Top Tests to Assess Thyroid Health
One of the most common questions I get asked by patients is whether their thyroid is off. There is a lot of confusion out there about what tests need to be run to assess the thyroid properly and, more often than not, the thyroid has been significantly under-tested and many diagnoses have been missed.
Time and time again, I’ve seen patients come in with “normal” labs from their primary care. They’ve been told that everything is “fine” and there’s no explanation for their extreme fatigue, weight gain, difficulty concentrating, abnormal periods, etc, etc.
But when we run a comprehensive lab panel, usually a very different story is told. And for the first time in years, that person is able to walk away with a treatment plan that will help them to get their old life back again.
Today, we’re going to talk about what comprehensive testing of the thyroid gland looks like so that you are empowered to advocate for yourself in the doctors office.
Thyroid 101
Meet your thyroid - master of metabolism. The thyroid is a butterfly-shaped gland at the base of your throat. While this gland is small, it is mighty.
After a signal from the brain (TSH), the thyroid produces a hormone called T4 (the 4 indicates the number of iodine molecules). T4 is released into the body and at some key sites such as the liver, it is transformed into T3. T3 is the metabolically active form of thyroid hormone - meaning it’s associated with all the heart-rate-increasing, metabolism-boosting effects that thyroid hormone is famous for. T3 is about 4x more potent than T4, so we tend to have less of it circulating in our blood.
Is TSH enough?
TSH is the signal from your brain that tells your thyroid gland what to do. The higher the TSH, the louder your brain is “yelling” at your thyroid to produce hormones.
In many conventional clinics, when you get your “thyroid tested”, your doctor will simply run a TSH and stop there.
I argue that this is not enough.
Firstly, a standard TSH lab range is roughly between 0.45 - 4.5. Notice how large that range is. Many patients have received a lab test with a TSH of 4.49 and have been told their thyroid function is normal, nevermind they’re sleeping 14 hours a day. But since there is such a large spectrum, we have to consider whether that value is optimal.
Secondly, it is possible to have thyroid dysfunction with a normal TSH. I have personally diagnosed many cases of central hypothyroidism - where TSH is normal but T3 and T4 are not - in my office. Thyroid antibodies indicating autoimmune disease like Hashimotos can also become elevated long before TSH does. Catching these early can make a huge difference in a patient’s diagnosis and disease progression.
What makes a complete thyroid panel?
So what does every new patient in my practice receive for thyroid lab testing? This list details the comprehensive lab panel I run on every new patient, what that lab tells us, and what an optimal value is.
TSH: a signal from the pituitary gland in the brain to the thyroid gland.
Range: anywhere from 0.45 - 4.5 to 0.3 to 5.6 (depending on the lab)
Optimal value: 0.5 - 2 uIU/mL
If TSH is high, it indicates a problem with thyroid gland underproduction. This is known as primary hypothyroidism. If TSH is high, it indicates thyroid overproduction and is known as primary hyperthyroidism.
Free T4 & Free T3: the “free” here refers to hormones that are unbound by binding proteins in the bloodstream. Most of our total thyroid hormone production is bound in the bloodstream, meaning that it cannot bind to our cells and give us more energy or a higher metabolism. Looking at the free thyroid hormone levels tells us what is actually available for your body to use.
Free T4 range: 9-23 pmol/nL or 0.69 - 1.79 ng/dL
Optimal value: 15 - 23 pmol/nL or 1.16 - 1.79 ng/dL
Free T3 range: 3 - 7 pmol/nL or 1.9 - 4.5 ng/mL
Optimal value: 5 - 7 pmol/nL or 3.2 - 4.5 ng/mL
If thyroid hormone levels are both low and TSH is high, this can be a confirmative sign of primary hypothyroidism.
If thyroid hormones are high and TSH is low, this is a sign of primary hyperthyroidism.
If TSH is normal but hormones are low, this tells us the brain and thyroid are not communicating and is called central hypothyroidism.
If T4 is normal but T3 is low, this is a conversion issue and may
Total T4 & T3: similar to the “free” thyroid hormone we just talked about, the “total” amount includes free hormones + those that are bound to proteins. Since the total number includes hormones that cannot bind, we always look to the free T3 and free T4 when assessing a patient’s thyroid health.
Thyroid antibodies: these are parts of the immune system that have been triggered to attack pieces of your thyroid gland. Depending on the antibody, they will either cause low (hypothyroid) function - Hashimoto’s disease - or high (hyperthyroid) function - Grave’s disease. When these antibodies are present, it means something very different than when they are not. Interestingly, most conventional offices will only run antibodies when TSH is off, however, we have seen many cases where antibodies are increased well before the TSH changes! For this reason, a complete look at thyroid antibodies is a critical piece of every thyroid screening panel.
Anti-thyroglobulin
Anti-TPO
TSI
Cortisol: cortisol changes thyroid production - if your provider has not looked at salivary cortisol, or at the very least serum cortisol, it’s time to look elsewhere! Cortisol decreases the amount of T4 that gets converted to T3 and increases the amount of T3 that gets converted to rT3.
Cholesterol: hypothyroid (low thyroid function) can cause an increase in your lipid panels - particularly total cholesterol, LDL and HDL. If you’ve had an irregular lipid panel, ask your provider to assess your thyroid to see if it might be the cause.
What else should I know before testing?
Never take your thyroid hormones morning of testing - this produces a falsely elevated reading of thyroid hormone and an a falsely low TSH
Stop taking anything containing biotin for at least 48 hours prior - biotin can also impact your thyroid labs, leading to incorrect readings. For the best results, check all your supplements for biotin (particularly anything related to growing healthy hair, skin and nails!) and stop taking it for at least 2 days prior to your blood test.
Take Control of your health journey
If you are ready to get to the root cause of your thyroid concerns, reach out to the EmpowerMed team of naturopathic doctors today. We take a collaborative approach to natural medicine, partnering with patients to help them achieve their unique health and wellness goals.
Contact us today at 760-456-7501 or use our booking link to schedule.
EmpowerMed Clinic is located just off the I-15 and Carroll Canyon within the Fitness Quest 10 Wellness Center of Scripps Ranch, San Diego County, CA. We serve the communities of North County San Diego, Poway, Rancho Bernardo, 4S Ranch, Mira Mesa, Ramona, Scripps Ranch, Santee, and more.
Written by Dr. Carleigh Golightly