Review: WellnessFX Advanced Thyroid Blood Test

I found WellnessFX a few years ago when I was looking into websites to store all my blood tests and order new ones if needed. I've found this site to be a nice platform to keep all my lab results in one place and visualize trends over time.

Recently I decided to order their Advanced Thyroid blood test, a comprehensive set of eight measures of thyroid function.

Why test your thyroid?

More than 12 percent of the US population will develop a thyroid condition during their lifetime.[1]

This butterfly-shaped gland in your neck is part of your endocrine system and responsible for the release of two hormones: triiodothyronine (T3) and thyroxine (T4).[2]

Thyroid hormones play a critical role in the body by helping the body regulate metabolism, stay warm, and keep the brain, heart, and other organs working properly.[2][3]

An underactive thyroid can result in low energy, weight gain, and cold intolerance, while an overactive one can cause hyperactivity, undesired weight loss, and heat intolerance.

The most common cause of thyroid overactivity (hyperthyroidism) in the US is Graves' Disease, which affects one in 200 people, and is 7-8 times more common in women than men. An underactive thyroid (hypothyroidism), is most commonly caused by Hashimoto's Disease which results when your body attacks your thyroid.[4]

What's included in the test

A common test is to measure your thyroid-stimulating hormone (TSH), but this can't always pick up when a person's thyroid is malfunctioning.

The WellnessFX package includes several additional biomarkers and is similar to a "full" thyroid panel that might be ordered at a doctor's office.

  • Thyroid-stimulating hormone (TSH) – TSH is produced by the pituitary gland in your brain and triggers the thyroid to produce hormones. The number of hormones in your bloodstream then give the pituitary gland feedback as to how much TSH to release so the brain will release more or less as needed. TSH is therefore used as the primary screening test for thyroid disease, where too much TSH indicates that enough hormones aren't being released, evidence of an underactive thyroid, while too little TSH indicates the opposite, an overactive thyroid.[5]
  • Total thyroxine (total T4) – T4 is the main hormone produced by the thyroid and is inactive until converted into T3 which occurs mainly in the liver. Thyroid hormones circulate in the bloodstream bound to transport proteins which cannot enter tissues to exert their effects unless "free" or unbound to a protein. The free and bound T4 together is the total T4.[6][7]
  • Free thyroxine (free T4) – The measure of T4 not bound to protein is called free T4 and is the most important test to determine how the thyroid is functioning. Individuals who have overactive thyroids will have elevated levels of free T4, while those who are underactive will have low levels.[6][7]
  • Total triiodothyronine (total T3) – T3 is the active form of the hormone T4 and is mostly converted in the liver. Thyroid hormones circulate in the bloodstream bound to transport proteins which cannot enter tissues to exert their effects unless "free" or unbound to a protein. The free and bound T3 together is the total T3.[8][9]
  • Free triiodothyronine (free T3) – The measure of T3 not bound to protein, and therefore available for the body, is called free T3. A test of T3 is often useful to diagnosis overactive thyroids or to determine the severity of the condition, where an elevated T3 level is usually seen. It's not usually helpful for people with underactive thyroids since it is the last test to become abnormal.[8][9]
  • T3 resin uptake (T3RU or T3 uptake) – Most thyroid hormone is inactive and bound to a protein called thyroxine-binding globulin (TBG). The T3 uptake test helps to estimate the amount of TBG protein available for binding to the hormones, as too much or too little can throw off the other measurements of T3 and T4. Therefore, the test is used to correct for certain medications that affect TBG levels such as birth control pills, cardiac drugs, or even aspirin. In general, the less thyroid binding proteins the more your T3 uptake is elevated, because a higher percentage of those binding proteins need to be used.
  • Free thyroxine index (FTI or T7) – FTI estimates how much free, active T4 you have available after correcting for medications or other abnormalities that may affect protein binding. It's obtained by multiplying total T4 by the percent of T3 uptake, but has been largely replaced now that reliable tests for free T3 and free T4 are available.[10]
  • Reverse T3 (RT3) – RT3 is a byproduct of thyroid hormone metabolism and is elevated during sickness. Your body converts T4 to RT3 as a way to get rid of any unneeded T4, and when your body needs to conserve energy for other purposes such as illness or physical stress, it will decrease the production of T3 and increase the conversion to RT3. Excess RT3 can be a sign of stress decreasing your active thyroid production.[10]

The testing process

After you purchase a blood test through WellnessFX you will be directed to make an appointment with Quest Diagnostics, a medical laboratory with locations across the US.

On the day of the appointment, I drove over to the hospital (where this Quest lab was located), parked, went in and had three vials of blood drawn. It couldn't have taken more than 15 minutes.

Four days later I had a notification in my email inbox telling me the lab results were ready. On their website, I could easily compare my results against the reference values and order a consultation with an expert if necessary. They have a convenient iPhone app too.

Final thoughts

If you want to go beyond the standard TSH test or have concerns about your thyroid function and metabolism, the comprehensive testing offered by WellnessFX is a great option. It's on par with what might be ordered at a doctor's office and their platform makes it easy to compare trends over time.

Read more about the details of their thyroid test.