This is the second in a series of posts about thyroid health. In our first post of the series, I discussed how the thyroid works and the symptoms of the most common thyroid disorders. If you haven’t read it, you can find it here.
Now that you know what the thyroid does and what symptoms to look for, I want to give you the scoop on testing. Before we do that, however, I think it’s important to understand some of the physiology of your body and how the thyroid gland makes hormones, so you have a better understanding about why certain labs are needed.
The thyroid is controlled by two very important glands in the brain, the hypothalamus, and the pituitary gland. These glands are considered master regulators of your endocrine system and are in charge of helping your thyroid gland produce the hormones it needs to function properly.
The pituitary gland makes a hormone called TSH, or thyroid stimulating hormone. The secretion of TSH alerts the thyroid to produce T4. Once T4 is released, it is converted into T3, the active form of thyroid hormone, by the liver.
For proper biological functioning, all of these steps have to occur. If the brain, pituitary gland, thyroid, and liver are not able to work in conjunction with each other, you could end up with a thyroid disorder. We’ll dive into this a bit more as well as other causes of thyroid disorders in our next blog post of the series.
If you suspect that you have a thyroid issue, it’s important to have your thyroid hormone levels checked. Proper testing of the thyroid will include the levels of TSH, free T4 and T3 – free T3 and T4 are the biologically active forms of thyroid hormone.
Your healthcare practitioner will look for a TSH level of 0.4 – 4. This is the normal range according to most traditional doctors and labs, but what I see more frequently in my practice is patients with a TSH level higher than 2 tend to be experiencing symptoms of hypothyroidism. The higher your TSH levels, the harder your thyroid is working, so the range that is ideal for most people I see in my practice is 1.5 – 2.
Similarly, free T4 levels are best between 1 and 1.5, and since T3 is responsible for activating metabolism and carrying out proper functioning of the thyroid, 3 – 3.5 is the range I look for most frequently when assessing patients’ blood work. When patients are within these ranges, they rarely experience thyroid disorder symptoms.
In addition to having your levels of TSH, free T4 and T3 tested. It is also important that your healthcare practitioner test for Hashimoto’s and/or Graves’ disease. Both of these are autoimmune disorders involving the thyroid, causing hypothyroidism and hyperthyroidism respectively. Like other autoimmune disorders, they cause your body to create antibodies that attack itself – in this case, the antibodies target the thyroid gland, inhibiting it from functioning properly. To test for Hashimoto’s or Graves’ disease, your doctor may order 2 tests – microsomal TPO and a thyroglobulin antibody test.
If you are experiencing symptoms that look like those associated with a thyroid disorder, find a healthcare practitioner that is willing to order comprehensive testing of all of the hormones listed above as well as reverse T3 – this indicates how much T3 is being stored in your body and is another important marker to have when assessing thyroid function.
Have your doctor look at the results of your blood work in relation to your symptoms and be sure that they are willing to work with you and the unique needs of your body.