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Understanding Thyroid Lab Markers

Welcome to the Gut Honest Truth blog where a Certified Functional Medicine Practitioner gives you digestible information to tackle your chronic health concerns.

That’s me, Katie Morra;

As always, working one-on-one for your specific needs is always our top recommendation, check out our appointment options to get started with one of our licensed health care professionals today.

If you want to learn more about supporting your thyroid health, I highly recommend checking out my eBook- How to Put the Fire Out on Your $?@#*!% Thyroid.

On to the post...

What is the job of the thyroid?

The thyroid is that beautiful butterfly-shaped gland positioned in the front of the neck. It is often referred to as the thermostat of the body; as it is responsible for regulating metabolism, heart rate, digestion, muscle control, brain development, mood, temperature and bone maintenance.

Over 12% of the US population will develop a thyroid condition in their lifetime and 1 in 8 women will develop a thyroid condition in their lifetime which is 5-8x more likely than men.

Common Symptoms of Hypothyroidism or Autoimmune Thyroiditis:

  • Unexplained weight gain

  • Inability to tolerate cold

  • Unexplained fatigue

  • Dry, coarse skin and hair

  • Frequent or heavy periods

  • Scalloping of the tongue

  • Brain fog

  • Hair loss

  • Brittle nails

  • Anxiety/ Depression

  • Outer eyebrow loss

  • Low sex drive

  • Infertility

  • Constipation

  • Blood sugar dysregulation

  • Muscle cramps

  • Forgetfulness

  • Acid reflux/ hoarse voice

  • Elevated cholesterol

What Are The Thyroid Markers We Recommend Testing?

Our health care system often misses the mark when it comes to optimal thyroid care. More times than not, our allopathic counterparts will order 1-2 tests called a Thyroid Stimulating Hormones (TSH) and if you are lucky a thyroxine level (T4) and call it a day. As long as these markers fall within normal range, off you go with a clean bill of thyroid health. No further lab testing is usually done, potentially allowing the hypothyroidism or autoimmune thyroiditis to go undetected.

This is like being on a boat cruising along the Atlantic Ocean and disregarding that harmless chunk of ice floating without realizing it’s just the tip of the iceberg of a much, MUCH larger hunk of ice that is going to MESS that boat up (we all know how that movie ends... Why’d you let go, Rose? Why?!?!). What I’m trying to say is there is so much more to the thyroid picture. So let's paint that picture..

  • Thyroid Stimulating Hormone aka TSH

  • Thyroxine (total and free) aka T4

  • Triiodothyronine (total and free) aka T3

  • Reverse T3

  • TPO

  • TgAB

The TSH is like the gas light on the car, it is the signal that the car needs fuel (thyroid hormone). The T4 (inactive thyroid hormone) is like the driver turning the engine of the car on. Now that the car is on, the driver has to step on the gas pedal to make it go forward (T3, the active thyroid hormone) and get from point a to point b.

Did you know that 80% of your inactive thyroid hormone needs to be converted into the active thyroid hormone in various organs like your liver, gut and kidneys ? If you are producing enough inactive hormone but it is not being converted into active hormone, you could develop signs and symptoms of hypothyroidism. But how would you know you're not converting properly if your active hormone was never checked? You wouldn't.

Often you will find the active hormone (T3) is low because the driver is slamming on the brake of the car, converting T4 into RT3 instead. Elevated RT3 can happen due to inflammation, digestive disorders, strict dieting, infections, etc.

Lastly, you have your car's emergency flashers. On the road, when you put on your emergency lights, you are usually warning fellow drivers of something. The flashers alarm you that something just isn't right. Same thing goes for your thyroid and body. When a provider sees your antibodies creeping up or actually elevated, it starts to warn us your immune system is overreacting and misfiring. In this case it shows us that the immune system is attacking your own thyroid tissue. You can have 100% completely normal thyroid values (TSH, T4, T3, and RT3) and have completely abnormal antibody values. But how would you ever know if your provider never bothered checking them? You wouldn't.

Now on the flip side some people have an overactive thyroid which can lead to problems with fatigue, irregular menstrual cycles, frequent bowel movements, weight loss, anxiety amongst many other symptoms. And as a general rule of thumb people with thyroid conditions can sway back and forth between hypo- and hyperthyroidism. People with hyperactive thyroid conditions tend to have too much fuel in the car and speeding right along.

What are the Optimal Ranges for the Markers?

You may have heard the phrasing "functional or optimal ranges" when it comes to lab work before but perhaps no one has ever truly explained the meaning. A fun fact, thyroid lab markers originated by not only considering normal thyroid function but also those patients with abnormal thyroid function within the reference ranges. Optimal aka functional ranges usually fall in a much tighter reference range, where your body is more likely to thrive, versus potentially be "high normal" or "low normal" and be a tenth of a decimal away from a "sick diagnosis". Below you can see a comparison of the ranges for each aforementioned lab marker.

How are Thyroid Hormones Created?

Without getting too far into the science and nitty gritty, below is a graphic showing us the process in which thyroid hormones are synthesized. It all starts in the brain! Our body is always monitoring how much thyroid hormone we have and need for optimal functioning and in response the pituitary gland will release (or not release) thyroid stimulating hormone aka TSH.

Thyroid stimulating hormone will communicate to the thyroid gland to release or not release more thyroid hormones (90% T4, 10% T3) based on the monitored level. Once the thyroid gland creates and releases thyroxine (T4) it must be converted to it's more metabolically active counterpart, T3, via the 5-deiodinase pathway in order for the body to reap all the metabolic activity from the thyroid.

It is also important to note that the hormones created by the thyroid are protein-bound hormones. Bound so that they can be transported throughout the body to be used in various tissue by binding to thyroid receptor sites. However, a note of equal importance, only free hormones (not bound to a protein like albumin or sex-hormone binding globulin) can actually bind to receptor sites and used. Which is why advocating for your free hormone levels to be tested, especially the more metabolically sound T3, is vital to your thyroid and health.

How Do I Find a Practitioner That Orders a Full Thyroid Panel?

If you need more support getting a proper thyroid panel done and support along your thyroid healing journey, schedule a consultation today with our Institute for Functional Medicine trained and certified health care practitioners. Alternatively, if you are in search of a prescribing physician, head to the Institute for Functional Medicine's Find a Practitioner link and search for knowledgable professionals within your area.

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