All About Thyroid Testing
By Dr. Emily Wiggins
We often have patients and clients coming to the clinic having been told by their provider that their thyroid is normal and doesn’t have anything to do with how they are feeling.
Once we review their most recent thyroid test results, we see that their provider either ran only one or two markers in testing their thyroid, they ordered the wrong tests to assess thyroid health and/or their provider was using a “normal range” that doesn’t necessarily mean their thyroid is functionally normally or optimally. It’s getting better slowly but unfortunately, thyroid imbalances are often underdiagnosed and that leaves a lot of people feeling discouraged and dismissed by their providers.
In this article, we’ll cover common symptoms of thyroid imbalance and our recommended tests as well as the optimal ranges we like to see in assessing thyroid function.
Spoiler alert: there is also an additional assessment we like to use to compliment blood testing that gives us even more information about thyroid and metabolic function.
Symptoms of Hypothyroidism
Menstrual irregularities
Infertility
Constipation
Acne
High cholesterol
Blood sugar imbalance and diabetes
Muscle loss
Weight gain
Fatigue
Dry skin
Hair loss
Thinning eyebrows
Depression
Feeling cold
Low immunity
What does a full thyroid panel include?
TSH
Free T4
Free T3
Reverse T3
What does it mean to have normal thyroid labs?
Reference ranges provided by a lab are determined by a percentage of the population that particular lab sees. That means a lab takes all the TSH results for all the patients they have tested and determines their normal range so that a certain number of their patient population falls within the range.
It is not a reflection of an optimally functioning thyroid. This is why different labs have different reference ranges and they can change from time to time. It is much better practice to use optimal ranges when assessing thyroid function.
Normal Functional Ranges for Thyroid Tests
TSH
TSH testing is measuring how your brain is communicating to your thyroid. As the number increases, it’s a reflection that the brain is asking the thyroid to make more thyroid hormone. Thyroid medication can interfere with the feedback loop in the body regarding thyroid hormone so that must be taken into account when assessing TSH levels. TSH should be close to 1 mIU/L and less than 2 mIU/L.
Free T4
The thyroid releases a vast majority of its thyroid hormone in the form of T4. This is the inactive form of thyroid hormone. T4 levels should be between 1.20-1.66 ng/dL
Free T3
When the body needs thyroid hormone T4 is converted to T3 wherever it is needed in the body. T3 is the active form of thyroid hormone and is needed all over the body, which is why low thyroid symptoms can be seen in so many systems. Free T3 levels should fall between 3.16 - 4.28 ng/dL.
Reverse T3
T3 can be converted into reverse T3 due to stress, chronic illness, low mineral status or other hormone imbalances. This is also a good marker to gauge response to desiccated thyroid therapies when a person has Hashimoto’s Thyroiditis. Reverse T3 should be between 8-12 ng/dL.
Thyroid Medications & Testing
If you are taking thyroid medications, testing should be done at different times based on the medication you are taking.
If you are taking levothyroxine, it doesn’t matter when you have your blood drawn relative to your thyroid medication.
If you are taking dessicated thyroid, labs should be drawn 3-4 hours after taking your medication
If you are taking liothyronine, you should have your labs drawn 2-3 hours after taking your medication.
A Simple Way to Get More Information about Your Thyroid
The simplest way to get more information about your thyroid is to start taking your basal body temperature and pulse each morning. A properly functioning or supported thyroid will result in body temperature consistently over 97.7 degrees fahrenheit. Pulse will ideally be around 70 beats per minute. You can get even more information if you repeat the temperature and pulse about 20 minutes after breakfast. This helps differentiate if your basal body temperature upon waking is falsely high due to elevated cortisol levels that would theoretically decrease following breakfast. Basal body temperature is a good reflection of metabolic function and can also be helpful in determining adequate thyroid hormone therapy.
If your provider isn’t running a full thyroid panel when assessing your thyroid, it is time to find a provider that will. This is particularly important if you are identifying symptoms of thyroid imbalance in yourself.
Get Support from our Naturopathic Doctors
If you’re interested in further support and want to chat with one of our doctors, book a discovery call to discuss some of the specifics of what you’re dealing with and see if we’re a good fit.
