When a patient presents with thyroid symptoms in our conventional medical system, their doctor will usually only order a TSH blood test. If they’re lucky, they may also receive a T4 or FT4 test, but these tests do not tell the whole picture. Having a full thyroid panel run could save you years of wasted money and increasingly miserable thyroid symptoms.
Did you know that the TSH test doesn’t even actually measure anything coming from the thyroid gland itself? Instead, it measures the amount of Thyroid Stimulating Hormone being released from the pituitary. TSH, in turn, stimulates the thyroid to release thyroid hormones. So in essence, a TSH test is actually measuring the pituitary and the state of the feedback loop know as the hypothalamic-pituitary-thyroid axis.
Many patients have reported that they were suffering from thyroid symptoms for years before the TSH test finally came back with an abnormal result. You and your doctor should always listen to your symptoms first and foremost and then use a full thyroid panel (see chart below) to help fill in the pieces. The TSH test will never give you the full story.
If you are already on thyroid medication, including natural desiccated thyroid hormone, you should only be using FT3 and FT4 to help fine-tune your dosage. Often TSH levels will decrease during this time and doctors may erroneously assume you are entering a hyperthyroid state. Pay close attention to your symptoms and monitor your FT4 and FT3 to find your optimal dose.
If you want to test the function of your thyroid then the best lab tests to run would be those that test the amount of thyroid hormone actually being released from your thyroid gland. The two main players are T4 and T3. More specifically, you want to test the Free T3 (FT3) and Free T4 (FT4) levels which measure the unbound hormone in your system.
T4 is the storage form of thyroid hormone while T3 is the active form. Every cell in our body has receptors for thyroid hormone. We need enough T4 to be available so it can convert into T3 when we need to energize that cell. Measuring the free forms of each of these hormones shows us how much is available to be used.
When a patient is found to have a high TSH (which means their thyroid is under-performing and therefore, hypothyroid), they are often prescribed Synthroid or the generic form, Levothyroxine which is a synthetic T4 only hormone. In fact, it is one of the top selling drugs in the United States. This is all well and good if the FT4 is indeed low, but this test is often not run. Even then, you are only getting half the picture without also testing the levels of FT3. If FT3 is also low, then that means you aren’t converting the T4 into T3 and therefore your cells are not getting the gas needed to turn them on.
This is exactly what happened to me. I was treated with just Levothyroxine for 10 years, as a result of only being tested for TSH. My doctor told me I would need to be on the hormone for the rest of my life so I just did what she told me. Over time all of my symptoms got worse and worse, yet my TSH remained the same and therefore so did my prescription for Levothyroxine.
It wasn’t until I became my own advocate, and demanded (yes, demanded, because they didn’t want to allow me) that they run all of the tests in the chart below. All this time, it wasn’t a T4 problem I was having, it was a conversion problem. I wasn’t making enough T3, so adding synthetic T4 only for 10 years did absolutely nothing for me. I was so frustrated that my doctor never ran a complete thyroid panel from the beginning which could have saved me 10 years of further suffering, not to mention hundreds of dollars in prescription costs. I now remain on a small dose of a combination hormone which includes T4 and T3 and I feel so much better. Please do not make the same mistake, and get a full thyroid panel so you know the whole picture and can treat yourself accordingly.
Print out this list and bring it to your doctor at your next appointment. If they do not want to run all of the tests, I would encourage you to find a doctor who will, or else you can order them yourself from labs such as Ulta Lab Tests or Direct Labs. Please check with your insurance company ahead of time if you can submit the bill for reimbursement.
Also, please note that certain supplements like biotin and iron will alter the results of these tests. It is best to refrain from all supplements for a period of time before your lab tests and also hold off on your thyroid medication the morning of your blood draw.
As you can see, there are some other recommended tests in this chart we have not discussed such as RT3. Reverse T3, or RT3, is a controversial test among physicians as some do not see any point to it and others find it essential. Not only can T4 convert into T3, but it also can convert into RT3, the inactive form of T3. RT3 binds to thyroid receptor sites, blocking T3 from attaching to those sites. An excess amount of RT3 is often produced during times of stress when the body needs to conserve energy. You can hold off on this test until after receiving your FT4 and FT3 tests. If you have a high FT4 or a very low or high FT3, then you may want get the RT3 checked.
The other big piece of this puzzle, is the autoimmune element. The antibody tests in the chart above are essential to determining if you are experiencing an autoimmune attack on your thyroid which is causing you to either become hypo- or hyperthyroid. The two autoimmune thyroid diseases are Graves’ Disease and Hashimoto’s Thyroiditis. You can read more about Hashimoto’s in my previous post HERE. Essentially, Grave’s disease causes the thyroid to produce too much thyroid hormone, leading to hyperthyroidism, while Hashimoto’s causes the thyroid to produce too little thyroid hormone, leading to hypothyroidism.
Now that you have received all of the proper tests, what do they all mean? In the chart below, you will notice lab reference ranges versus optimal functional ranges. Lab ranges provided by the testing company are often very broad. Optimal ranges are much tighter and are where the majority of patients feel their best. These are just a guideline however. Please work alongside your physician to analyze your results and determine what is the best course of action for you.
If your antibodies have come back negative and you are still suffering from thyroid symptoms, you may want to ask for an ultrasound of your thyroid. This will show if there have been any changes to your thyroid tissue and/or if any nodules have formed.
The most important diagnostic tool, along with all of these lab tests, are your symptoms. Make a list of them and bring them to your doctor. The lab tests above will help to corroborate your symptoms and can be used when adjusting any medication that may be needed. Otherwise, your treatment should always proceed with your symptoms being the main gauge.
Receiving a full thyroid panel gives you a clearer picture as to the functioning of your thyroid gland, but it is just the beginning. Your thyroid didn’t just start malfunctioning out of the blue. You will need to now uncover the root cause as to why it is malfunctioning. Taking care of the root cause is the key to eliminating your symptoms. Stay tuned for a future blog post which will address potential root causes.
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