Understanding Thyroid Labs and What To Test For
Years ago I had my thyroid checked because I thought I possibly had hypothyroidism but when I met with my doctor to find out the results she told me everything was normal and sent me on my way. This is unfortunately a very common story for those with hypothyroidism and if I knew what I’m about to share with you here I could have addressed sub-clinical hypothyroidism before it disrupted my health.
I later found out that it often takes 10 years of slowly developing thyroid issues before conventional medicine recognizes there is an issue.
And about 60% of hypothyroidism patients go undiagnosed their entire life. Many woman have been turned away by doctors, told that their issues are in their head, or that their weight problems have nothing to do with their thyroid and everything to do with their fork. Meanwhile they continue to feel all the uncomfortable symptoms of hypothyroidism.
The following information is to help you advocate for yourself so that healing can begin.
Topics:
Why hypothyroidism is commonly misdiagnoses
What tests to have done
What are optimal lab ranges
What your lab results might mean
If you haven’t seen my post Hypothyroidism 101, you may want to take a read before diving into lab testing. The article goes into what the thyroid is, it’s function, symptoms and causes of hypothyroidism, as well as ways to support thyroid health.
Why is hypothyroidism so commonly misdiagnosed?
There are three main reasons: Incomplete lab testing, inadequate lab ranges, and undiagnosed Hashimoto’s thyroiditis.
1. Incomplete Lab Testing
Conventional medicine traditionally only tests for something called thyroid stimulating hormone (TSH) to diagnose a thyroid condition. This can be problematic because TSH is only the hormone that requests thyroid hormones to be produced. TSH does not measure whether or not the actual thyroid hormones were produced, let alone if they made it to our cells to be used.
Testing only TSH is like determining that a job you want done is complete based on sending out an email requesting someone to do the job. But what if the person didn’t listen? Was unable to do the job? Or didn’t do it right?
This is what can happen with thyroid hormones. TSH requests (signals) the production of thyroid hormones, primarily thyroxine (T4), and a tinny bit of triioodothyronine (T3). Once that happens, T4 has to be converted into T3, which is the useable form of the thyroid hormone. Sometimes there’s an issue with this conversion though.
This means TSH and T4 can look great while T3, the hormone we actually care about, is low. So as conventional medicine usually doesn’t test for T3, many people are told their thyroid is fine when they actually have hypothyroidism. Imagine how frustrating. We know our bodies best, and to know you feel really off and be told it’s in your head… ugh, makes my cheeks flush just thinking about it.
But that’s not the only issue that can happen with thyroid hormones. Sometimes T4 is converted into something called reverse T3 (RT3) instead of T3, which is not useable yet still binds to the receptor sites on our cells, blocking any useful T3 that was produced from being utilized. It’s like when you put a key in a lock upside down - it goes it, but doesn’t work. And you also can’t put the key in that works when the locks already full!
2. Inadequate Lab Ranges
Normal lab ranges are based on the “average population” not the “healthy population,” and include those with hypothyroidism, making it an incredibly poor reference range. This means your TSH thyroid levels have to be really off for it to gain any attention as far as conventional testing goes and this can take up to 10 years of thyroid issues brewing. Leaving people with fatigue, weight issues, brain fog, poor digestion and more, unnecessarily.
With any lab testing, optimal ranges should always be referenced because what is normal is not what we want. It’s normal to be unwell. We want optimal.
3. Hashimotos Disease
Hashimoto’s thyroiditis is an autoimmune disease where the body’s immune system attacks the thyroid gland. The damage this does to the thyroid gland leads to an underproduction of thyroid hormone or hypothyroidism, but diagnoses can be complicated because lab results for Hashimoto’s patients vary from week to week. They can present as hyperthyroid, hypothyroid or “normal”, and they also have a range of symptoms that may not be clearly hypothyroidism at first glance.
This is why it’s important to test for Hashimoto’s whenever a thyroid issue is suspected. A great way to check for Hashimoto’s is by testing antibodies including Thyroid Peroxidase Antibodies and Thyroglobulin Antibodies (TPO Antibodies/TG Antibodies). These tests can help catch Hashimoto’s early, and will often show on a lab test years or decades before TSH rises.
What tests should I speak to my doctor about?
The good news is that hypothyroidism can be easily diagnosed with proper testing and the use of optimal lab ranges.
Proper testing includes:
• Thyroid Stimulating Hormone (TSH)
• Free T4 (FT4)
• Free T3 (FT3)
• Reverse T3 (RT3)
• Thyroiglobulin antibodies (TgAB)
• Thyroid peroxidase antibodies (TPO)
Free T4 and Free T3 are different than the lab tests for Total T4 and Total T4. Free means it is the unbound form and this is what you want to test for. When thyroid hormone is bound to a protein, it can interfere with its ability to reach certain tissues.
Other useful tests to assess associated problems or conditions include celiac disease or gluten intolerance, microbiome health, food sensitivity, immune health, heavy-metals, sex hormones, yeast, mold, nutritional evaluation, and stress evaluation.
What are optimal lab ranges for thyroid hormones?
These ranges reflect numbers where patients typically report feeling their best. These are based on the findings of thyroid experts Amy Meyers and Dr. Will Cole, as well as my personal experience.
TSH: 1-2 mIU/L.
Free T4: 1.0-1.5 ng/DL
Free T3: 3.0-4.0 pg/mL
Reverse T3: less than a 10:1 ratio RT3:FT3
Thyroid Peroxidase (TPO) Ab: 0-15 IU/mL
Thyroglobulin Ab: 0-0.9 IU/mL
What if my labs are “Perfect” but I still have Hypothyroid symptoms?
If your labs are within optimal range but you still feel hypothyroid symptoms you may have cellular hypothyroidism. This is when the cells don’t receive the thyroid hormones, even if you have optimal levels. One of the causes of this is inflammation, which can block the cell receptors for thyroid hormones (this also happens with other hormones like progesterone).
What Now?
If you know you have hypothyroidism, the next step is to support the thyroid and find a practitioner like myself to support you. Like any imbalance in the body, it’s essential to determine and address the root cause. While thyroid medication can help you feel like yourself again, it doesn’t address WHY there is an issue and really acts more like a band-aid. Many people also often find they don’t feel well even when they’re taking a thyroid medication, either because they are on the wrong medication or dose, or because their lifestyle and eating habits haven’t been adjusted to optimize thyroid function.
Everyone has a unique story, but my personal experience with hypothyroidism was that I was able to reverse it with lifestyle and diet alone, and never went on a thyroid medication. I am completely back to feeling like myself, full of energy, mental clarity, and am truly happier than I have felt in years. This is not going to be everyones experience, sometimes you just need a little bit of supplemental thyroid hormone to help you out, but it does go to show how powerful lifestyle and diet are.
As always, this article is for informational purposes only and is not personal medical advice. This article is not meant to treat or diagnose any condition. Please read full disclaimer here.