The Best At-Home Thyroid Test

Problems with thyroid health may be more common than you expect. Up to 60% of the 20 million Americans estimated to have thyroid disease are unaware they have the condition.1 Thyroid conditions are particularly prevalent among women — they’re 5-8 times more likely to develop issues compared to men.9 With such a high percentage of people being unaware of potential thyroid concerns, it’s essential to learn if your thyroid is functioning correctly as soon as possible and to re-check routinely.

With the growing popularity of at-home testing, several companies offer a variety of thyroid tests you can take at home with accurate, easy-to-understand results. We’ve tested these companies and their products to help you determine which at-home thyroid test may be best for you.

Read on for all the details, but for those in a hurry, here is a summary of our main findings:

Over the past two decades, Innerbody Research has helped tens of millions of readers make more informed decisions to live healthier lifestyles through research-backed evaluations of products and services.

We extensively test each product and service we review, including the thyroid testing services in this guide. All told, our team has spent over 125 hours gaining hands-on testing experience and conducting research on the thyroid, at-home thyroid test kits, and the companies behind the kits. When evaluating products and services, we base our judgment on each company’s adherence to health and quality standards, along with the latest medical research.

Additionally, like all health-related content on this website, this review was thoroughly vetted by one or more members of our Medical Review Board for accuracy.

When we evaluate products or services, we examine them based on a set of criteria. In the case of at-home thyroid tests, we graded them according to cost, speed, ease of use, and customer care. When it comes to accuracy, both of the at-home testing methods used by our top picks (wet and dry blood samples) appear to be pretty much equal in terms of maintaining the stability of the proteins in blood. However, drying a sample “slightly but consistently” influences detectability when stored for extended periods of time (30 years).31 This shouldn’t be a concern when it comes to these at-home tests, though.

Cost

Winner: LetsGetChecked Thyroid Antibody Test

Our evaluation of cost had a lot more to do with what you get for your money than who had the lowest price. Technically, the least expensive thyroid test comes from Healthlabs, but it pales compared to its competitors in terms of overall convenience. And while the LetsGetChecked Thyroid Antibody test is about $20 more than Paloma Health’s, its additional measurement of thyroglobulin antibodies (instead of just thyroid peroxidase antibodies) makes it more worthwhile in our book.

Here’s a quick breakdown of basic costs:

While Paloma Health can check up to six biomarkers, the default test checks four, and the additional two are add-ons that each cost a fee: reverse T3 ($64) and vitamin D ($53).

Additionally, we were disappointed to see how much the cost of Everlywell’s thyroid test increased since we last evaluated it — roughly $50 more, with nothing new added on to justify the price increase. Even with a subscription, it’s still almost $30 more than it was before.

Speed

Winner: LetsGetChecked

Our speed rating included everything from shipping and test turnaround time to the time it takes to navigate a website for purchases and find answers to common questions. At every turn, LetsGetChecked excels, with an intuitively laid out website and a turnaround that, for our testers, took just eight days from the day we placed the order to the day we had results.

Our testers were impressed with how their samples arrived at the LetsGetChecked lab the day after they were sent via UPS. And only two days after that, they received an email with their results.

In comparison, Paloma took the longest time for testers to receive their results — 16 days after sending the sample in the mail. And myLAB Box’s turnaround time after mailing falls in between LetsGetChecked and Paloma at 12 days.

Ease of use

Winner: Paloma Health

While Paloma wins for overall ease of use due to its particularly user-friendly and easy-to-understand results interface, it’s actually tied with nearly all the other at-home tests mentioned when it comes to taking the test itself. Paloma, myLAB Box, and Everlywell all use dried blood spot (DBS) testing, where you poke your finger and let the blood drip onto a handful of designated spots labeled on a card.

LetsGetChecked used to use this same method but swapped to using a vial (capillary blood collection). The company doesn’t include any sort of funnel or way to ensure blood easily flows into the vial, making sample collection a chore compared to competitors. We hope LetsGetChecked will reevaluate its collection methods in the future to better align with the convenience of its competition.

Customer care

Winner: Paloma Health

For this category, it was a close call between Paloma Health and LetsGetChecked. However, the former won due to a few additional steps taken by the company. When your Paloma results are ready, you’ll receive both an email and a text letting you know they’re ready for you to review. Paloma also offers a wealth of resources dedicated to helping you learn more about thyroid health, including guides, articles, recipes, videos, and telehealth visits with doctors who specialize in thyroid care. (LetsGetChecked also offers consultations with medical professionals but with nurses instead of doctors.)

And, if your results come back as non-hypothyroid, Paloma offers you a 30% off coupon for additional tests from LetsGetChecked. (Paloma seems to have recently partnered with the company, based on emails received by our testers.)

LetsGetChecked also excels in customer care. The company’s customer service email responses are quick and thorough, and the representatives on the customer service phone lines have enough information about tests and processes that they rarely need to run questions up the chain to get you an answer. Additionally, on the STD side, the company even offers free delivery of medications after specific positive test results.

To understand how blood tests help identify thyroid disorders, it’s important to know a bit about the thyroid and the specific substances these thyroid tests measure.

Located below the larynx at the front of the neck, the thyroid is a small gland with two lobes connected by a bridge of tissue. Although not very large, the butterfly-shaped thyroid gland plays a significant role in ensuring the proper function of the brain, heart, kidneys, liver, metabolism, and skin. The thyroid accomplishes this system regulation by secreting hormones into your bloodstream.2

When ordering a thyroid test, you’ll likely come across a lot of terminology about these various hormones (and other components) that can be confusing at times. The chart below offers a breakdown of the typical cast of characters in these tests, along with some explanation.

Knowing the nature of these different substances reveals why thyroid blood tests are a powerful tool in identifying disorders. You could think of the hormonal regulation of a healthy thyroid as being a little like a thermostat. When a room gets too hot or cold, the thermostat signals to the radiator to produce more or less heat. This constant signal and response keeps the room at a stable temperature.

Similarly, based on how much T4 is already present in the bloodstream, hormones from the hypothalamus and pituitary gland signal to the thyroid that it needs to produce more or less T4 to keep the organs and systems of our body stable. But what happens when the thermostat or radiator doesn’t function properly? Abnormal levels of TSH, T3, or T4 can indicate that the finely tuned system is out of balance.

Thyroid conditions arise when the gland is either overactive in its hormone production or underactive and produces too little. Overactive thyroid glands create a condition called hyperthyroidism, while an underactive thyroid gland results in hypothyroidism. Problems with the thyroid usually result in the overproduction or underproduction of certain thyroid hormones.9

The overproduction of thyroid hormones, known as hyperthyroidism, can be caused by conditions such as:10

• Graves’ disease: an autoimmune disease and the most common cause of hyperthyroidism)
• Toxic adenomas: nodules developing in the gland that secrete extra thyroid hormones)
• Subacute thyroiditis: inflammation of the thyroid that results in the leaking of extra hormones)

Hypothyroidism is the underproduction of thyroid hormones. This can be caused by:11

• Hashimoto’s thyroiditis (an autoimmune disorder)
• Exposure to toxic levels of iodine
• Not enough iodine
• Pregnancy
• Pituitary gland issues
• Certain medications
• Thyroiditis (thyroid inflammation)
• Radiation therapy for cancer treatment

The chart below breaks down some of the common symptoms found in hypothyroidism and hyperthyroidism.10 11

Getting your thyroid function tested can be a good idea no matter who you are (even just to find your baseline), but some populations are statistically at higher risk of developing thyroid conditions:9

• Women or people assigned female at birth (AFAB)
• People with Type 1 diabetes or other autoimmune disorders
• New mothers
• People who smoke12
• Those with a family history of thyroid disorders
• People who have symptoms of hypothyroidism or hyperthyroidism

Women and AFAB individuals are around 5-8 times more likely to have thyroid problems, with one in eight developing thyroid disease during their lifetime. However, men can also develop thyroid disease, and symptoms present the same in both sexes.9

Since thyroid issues are common (and often go undetected), periodic testing can be beneficial regardless of your sex and whether or not you’re experiencing any symptoms of thyroid dysfunction.

Should you test at home or in person?

Whether you test at home or in person at a lab depends mainly on your personal preferences, but if you’re not sure which method would work best for you, we’ve put together a little chart to help you decide.

Of course, there are other reasons someone might want to test at home or in person (such as privacy concerns, insurance limitations, or the availability of all-in-one services like Paloma Health), but we think the convenience of the at-home testing experience is one of the biggest perks of utilizing these kits.

Below, we’ve put together a handy chart comparing each company’s most comprehensive test choices based on price and what the tests measure.

Paloma Health also offers two additional add-on biomarkers for reverse T3 ($64) and vitamin D ($53). Reverse T3 is “generally not recommended” when conducting a routine evaluation of thyroid disorders,13 as it has no clinical value except in diagnosing euthyroid sick syndrome (nonthyroidal illness syndrome).14 And, while some research shows that vitamin D appears to be lower in hypothyroid patients versus controls,15 vitamin D deficiency is also a common issue worldwide — nearly one billion people around the world are deficient.16 So, while getting your vitamin D checked may be useful, we don’t see much of a reason to opt for the reverse T3 add-on at this time.

For almost $100 less than the cost of a Paloma test with both additions ($216), you could get the LetsGetChecked Thyroid Antibody Test which includes the same biomarkers as the basic Paloma test with the addition of thyroglobulin antibodies (another test, along with TPO/TPEX, that can help diagnose autoimmune thyroid disease).7

Most comprehensive test, best for most people, fastest turnaround

LetsGetChecked is currently our top recommendation for an at-home thyroid test. The company currently offers two testing levels, the most comprehensive of which is the only test in this review to look for thyroglobulin antibodies (TgAb). LetsGetChecked also boasts exceptional speed in both shipping and lab work, and its customer service staff is friendly and knowledgeable. The main drawback of these tests is their difficult sample collection, which may be a deterrent for some people from an otherwise excellent service.

LetsGetChecked previously used dried blood spot (DBS) testing, like all of the other at-home competitors mentioned (Paloma, Everlywell, and myLAB Box), but swapped to using a vial for sample collection. If you clot easily, then this is probably not the test for you, as you’ll need to be able to bleed consistently to be able to fill up the vial to the necessary line. The company states in the instructions that failure to reach the line will render the test “incompletable.” This feels a little far-fetched to us, especially considering that all of the other at-home tests using DBS testing are just as accurate and require far less blood.

One tester had to use lancets left over from the DBS-based test kits in order to poke their fingers more and get enough blood. And the lack of a funnel or other instrument to make sure the blood actually gets into the vial just makes it even more frustrating (the little lip on the edge doesn’t help much). However, once you do manage to get your blood into the vial, a slippery coating on the internal side of the plastic ensures the sample flows to the bottom instead of clinging to the rim.

It’s also important to note that LetsGetChecked’s thyroid tests require you to collect your sample in the morning on a weekday (Monday through Friday) and send the sample off the same day. These instructions are much more rigid compared to the other at-home competitors, which don’t require a specific time or day for sample collection.

Overall, though, the unique speed and thoroughness of LetsGetChecked’s at-home thyroid tests still make it our top choice despite the frustrations our testers endured. And the company’s clear-cut results are a very close runner-up in user-friendliness behind Paloma. Additionally, being able to chart the changes in your biomarkers over time is a nice feature we really appreciated seeing LetsGetChecked, Paloma, and Everlywell offer.

Thyroid Test

The LetsGetChecked Thyroid Test ($99) evaluates thyroid function via analysis of three biomarkers:

• Thyroid-stimulating hormone (TSH)
• Free triiodothyronine (FT3)
• Free thyroxine (FT4)

This test is ideal for most people because it can effectively indicate whether you have an underlying thyroid disorder. Unless you are symptomatic or have other reasons to suspect that you have a particular thyroid disorder (due to family history, radiation exposure, etc.), we recommend this test as the first step in checking your thyroid health. It tests the three primary values related to thyroid function; these serve as the solid starting point to identify whether or not a thyroid problem is likely.

As a potential alternative, Paloma’s thyroid test costs the same ($99) and also checks for Thyroid Peroxidase Antibodies. This could be a good option (albeit with a much slower turnaround time) if sample collection sounds too difficult through LetsGetChecked.

Thyroid Antibody Test

The more comprehensive Thyroid Antibody Test ($119) includes analysis of the same three biomarkers as the smaller Thyroid Test, in addition to two more:

• Thyroglobulin antibodies (TgAb)
• Thyroid peroxidase antibodies (TPO/TPEX)

The main difference between the two kits is that the TgAb and TPEX values included in the Thyroid Antibody Test can indicate whether thyroid dysfunction is related to an autoimmune disorder. Everlywell, myLAB Box, and Paloma also test for thyroid peroxidase antibodies, but LetsGetChecked’s Antibody Test is the only one to offer testing for thyroglobulin antibodies.

The basic Thyroid Test kit can indicate if there may be an issue with your thyroid, but the more comprehensive test may provide you with insights into the underlying cause.

Subscription plans

Both LetsGetChecked thyroid tests are also available on a subscription basis (similar to Everlywell and myLAB Box) if you’re interested in re-testing occasionally over time. The chart below details the costs of one-time purchases and the various subscription intervals.

Most user-friendly results

Paloma Health is a telemedicine company with a focus on thyroid health. In some ways, that specialty purpose gives the company an edge when it comes to thyroid matters. Unfortunately, it’s not quite enough for us to recommend the service over competitors like LetsGetChecked.

One issue is that Paloma’s services are not as widely available. Specifically, it can provide test kits to every state in the U.S. except for:

• New York
• New Jersey
• Rhode Island
• Maryland

The company says that these restrictions are temporary, but there isn’t more information available about when these restrictions may be lifted. By comparison, LetsGetChecked tests are currently available in all 50 U.S. states, and myLAB Box and Everlywell are available in 49 (with the exception of New York).

When it comes to doctor consultations, Paloma has greatly increased the number of states in which this service is available. The last time we examined Paloma, these consultations were only accessible in 15 states. This has expanded to 37. The remaining 13 states where consultations are currently unavailable include:

Similarly, LetsGetChecked is also currently unable to offer consultation services in several states, many of which are also on the list above. The main reason we specifically called this out as an issue for Paloma Health is due to the fact that it's billed as a one-stop shop of sorts for thyroid health.

In terms of taking the actual Paloma thyroid test, the collection process is fairly straightforward (as was the case in all of our other dried blood spot test options). After pricking your finger with one of the included lancets and collecting your blood sample in the designated circles on the collection card, you just need to let it dry for about an hour.

After your sample has been collected and left to dry, it can be shipped off back to the lab. None of our testers reported any issues, concerns, or confusion with this process. And that ease of use also translates into Paloma’s presentation of your (long-awaited) results.

Paloma’s results layout is pretty similar to that of LetsGetChecked. However, we appreciate all of Paloma’s information (including test and result explanations) being on one easy-to-navigate page. When reading through results from LetsGetChecked, you will need to go to the individual page of each result to read more about it, which isn’t horribly inconvenient, but it can make the user interface feel a bit more complicated. Both services allow you to chart your results and biomarker trends if you continue to purchase additional test kits, but Paloma also lets you include bloodwork results from outside sources.

Paloma’s thyroid test is $99 and checks your:

• Free Triiodothyronine (fT3)
• Free Thyroxine (fT4)
• Thyroid Peroxidase (TPO/TPEX)
• Thyroid-stimulating hormone (TSH)

As we’ve covered earlier, you also can add on tests for vitamin D ($53) and reverse T3 ($64) levels, though reverse T3 isn’t generally recommended when diagnosing most thyroid conditions.13 Vitamin D, however, is something a large number of people worldwide are deficient in, including those with thyroid concerns, making this a potentially beneficial add-on.15 16 The additional $53 for checking vitamin D with Paloma is less than you’d spend on a vitamin D test kit from LetsGetChecked ($89) or myLAB Box (also $89). Everlywell’s vitamin D test, on the other hand, only costs $49. This might not be a large enough savings for you to consider purchasing kits from two separate providers, but it is an alternative.

Based on our comprehensive evaluation of major testing companies across the market, we consider Everlywell to be a great telehealth brand and often recommend it over other companies for several at-home tests. But, in the case of at-home thyroid testing, LetsGetChecked is still superior — especially when you take into account Everlywell’s discontinuation of its cost-saving “Control” membership program and the hefty price increase of its thyroid test (with no discernable upgrades from how the test was before).

Everlywell’s Thyroid Test ($149) evaluates thyroid function by analyzing four biomarkers:

• Thyroid-stimulating Hormone (TSH)
• Thyroid Peroxidase Antibodies (TPO/TPEX)
• Free T3 (fT3)
• Free T4 (fT4)

As with Paloma and myLAB Box, Everlywell’s Thyroid Test utilizes dried blood spot testing. Your results should be available within five business days after the company receives your sample. This is a day or two longer of a wait than from LetsGetChecked, but it’s about 11 days faster than getting results from Paloma.

Also similar to LetsGetChecked are Everlywell’s tiered subscription options. If you plan on re-testing your thyroid biomarkers on a regular basis, then you can get your test kits at a discounted rate:

• Monthly for $111 (25% off)
• Quarterly for $119 (20% off)
• Semi-annually for $126 (15% off)

If your results come back in a way that suggests hypo- or hyperthyroidism, then you’ll qualify for ongoing physician support and prescriptions (if recommended). This additional support is available in 49 states, with the exception of New York. And the company accepts most health insurance.

Like many of the companies in this guide, Everlywell offers much more than just thyroid testing. To learn more about Everlywell and the other telehealth services it provides, check out our full Everlywell review.

One of the things that sets myLAB Box apart from the competition is how it bundles its variety of tests. While the company offers individual kits for a wide range of conditions and concerns, its targeted bundles, like the Sleep and Stress Test or Anti-Aging Test, are part of what makes myLAB Box unique.

The testing process with myLAB Box is nearly identical to Everlywell’s and Paloma’s — the sample collection is done via dried blood spot testing. The main difference is that you’ll have to fill out a laboratory requisition form in addition to completing the test itself. LetsGetChecked requires you to fill out some information on the front of the biohazard bag, but myLAB Box is really the only test mentioned in this guide that has this specific requirement for its test kits.

myLAB Box offers a standalone Thyroid Screening Test ($125 or $112.50 with a 6-month subscription) that measures TSH, T3, T4, and TPO/TPX. Though this test evaluates your levels of key thyroid hormones, it’s more expensive than our choice for the most comprehensive Thyroid Antibodies option from LetsGetChecked ($119). Additionally, myLAB Box offers neither consultations with medical professionals nor prescriptions, making the higher cost a bit difficult to justify at this time. Also, the results are less user-friendly and will actually expire after 60 days — a limitation we haven’t seen from other competitors.

However, something we do appreciate about myLAB Box is its accessibility to people under the age of 18. Every other company in this guide will only provide services to adults, but anyone 14 years of age and older can take advantage of a myLAB Box test kit, including ones that measure thyroid hormones.

Besides the Thyroid Screening Test, there are other myLAB Box tests that measure TSH, T3, or T4 as part of a larger picture of your health. If your thyroid investigation has more to do with a particular problem — like weight control or aging, some of these bundles might be worth a look. Here’s a breakdown of the various myLAB Box tests that feature thyroid biomarkers, along with their single-purchase prices:

Best in-lab test

Some people may prefer to test in a controlled lab setting and not administer a test themselves. HealthLabs provides a fairly comprehensive array of in-lab thyroid tests that you can have completed at one of many Labcorp or Quest Diagnostics locations (or even a mobile blood draw in some locations for an additional $119). HealthLabs offers both panels and single-measurement tests, so you can choose exactly what you want to have tested (or not tested). The company’s thyroid-specific tests include:

• Thyroid Panel ($39)
• Thyroid Panel with TSH ($59)
• TSH Test ($39)
• Thyroid Peroxidase Antibodies Test ($79)
• Thyroid Stimulating Immunoglobulin Test ($119)
• Total T4 Test ($49)
• Free T4 Test ($39)
• Free T3 Test ($99)
• T3 Test ($39)
• Reverse T3 Test ($59)

As you can see, the Thyroid Panel with TSH is likely the best deal if you’re looking for something similar to what’s offered by the at-home tests from companies like LetsGetChecked or Paloma Health.

HealthLabs’ Thyroid Panel with TSH examines your:

• T4
• T3 uptake
• T7 (A calculation of T4 and T3 uptake used to estimate free T4)
• TSH

The downside to the structure of HealthLabs’ thyroid testing is that the thyroid panels don’t test specifically for total T3 or free T4. Rather, free T4 is estimated using T7, which utilizes T3 uptake (and may be considered obsolete since the development of tests for T4 and thyroxine-binding globulin).17 For more direct measurements of total T3 and free T4, you might have to purchase the single-item tests for those biomarkers, specifically.

In terms of similar services, Walk-In Lab also offers lab orders for a multitude of thyroid blood tests. Like HealthLabs, these orders can be carried out at both Labcorp and Quest locations. However, Walk-In Lab’s prices can vary depending on your lab of choice, and the most similar test option to HealthLabs’ Thyroid Panel with TSH (Thyroid Test #1 Baseline) costs $10-$20 more either way.

The most significant difference among these tests is having to go get an in-person blood draw using an order purchased from HealthLabs, or staying home and performing the sample collection yourself using the supplies provided by our other at-home test picks. Below, we delve further into the testing experiences of both.

Testing in a lab

If you place an order with HealthLabs, you’ll have the opportunity to select a Labcorp or Quest lab in your area. Depending on where you live, you may have several labs to choose from, or even the option to add on a mobile blood draw for $119.

Usually, within 30 minutes of your order (if you don’t have to fast for the test), you can visit the lab as a walk-in and wait for an opening to have your sample collected. This wait varies significantly depending on location and time of day, so you may prefer to make an appointment with the lab and go in at your chosen date and time. And some locations may specify that appointments are necessary (such as some of the Labcorp locations within Walgreens). Many Labcorp and Quest locations offer same-day appointments.

The blood draw itself usually takes just a few moments, and you’ll need to keep a cotton ball taped to the injection site for 30 minutes afterward. From that point, all you have to do is wait. Within 1-3 business days, you’ll receive an email telling you your results are ready, and you can log into your account on the Healthlabs website to view them. A printable PDF is available (similar to all of our other at-home test picks), and you can call the company to speak with a medical expert if you have any pressing questions about your results.

Testing at home

Testing from home requires a little more patience, as you’ll usually wait 2-5 days for your test kit to arrive in the mail. And if it comes on a Thursday or Friday, you’ll want to wait until Monday to take the test — this is because weekend postal delays could theoretically be long enough that your sample might become non-viable. It’s a slim chance, especially given the durability of the blood spot tests most of these companies use, but it isn’t a chance worth taking. LetsGetChecked avoids this risk entirely by using UPS's next-day air shipping instead of the postal service.

The kit itself will contain instructions, and every kit we mention here asks you to go online and register your test before doing anything else. This is an advisable practice to ensure that you don’t forget to do it later, which would make your sample impossible for the lab to track.

Each kit provides a different location for you to find your unique registration code: Paloma’s is inside the box lid, Everlywell’s is front and center on a cardboard insert that’s visible right when you slide the sleeve off the kit, and both myLAB Box and LetsGetChecked have codes on cards included inside the test kit materials.

After you register, you can prepare the area you intend to use for your collection. It’s ideal to make this area as clean and uncluttered as possible. You’ll then want to wash your hands thoroughly with soap and warm water, then review the instructions for blood collection. All of the kits come with instructions in some form, but the collection process is basically the same for all of them (with the exception of LetsGetChecked).

Most will go like this: Press the lancet into the side of the tip of your least important finger. For many people, this is the ring finger on your non-dominant hand. Additionally, some tests will actually instruct you on which fingers to use — LetsGetChecked’s instructions state to use only the ring and middle finger on one hand, meaning you shouldn’t swap hands in the event of needing to poke a second finger.

For dried blood spot testing, try to make sure to let the blood droplets fall onto the paper within the marked circles. (You don’t want to touch the paper with your finger, as this could contaminate your sample.) You’ll then need to let the paper dry for at least half an hour or more, depending on the instructions, before packing it up in the biohazard bag and prepaid envelope, shipping it off, and waiting for your results.

When collecting a sample using LetsGetChecked’s vials, we recommend running your selected fingers (you’re likely to need to use both) under warm water for a few minutes, moving around a bit to get your circulation pumping, and finding a surface to place the vial that allows gravity to work in your favor. Keeping your hand below your heart, at the very least, should help the blood flow a little easier.

Most companies give you some indication that your sample has shipped, and both LetsGetChecked and Paloma include a timeline on your account dashboard where you can monitor the status of your sample.

Generally, samples yield results within about 2-5 business days after arriving at the lab (the longest our testers waited for results after a sample was received was six days from Paloma). As with in-person testing, you’ll receive an email or text message directing you to your online account, where you can view and download your results.

At-home blood collection tips

After trying out a wide variety of at-home testing kits from several different companies, our testers compiled a selection of tips to help make your at-home blood draw experience run as smoothly as possible — no matter the test you choose.

1. Before puncturing your finger, run it under warm water for several minutes to promote better blood flow.
2. If you feel comfortable doing so, skip the alcohol wipe. It can dry out your skin, which may lead to poor blood flow and more pain after drawing. In place of the wipe, washing your hands thoroughly with soap can be a good alternative (especially if you’re already going to be running them under warm water anyway).
3. Unless it proves to be difficult or inconvenient, consider standing up while you’re collecting your sample to get a better flow to your hand. Having your hand below your heart is ideal.
4. While it can be tempting if your blood flow is slow or inadequate, try to avoid squeezing or “milking” your finger to get more blood. Another option is to hold your hand above your head for about three seconds, then drop it down. For some testers, this helped to make some more blood come out. If that fails, you’ll likely be in less pain later by just pricking a second finger than you’d be if you tried milking (which can cause bruising).

If you’re new to the world of thyroid health, then all of the different hormones, their purposes, and the terminology surrounding them may be confusing. Even the small differences between tests for the same hormone can be complicated. In this section, we break down what your results may mean. Of course, it’s best to consult your primary care doctor or endocrinologist for interpreting your specific case, but this information can give you a general idea of what your results could indicate (if anything).

Thyroid-stimulating hormone (TSH) testing

Your TSH level is a crucial measurement — it’s often the first hormone doctors evaluate when investigating a potential thyroid problem. High levels of TSH may suggest that the thyroid is underactive due to an issue affecting the gland directly. Conversely, low levels of TSH can indicate that the thyroid is overactive.4

This may be due to a problem affecting the thyroid directly or a problem affecting pituitary gland function.4 There is quite a bit of important insight that a TSH measurement alone cannot provide. For example, a TSH blood test alone also can’t determine if your immune system is attacking your thyroid, or if you’re deficient in minerals and vitamins needed for thyroid health. That’s where thyroid antibody tests and vitamin panels can come into play.

Additionally, measuring the T4 and T3 values in a thyroid panel gives doctors much more information that can help them arrive at a diagnosis more quickly. The three values together (TSH, T4, and T3) provide a baseline for understanding whether a thyroid disorder exists.19

Thyroxine (T4) testing

The thyroid hormone thyroxine, or T4, circulates in the blood in two forms:5

• Bound T4: Attached to proteins and consequently prevented from entering cells.
• Free T4: "Free" from proteins and able to enter cells as necessary.

Measuring free T4 (fT4) together with TSH is most useful when assessing the function of the thyroid. Doctors tend to test for free T4, as it’s considered more accurate than measuring total T4 (which is both free T4 and bound T4).5

Low fT4 alongside high TSH could signal hypothyroidism (underactive thyroid).5 11 This type of test result suggests that the pituitary gland is producing more TSH to signal to your thyroid gland that it ought to make more T4. Yet, despite this, the thyroid is not producing enough T4 to reach normal levels.

Meanwhile, if your TSH level is elevated, but your levels of T4 and T3 are normal, you might have what is known as subclinical hypothyroidism.20

If your T4 and T3 levels are above normal, while your TSH level is low, you may have hyperthyroidism (overactive thyroid). In this case, your pituitary gland is not telling the thyroid to produce more T4, and yet the thyroid is producing excessive amounts of it.21

Triiodothyronine (T3) testing

Like T4, triiodothyronine can be found in your blood in both free and bound forms. Very little of your body’s T3 actually comes from the thyroid — most T3 is made by your body converting T4 into T3.3 22

T3 tests are often used in combination with T4 and TSH testing to determine the severity of hyperthyroidism (overactive thyroid). The higher the levels are, the worse the thyroid is overproducing. It is rarely helpful in diagnosing hypothyroidism, as the levels of T3 are often stable in that condition.22

Thyroid antibody testing

When TSH, free T4, and T3 results suggest a disorder, the next step is a further diagnostic workup to identify the underlying cause. This additional testing often includes a blood sample to measure common thyroid antibodies such as thyroid peroxidase (TPO/TPEX) and thyroglobulin (TgAb), in addition to other exams.7

The measurement of thyroid antibodies can determine if the thyroid is under attack from the immune system. Your immune system protects your body against foreign invaders by sending antibodies to destroy them. These antibodies come from white blood cells known as lymphocytes, and they sometimes target the thyroid. In individuals with hypothyroidism or hyperthyroidism, lymphocytes often produce antibodies that stimulate or damage the thyroid.7

Two common ailments detectable with the help of antibody testing include the following.

• Hashimoto’s disease — also called Hashimoto’s thyroiditis — is an autoimmune disease in which your own body’s immune system attacks your thyroid, leading to hypothyroidism. The TPO/TPEX and TgAb antibodies may show up alongside low free T4 and elevated TSH.23
• Graves’ disease is an autoimmune disease that causes hyperthyroidism (in which the thyroid produces too much T4). With Graves’ disease, TPO/TPEX will often show up in the blood, in addition to the other signs of hyperthyroidism presented by TSH, T4, and T3 levels.24

Thyroid tests that measure TSH, free T4, T3, and thyroid antibodies provide an excellent window into the functioning of the thyroid gland and the potential underlying causes of abnormal test results.

Challenges associated with testing thyroid function

The perfect thyroid test would analyze the levels of thyroid hormones in all of the body’s cells. Unfortunately, this is not possible. Instead, we have to infer information about hormone levels in the cells by measuring levels in the blood. While blood tests can usually analyze the amount of thyroid hormones in circulation, there are limitations.

The difficulties with thyroid testing are often a result of this indirect measuring not effectively communicating complex interactions and processes at a cellular level. For example, the body cells might not be actively taking in the hormones if the receptors have become resistant.25 This would mean the blood levels of the hormone would appear normal but may still cause unpleasant or dangerous symptoms.

If you suspect you might have a problem with your thyroid, a doctor will investigate by recording your symptoms and examining your neck to feel if your thyroid might be enlarged. This can be a good indicator of thyroid disease.