10 Ways Your Doctor Misdiagnoses Your Thyroid Dysfunction


Have you ever suspected you’ve had an issue with your thyroid? You have all the signs and symptoms, but when you go to your doctor he or she shrugs it off and tells you that it’s “normal” to feel that way. Or maybe your doctor agreed to run lab work on your thyroid but when the results came back they said you were fine and sent you on your way, despite how you were feeling. Thyroid Dysfunction is commonly misdiagnosed because doctors don’t run all of the lab work needed or they interpret the test results with too wide of a reference range. Here’s a scary fact: according to the American Thyroid Association an estimated 20 million Americans have some form of thyroid disease and up to 60% of those with thyroid disease are unaware of their condition. 60%! That’s more than 12 million people who are unaware of their thyroid dysfunction and the reason why they don’t feel optimal.

Thyroid dysfunction can easily be confused with many other conditions such as anxiety, chronic fatigue syndrome, depression, constipation, insomnia, sex hormone issues, and so on because all of these conditions are symptoms of thyroid dysfunction. Which is why it is so important to run thorough functional lab work and use a more specific reference range when treating the thyroid. Even if you’re doctor tells you your thyroid labs are ‘normal’ you may still have thyroid dysfunction, and here’s why:


Your doctor may only test your TSH.

TSH is released by the pituitary and sent to the thyroid. TSH does not tell us how much T4 and T3 the thyroid is releasing, or how much Reverse T3 is in the body. TSH does not tell us if your thyroid hormone is actually entering your cells, which is the deciding factor of how you feel. If you are already taking supplemental thyroid hormone that contains T3 this can suppress TSH and will not give an accurate result.


Your doctor may test your free T4 but not your free T3.

T3 is the active form of thyroid hormone that enters your cells.  If we don’t have a reading of how much free T3 is in your blood we actually we don’t know much at all about your thyroid function.  If we get a reading of free T3 we know if your body is converting T4 to T3 or not.  Without a proper reading we don’t know for sure.


Your doctor may test your total T4 but not your free T4.

Free T4 is what converts into T3. If we don’t know how much free T4 is in your body we don’t know if there is enough to even convert into T3. Bound T4 does not affect your metabolism, so an overall reading of total T4 does not give us enough info to work with. 


Your doctor may test your total T3 but not your free T3.

Similar to the issue above, free T3 is the active form of T3. The form we need to know about, because it affects your metabolism.  So once again, an overall picture of your T3 level does not give us enough information about how the thyroid is functioning.


Your doctor does not test your Reverse T3.

We need to know your level of reverse T3 because too much rT3 lets us know that there isn’t enough room for T3 to enter cells.  Reverse T3 also binds to the receptors in your cells where T3 would attach, leaving less room for T3. Reverse T3 slows down your metabolism. Reverse T3 may be the missing link if all of the rest of your labs look normal.


Your doctor doesn’t test your antibodies.

We need to know your antibody level in order to know whether your thyroid function could be caused by autoimmunity. Diagnosing an autoimmune condition is critical when it comes to treating the thyroid.  The immune system needs to be supported so it stops attacking the thyroid. Plus, thyroid antibodies can be elevated long before your body starts to attack your thyroid, so if caught early enough it can be prevented which is important because thyroid damage can not be reversed.


Your doctor doesn’t test for the necessary nutrients needed for optimal thyroid function.

Your body needs specific nutrients in order to convert T4 into T3.  It also needs specific nutrients in order to have optimal cell health so T3 can enter the cells. Your immune system needs certain nutrients in order to perform optimally.

Iodine and tyrosine are needed to make thyroid hormone. Selenium, zinc and iron are needed to convert T4 into T3. Vitamin D3, B vitamins and Vitamin A are all needed for healthy immune function. Omega-3 fats are needed for optimal cell health so free T3 can enter your cells.


Your doctor doesn’t test your sex hormones and adrenal function.

This is important for several reasons:

  • T3 needs cortisol to in order to pass through the cells.
  • Excess estrogen in the body can cause too much TBG (thyroxine-binding globulin) in your bloodstream. Excess TBG causes T4 and T3 to stay bound resulting in not enough free T4 and free T3.
  • Chronic stress (leading to high cortisol levels) causes the body to stay in fight-or-flight – when the body is worried about surviving it isn’t worried about optimal thyroid function
  • Stress suppresses gut function, leading to leaky gut, which is a major factor in autoimmune conditions
  • Excess cortisol cues the body to slow its production of thyroid hormone
  • Cytokines, inflammatory immune cells, are part of the stress response, and create thyroid hormone resistance

Sex hormones and thyroid function go hand-in-hand, and in order to have optimal thyroid function you need optimal sex hormone levels and vice-versa.


Your doctor does not evaluate your lifestyle.

As I touched on in last week’s blog, there are underlying causes of thyroid dysfunction (you can read more here).  The thyroid just does not stop putting out thyroid hormone or cease to convert T4 to T3 for no reason. Chronic stress is a major underlying cause and deserves to be evaluated.  Your doctor should be addressing your lifestyle – how much stress do you deal with daily? Have you had any major stressful events happen recently? What do you do daily and weekly to de-stress?

What is your nutrition like? Do you have digestive issues? Constipation, gas, diarrhea, bloating, fatigue after eating, and inflammation can all be signs of leaky gut.  Leaky gut can be caused by too much caffeine, alcohol, processed foods, too many antibiotics or prescription medications, etc. and negatively affects your immune system. Insufficient nutrients can be caused by lack of a well-balanced diet, as well as not being able to properly break down and assimilate the nutrients your body needs because of leaky gut.

Your lifestyle plays a key role in optimal health and deserves to be evaluated and prioritized. If your doctor is neglecting this piece it’s time to find a new one or start working with a Functional Diagnostic Nutrition practitioner.


Your doctor uses the general reference ranges, not the optimal ranges.

Reference ranges are too general.  Labs take the results from ALL of the people who have completed the test (despite how they were feeling) and create a reference range based on the average results.  These results DO NOT take into consideration how the patients were feeling – how much energy they had, how well they slept, if they’ve had brain fog, or depression or anxiety, etc. Doctors just want to see you in this reference range. So even if you’re in the reference range, but at the low end it’s “good enough”.  Your lab results may fall within the normal reference range, but that does not mean they are optimal. The optimal ranges are much more narrow than the normal ones.  Any small deviation from the optimal range and you may have negative symptoms.

To summarize what you NEED to have tested in order to know how your thyroid is functioning is:

  • TSH
  • Free T4
  • Free T3
  • Reverse T3
  • Thyroid Peroxidase Antibodies (TPO)
  • Thyroglobulin Antibodies (TgAb)
  • Iron/Ferritin
  • Vitamin D
  • Vitamin A
  • Homocysteine
  • Selenium
  • Zinc
  • Magnesium

If you are interesting in having thorough lab work ran to get to the root cause of your thyroid issue or having your lab results analyzed by a Functional Diagnostic Nutrition Practitioner contact Veronica at veronica@veronicamcnelis.com