Issue #215 June 30, 2014
Welcome to KnowYourThyroid.
Today, we are discussing thyroid testing. The #1 complaint I hear is that doctors will only run a TSH test when measuring thyroid function. The result is usually “your thyroid hormone levels are within the normal range” so you need a diet program or here is a prescription for antidepressants or you need to exercise more and that will help ease your symptoms. Not So Much! The other issue is the medication you are prescribed if you are hypothyroid, the majority of doctors will only prescribe Synthroid to treat hypothyroidism, does not work very well for many people. Dr. Marchegiani will explain why doctors think the way they do and why it is so difficult to receive the proper treatment.
Difficulty losing weight
Cold all the time
Chronic Fatigue Syndrome
Diffuse hair loss or dry hair
Cold extremities (editor: in other words, a cold butt!)
Shortness of breath
Heavy menstrual flow
Muscle or joint aches
If you have two or more of the above symptoms and your doctor is telling you you’re fine, then this article is for you!
Why running your TSH isn’t enough!
The typical thyroid test your doctor is running is not a good indicator of your thyroid function. Most of the time the conventional thyroid tests are only looking at TSH (A pituitary hormone) and T4 (inactive thyroid hormone). TSH, time and time again, is shown to be a poor measure of overall thyroid function.
“TSH is a poor measure for estimating the clinical and metabolic severity of primary overt thyroid failure” (1).
Nevertheless, nearly every doctor relies on this marker to treat their patients. So if your TSH comes back normal, but intuitively you know something isn’t right, what’s your next step? Your next step is to get a comprehensive thyroid assessment so you can see exactly where your imbalances are occurring. Thyroid dysfunctions occur in many different ways. The picture above shows all the different things that can affect thyroid function, all the way from the brain to the gut.
The problem with typical thyroid testing is the majority of treatment is dictated around TSH levels. Your TSH is a pituitary hormone, not a thyroid hormone. Research has shown that essentially the brain is more sensitive to thyroxine (T4) then the rest of the peripheral tissues, so it’s possible the TSH can drop to a normal level and at the same time the surrounding tissues have not received their proper fill of T4 yet.
“The serum concentration of thyroid stimulation hormone is unsatisfactory as the thyrotrophs in the anterior pituitary are more sensitive to changes in the concentration of thyroxine in the circulation than other tissues … It is clear that serum thyroid hormone and thyroid stimulating hormone concentrations cannot be used with any degree of confidence to classify patients as receiving satisfactory, insufficient, or excessive amounts of thyroxine replacement” (2).
The question begs to be asked, “Are we treating a lab test or the patient?” The more we use a series of lab tests and incorporate other subjective and objective markers into the care plan, it’s my belief the patient will start getting better faster.
Below are a series of lab tests that are a must to run to evaluate a patient’s thyroid function.
I also recommend running T4 total and free, T3 total and free, thyroglobulin, reverse T3, and T3 uptake. It’s important to assess the body’s ability to convert T4 (inactive thyroid hormone) to T3 (active thyroid hormone). Any time we see a normal level of T4 followed by a low level of T3, we know there is a conversion issue. On a conventional thyroid test, T3 would never be assessed and you would probably slip through the cracks of the medical system with an undiagnosed hypothyroid.
It is important to assess the levels of free hormones because those are the only hormones available to the receptor sites. Only 2% of hormones are free, meaning that they are not bound to a protein carrier and are therefore free to bind to a receptor site and create a metabolic response. About 98% of thyroid hormone is bound, so running both free and total thyroid hormone gives you a good perspective into the gland’s overall strength, the ability to convert T4 to T3, as well as the ability for thyroid hormone to bind to receptor sites. With this information, if a patient is having thyroid imbalances, a customized program can be used to help gently push them back into hormonal balance.
Did you know that 90% of all thyroid conditions stem from an underlying cause of autoimmunity? (3) Essentially the immune system is producing various antibodies that attack the thyroid tissue. Thyroid Peroxidase Ab (TPO), and Thyroglobulin Ab (TG) are produced in Hashimoto’s thyroiditis, which is an autoimmune condition that causes hypothyroid function over time. Thyroid Stimulating Immunoglobulin Ab (TSI) is produced in Graves’ disease, an autoimmune condition that causes hyperthyroid function.
At a minimum it’s important to at least ask your doctor to run TPO and TG antibodies to see if your thyroid condition is autoimmune in nature. Most medical doctors resist running these antibodies because it doesn’t change conventional protocol. From a functional medicine paradigm it’s important to know if you are autoimmune because it changes the overall approach to how the thyroid is treated. Any time any autoimmune condition is present, the focus needs to be more on the immune system and the gut and less on the thyroid or injured gland.
The Most Important Lab Tests
TSH: Pituitary hormone that signals the thyroid to make T4, a poor marker of thyroid status unless elevated.
Total T4: 98% of T4 thyroid hormone that is inactive and protein-bound.
Free T4: 2% of T4 thyroid hormone that is active and freely bound.
Total T3: 98% of T3 thyroid hormone that is inactive and protein-bound.
Free T3: 2% of T3 thyroid hormone that is active and freely bound.
Reverse T3: Sign of a stressed physiology and a slower metabolism.
Thyroglobulin: Increases with birth control pill and higher levels of estrogen, decreases with elevation in testosterone like in PCOS.
TPO Antibody: 70% of autoimmune patients are positive for TPO.
TBG Antibody: Less likely positive but should still be tested to rule out autoimmunity.
TSI Antibody: Autoimmune condition that causes hyperthyroidism or Graves’ disease.
There are some excellent calculated ratios that you can perform that can provide an additional data point to assess your overall thyroid function.
Most Important Calculated Ratios (4)
TT3/RT3 Ratio: 10-14
RT3/Free T3: Ratio 20-30
“The T3/rT3 ratio is the most useful marker for tissue hypothyroidism and as a marker of diminished cellular functioning.” (4)
1. British Medical Journal PMC143526.
2. British Medical Journal PMC1341585
4. The Journal of Clinical Endocrinology & Metabolism 2005; 90(12):6403–6409