The most important thyroid tests and what your doctor isn't telling you
Updated: May 11
In conventional medicine, doctors only test for TSH levels, and some T4 levels, when checking your thyroid health. Unfortunately, this way of testing is massively flawed. These are the reasons why:
1. TSH stands for Thyroid-stimulating hormone. This hormone is made from the pituitary gland in the brain where it acts as a messenger to the thyroid gland to produce thyroid hormones. However, the BIGGEST issue with looking at TSH only when measuring the health of the thyroid, is that is is a hormone produced in the brain, not the thyroid. Therefore, whatever happens once that message has been sent can be overlooked. It is like sending an email to somebody with an urgent and highly important job to do, and then just taking the act of you sending the email to be evidence that the job has actually been done. But actually, there could be a whole number of issues as to why the job might have not been done, including the fact that the email may not have been received properly due to a server issue, maybe the internet was down, maybe there was a power cut, etc. That’s not to mention all the other reasons such as the person you sent it to wasn’t feeling very well and so went home and therefore never got to read your email, or perhaps they saw your email, but had too much on their list to do that day that they couldn’t fit it in. The act of you just assuming that it would get done without any other communication with them is the same as looking at a ‘within-range’ TSH level and then claiming that the thyroid function is fine. Solely looking at the level of a hormone produced in the brain cannot tell us if the thyroid is functioning properly.
2. This then leads me on to the hormones that the thyroid gland actually produces. The thyroid gland produces mainly thyroxine (T4), and a small amount of triiodothyronine (T3). T3 is the most active form of thyroid hormone (300 percent more biologically active than T4). Being ‘active’ just means that the body can actually USE the hormone in this state. If it is ‘inactive’ then it is useless.
‘Most scientists agree in defining T4 more like a “prohormone” rather than a real hormone, although it is the major hormone secreted by the thyroid. . T4, in fact, is not very active; it expresses the functional activity of the gland, but to be useful to the human body it must be converted to T3.’ (Nordic and Basciani, 2017)
Most of the T4 that the thyroid produces gets converted to T3 in the body. However, many people can have issues with converting T4 into T3 and therefore this can be a reason why measuring only TSH or T4 does not give a true representation of thyroid hormone levels. It’s no use having lots of ‘inactive’ thyroid hormone which cannot be utilised by the body. You might as well not be producing any thyroid hormones if they are not ‘active’. This underlines the importance of having your T3 levels checked, as well as your T4.
3. In addition to having problems converting T4 to T3, another issue that measuring only TSH and T4 levels will not pick up, is if you have high levels of Reverse T3. Reverse T3 is a hormone which is created in periods of stress or due to inflammation and infection. It is a completely inactive hormone, that doesn’t do anything but take up the space on the receptor sites made for T3 to bind to. It essentially blocks the active T3 hormones as it has already taken it space, and then does absolutely nothing! This is why it is a good idea to get Free T3 levels tested, as well as Reverse T3 levels.
4. It doesn't test whether your thyroid disease is a result of an autoimmune problem - which would then suggest that there are further complications going on within your body that need to be addressed.
What are the most important thyroid tests?
You need to do a full thyroid panel of testing before anyone can even make a judgment about your thyroid and treatment plans etc. These tests are:
Reverse T3 (optional)
Many thyroid patients are misdiagnosed by clinicians who don’t take into account all the above tests. Or they may diagnose a patient with hypothyroidism from looking at TSH levels only, but then not even think about checking antibodies to see if it is autoimmune! Which is crazy considering that they are now saying approx. 90% of hypothyroid cases in the USA and UK are caused by Hashimoto’s.
How do I know if my thyroid problem is autoimmune?
In order to find out whether your hypothyroidism is autoimmune you need to get your thyroid antibodies tested. These are TPO antibodies and thyroglobulin antibodies which are elevated in the case of Hashimoto’s. It is possible to have just one type elevated, or both. In most cases, both are elevated. The biggest issue with doctors just testing TSH or T4 is that it won't pick up whether your thyroid problem is autoimmune. So the question you're probably asking is: What is the issue with not knowing whether you have an auto-immune disease? And the answer is that the supplemental thyroid hormone that you are given to 'treat' hypothyroidism (such as Levothyroxine) is NOT going to solve the autoimmune issue. The autoimmune component causes inflammation in the body, causes serious side effects and if left untreated can lead to developing other autoimmune diseases, heart problems or strokes just to name a few. It is so important that we take the necessary steps to reduce antibodies and inflammation in the body.
How do I reduce inflammation in the body and reduce antibodies?
Check out my blog on this subject here: https://www.mythyroidlove.com/post/how-to-reduce-inflammation-and-thyroid-antibodies