyroid panel including functional ranges.
How Does the Thyroid Gland Work?
The thyroid gland is a butterfly-shaped gland located at the front of the neck below the Adam’s apple. It works in a feedback loop with the hypothalamus and pituitary gland to produce thyroid hormones. The hypothalamus produces TRH, or thyrotropin-releasing hormone, which stimulates the pituitary gland to produce TSH, or thyroid-stimulating hormone, which stimulates the thyroid gland to produce T4, T3, and calcitonin.
T4, or thyroxine, and T3, or triiodothyronine, are thyroid hormones produced by the thyroid gland. They are what control the body’s metabolism, body temperature, and many other functions. T4 is produced in about 4x the amount of T3 but T3 is about 10x as active in the body as T4. Most of our T3 needs to be converted from T4 primarily in the liver and kidney.
Here is how the thyroid should work: when there is too much thyroid hormone (T4 and T3) circulating in the body, TSH is decreased and thyroid function decreases in order to stop producing hormones. When there is too little thyroid hormone circulating in the body, TSH is increased in order to increase thyroid function and produce more hormones. There should always be adequate amounts of hormones circulating to be used by cells in the body.
Who should be tested for thyroid disorders?
According to the American Thyroid Association, anyone age 35 and over should be tested for thyroid disorders and then retested every 5 years after that if within normal ranges. I would absolutely argue that women need to be tested before age 35 and at least every year. The age really depends on symptoms, if you’re having trouble conceiving, and other factors. Thyroid disorders don’t discriminate based on age. You should absolutely be tested if you have multiple symptoms of a thyroid disorder or a family history. Symptoms of hypothyroidism and Hashimoto’s include:
Dry, brittle hair
Sensitivity to cold
Irregular menstrual cycles
Muscle fatigue and weakness
If you are experiencing 2 or more of these symptoms and aren’t sure if they could be thyroid related, I would encourage you to get tested. Otherwise, you might be treated for the individual symptom(s) that may not improve if it’s related to your thyroid but the thyroid is not addressed.
Why Run a Thyroid Panel
More information can be very helpful when looking at the thyroid and the typical symptoms of a thyroid problem. Remember that we want to know why! Thyroid testing is a controversial subject where some don’t believe that running a full thyroid panel is useful in the treatment of thyroid disorders. I disagree. I believe in running the full thyroid panel as it can show that problems don’t always just come from the thyroid. The tests can provide information on where there is a break in the chain of events that leads to adequate thyroid hormones being produced and used appropriately. A break in that chain can equal symptoms that won’t go away. Testing only a TSH and T4 can lead to misdiagnosis when we can’t see the other pieces of the chain.
I also believe in testing thyroid antibodies as over 90% of hypothyroid cases are due to the autoimmune disease, Hashimoto’s. It is important to know if you have an autoimmune disease because if you have one you are at a much higher risk of having another and some autoimmune diseases can go hand in hand. You better believe I would want to know if I am at a higher risk of my body continuing to attack itself in different ways and if there is something I can do to prevent that! Doctors don’t often run them because it doesn’t change their treatment plan. Do you need to run antibodies every time you do thyroid labs? No. Antibodies don’t typically change quickly, but having them tested occasionally is a good idea, especially if you are working on supporting your immune system and bringing them down. Then, you will know if your efforts are paying off or if you need to try something different.
Tests included in a Thyroid Panel
TSH (1-2 mU/L) - Thyroid-stimulating hormone, produced by the pituitary gland, stimulates the thyroid to produce more hormones when there aren’t enough circulating in the body. TSH is increased when there aren’t enough thyroid hormones circulating as it is trying to signal the thyroid to produce more. It is suppressed when there is too much hormone circulating as it doesn’t need to stimulate the thyroid to produce more hormone at that time. This is the most common thyroid lab tested and often what diagnosis and treatment is based on. A TSH alone is not an adequate marker of thyroid function.
Free T4 (1.1-1.8 ng/dL) - T4, or thyroxine, is a hormone produced by the thyroid gland. The thyroid gland produces T4 and T3 but T4 is produced in a much greater amount. Free T4 is not bound to a protein and is able to be used in the body. T4 must be converted to T3, the more active thyroid hormone, so it is important to know if the thyroid is producing enough T4.
Free T3 (3.2-4.2 pg/mL)- T3, or triiodothyronine, is a hormone produced by the thyroid gland. There is a very small amount produced by the thyroid and the rest needs to be converted from T4 in the liver and gut. T3 is the main active hormone and free T3 is not bound to a protein and able to be used in the body. If the T3 level is inadequate, there will still be thyroid symptoms.
Reverse T3 (10-15 ug/dl or <10:1 ratio of RT3:FT3)- This is the opposite of free T3. Reverse T3 is the inactive thyroid hormone that blocks thyroid receptors and can put the brakes on thyroid hormone functions. Some T4 can be converted to reverse T3 in the liver. This is often seen with illness, increased stress and cortisol, and fasting.
TPO and Tg antibodies (<4 or negative) - when antibodies are present, this can suggest an autoimmune thyroid disease (discuss with your physician). Antibodies are proteins produced by the immune system to attack against what it thinks are invaders. This blog post will give you more information about testing for antibodies. Many doctors won’t test as it doesn’t change their treatment plan.
I hope this helps to clear up the importance of getting a full thyroid panel run in order to see all components involved in thyroid health. You don’t have to continue to live with life-affecting symptoms because you aren’t getting the care and treatment you need and deserve. I always recommend discussing these labs with your doctor. You can check with them and your insurance about the cost. Also, don’t be afraid to get a 2nd opinion if your doctor won’t work with you. Be sure to scroll back up and get my free thyroid testing guide, if you didn’t already, to have access to information about these labs and the functional ranges.