Thyroid testing: what it can reveal about your thyroid and health
Table of contents
- Thyroid hormones: free T3 and T4
- TSH: thyroid-stimulating hormone
- TPO antibodies (TPOab)
- Why take a thyroid test?
- Related content
Excessive fatigue. Depression. Anxiety. Difficulty sleeping. These are a few of the telltale signs of a poorly-functioning thyroid gland. And these aren’t all the potential symptoms of a malfunctioning thyroid gland, either. In fact, many possible symptoms can occur when something’s wrong with your thyroid because of the pivotal role it plays in your body.
So how can you check up on the health of your thyroid?
The answer: with our at-home thyroid blood test. This test is not only super convenient (it’s sent straight to your doorstep, so you can take it at home), but it also measures 4 key markers associated with thyroid function – instead of just one (as some thyroid tests do). Of course, that begs the question, “What markers does the Everlywell Thyroid Test measure?”
This thyroid test is designed to measure the following four markers found in your blood: free T3, free T4, TSH, and TPOab. If that string of acronyms plopped a giant question mark in your mind, then don’t worry – here, we’ll break down exactly what these different markers are (and why it’s a good idea to monitor them).
We’ll begin with free T3 and free T4.
Thyroid hormones: free T3 and T4
Place a couple of fingers on the front of your neck. That’s (approximately) where your thyroid gland is located, hugging your windpipe. However, most people aren’t able to feel their thyroid gland because of its small size.
You absolutely need this little gland, though, because it produces two very important hormones (chemical messengers sent throughout the body): T3 and T4.
When the thyroid pumps these hormones into your bloodstream, many of them are bound to proteins – and are thus inactive. Some T3 and T4 hormones, however, freely circulate in your blood – which is why they’re known as “free T3” and “free T4.”
These free thyroid hormones are instrumental in regulating your metabolism. For example, they act as signals that let your body know when to burn fat – giving you energy to power through the day.
But, precisely because they are chemical signals, T3 and T4 hormones must exist in your blood at very specific levels. Too much of these hormones, and your metabolism will slip out of balance; too little, and your metabolism will (you guessed it) also go out of order. (Problems with your thyroid and other glands, as well as various dietary supplements, can all lead to unhealthy levels of T3 and T4.)
Simply put, then, if your T3 and T4 levels aren’t within a normal range, your thyroid could be in trouble! So your thyroid hormone levels can be useful indicators of how well your thyroid – and overall metabolism – is performing. And that’s why free T3 and free T4 are among the markers assessed by the Everlywell Thyroid Test.
TSH: thyroid-stimulating hormone
TSH stands for “thyroid-stimulating hormone.” TSH is produced in the pituitary gland, a pea-sized gland found in your brain. When your thyroid hormone levels are low, the pituitary gland sends TSH molecules over to the thyroid gland – telling the thyroid to make more hormones and release them throughout your body.
Thus, you have higher levels of TSH when you’re low on thyroid hormones. On the flip side, when your thyroid hormone levels are optimal or elevated, your pituitary gland doesn’t need to release very much TSH – so you’ll have lower TSH levels in your blood.
Because of this relation between TSH and thyroid hormones, EverlyWell’s Thyroid Test – which measures your TSH levels, as well as your thyroid hormone levels – can provide you with a more complete picture of your thyroid health.
By the way, if a thyroid test reveals that your TSH levels are quite low, then this indicates that your thyroid gland might be on overdrive and spewing out too many thyroid hormones. Hence, a very low TSH reading alerts you to the very real possibility that you have an overactive thyroid (a condition known as hyperthyroidism).
(Another possibility? You’re taking far too much thyroid hormone medication or supplements.)
Now, consider the opposite situation: what if you have very high levels of TSH? In that case, your thyroid may be barely working – and failing to supply your body with enough thyroid hormones. As for why your thyroid would be underperforming? There are many potential reasons, so it’s best to consult with your healthcare provider if your TSH levels are low.
TPO antibodies (TPOab)
Bustling within the thyroid gland are tiny molecular devices bearing the name “thyroid peroxidase.” Thyroid peroxidase – or TPO for short – helps manufacture thyroid hormones (T3 and T4, which we introduced you to earlier). If that sounds like a good thing to you, you aren’t wrong! The thyroid gland needs the hormone-making power of TPO to provide your body with a steady supply of thyroid hormones.
In some people, though, certain immune molecules – termed TPO antibodies, or TPOab – prevent TPO from carrying out its function. These molecules stick to TPO – the molecular equivalent of gumming up the works. TPO then grinds to a halt, which ceases production of thyroid hormones.
Your TPOab levels – which the Everlywell at-home Thyroid Test measures – can help pinpoint the cause of low thyroid hormone levels. If you have too much TPOab – and your thyroid hormone levels are much too low – then your thyroid gland probably isn’t able to produce enough of its hormones. The most likely culprit behind this situation is an autoimmune disorder of some kind. Antibodies are part of your immune system (and remember that TPOab is an antibody). But when the immune system malfunctions, antibodies can attack healthy glands (like the thyroid) and disrupt their function.
Why take a thyroid test?
When something goes wrong with your thyroid gland, your whole body – and health – can pay a steep price. And thyroid diseases aren’t all that rare: around 20 million Americans have a thyroid disease, and over 12% of people in the United States will have some kind of thyroid malfunction at some point in their lives. Because of these statistics – and because the thyroid gland needs to work properly for optimal health – you may want to take a thyroid test (especially consider a thyroid test if you have symptoms of thyroid disease).
Related content
How to test for hypothyroidism