What Can an At-Home Thyroid Test Tell You?

In a world where convenience is king, at-home thyroid tests are revolutionizing how you monitor your health. 

As you age, you may be wondering if your thyroid is still functioning optimally, and an at-home test can be a great way to see if you need to book an appointment with a specialist. Or, if you already have a thyroid condition and just want to get a quick read on how well your medication is working, an at-home test can help with that too.  

Why does this option work so well for some people? It allows you to draw a few drops of blood directly from home, saving you a trip to the lab or the doctor’s office. 

“Convenience is the number one reason patients will want to use at-home tests,” board-certified family physician Natalie Kunsman, M.D., says. Here’s what a test from a reputable testing company can and can’t tell you. 

About the Expert

Natalie Kunsman, M.D. is a board-certified family physician and a functional medicine physician based in Colorado Springs, CO. She’s a medical advisor to Hone Health and an integrated health advisor and physician at Broad Health, Hone Health’s partnered medical practice. She also specializes in thyroid health.

Who Needs a Thyroid Test?

There isn’t a standard recommendation for how often American adults should have their thyroid tested. For example, the American Thyroid Association recommends everyone over 35 should have a thyroid test every five years (1). Conversely, the United States Preventive Services Task Force has no recommendation for screening thyroid dysfunction in nonpregnant adults with no symptoms (2). 

As a functional medicine physician, Kunsman recommends having your thyroid screened annually. This is especially true if you have symptoms like tiredness, weight gain, or changes in hair, all of which could be signs of an over- or underactive thyroid (hyperthyroidism or hypothyroidism).  

It’s also important to note that common thyroid symptoms may be caused by something bigger, such as autoimmune diseases, including Hashimoto’s and Graves disease, or thyroid cancer (3, 4). Typical at-home thyroid tests don’t screen for these causes, but they can be the first step in identifying the root cause of your symptoms.

How Do At-Home Thyroid Tests Work?

You can get an at-home thyroid test from companies like ZRT, Everlywell, and Healthyr without a doctor’s prescription—just order a test kit directly from their website. Some companies accept HSA or FSA and will even take your health insurance. Unfortunately, most charge an out-of-pocket flat fee.

While in-person labs draw blood from your veins, at-home tests typically use a fingerstick to test your blood, Kunsman says. Sometimes, at-home thyroid tests can also call for a saliva spit cup, but these results are less reliable.

The test kits are easy to use: Typically you register your test, prick your finger, collect the blood sample, and then ship it back to the lab with the prepaid shipping label.

After a few days, the testing company’s app or website will notify you of your results.

What Does a Thyroid Test Examine?

In-lab blood tests are more comprehensive than at-home kits. They can look for a range of metrics such as anti-thyroid antibodies, TPO antibodies, thyroglobulin, or other autoimmune markers, Kunsman says. At-home tests look for only a few markers, but at a minimum, they should measure TSH, free T3, and free T4.

TSH

Your level of thyroid-stimulating hormone, or TSH, indicates how well your thyroid gland is working. The pituitary gland makes TSH, which then tells your thyroid gland how much thyroid hormone it needs to make. When your thyroid hormone levels are low, the pituitary gland makes larger amounts of TSH. When thyroid hormone levels are high, the gland makes less TSH (5).

T3

Triiodothyronine (T3) is one of the two main types of thyroid hormone that helps to control your metabolism. Free T3 is the type of T3 in your blood that isn’t bound to proteins and can bind to receptors and act on cells.

T3 is one-half of the hormones collectively referred to as “thyroid hormone.” It works in conjunction with T4 and is the active form of thyroid hormone, which means it directly impacts the cells in your body. T3 is key to regulating your metabolism, heart and digestive, and muscle functions. Higher-than-average levels of T3 in your blood may be a sign of hyperthyroidism (6).

T4

Thyroxine, better known as T4, works in conjunction with T3 to make thyroid hormone, which your thyroid gland releases to regulate bodily functions such as metabolism and growth. Free T4 is the type of T4 in your blood that isn’t bound to proteins and can bind to receptors and act on cells. T4 is inactive, but most of it is converted into T3 by your liver and kidneys. If your blood tests show higher-than-normal levels of T4, this could signal hyperthyroidism or thyroid inflammation (thyroiditis) (7). 

TPO Ab

Not every at-home test looks beyond the baseline markers of TSH, free T3, and free T4. However some, like Everlywell and ZRT, also measure thyroid peroxidase antibodies (TPOAb). Antibodies are proteins that your immune system makes. TPOAb, combined with abnormal thyroid hormones, can be a sign an autoimmune disease, like Hashimoto’s Disease, is driving your hypothyroidism (8). 

How to Understand Test Results 

Once your results are in, most at-home tests will give you the results with an explanation of what they mean in the app. The best at-home thyroid tests will also offer one-on-one video chats with a board-certified doctor to answer any questions you have and also suggest an action plan based on the results. This may include suggested lifestyle changes and potentially medication as well.

Kunsman emphasizes how important it is to share abnormal results—or any results you’re unclear about—with your primary care physician. They can further guide you on treatment or refer you to a specialist.

Are At-Home Thyroid Tests Reliable?

“If done and transported correctly, a fingerstick can be as accurate as a venous draw,” Kunsman says. However, with at-home kits, there’s more of a risk that the sample could break down in transit back to the lab, which could negatively affect its accuracy. Luckily, most at-home testing companies go to great lengths to ensure this doesn’t happen, she notes.

The key here is to select a testing company that runs your specimens at a CLIA-certified (Clinical Lab Improvement Amendments) or CAP-certified (College of American Pathologists) lab, Kunsman explains. Both credentials ensure the labs meet rigorous standards and pass regular inspections.

The main difference between an at-home thyroid test and an in-person one is that the former can check only a handful of biomarkers, while at an in-person lab, your doctor can add on additional biomarkers. Why is this important? As we noted earlier, thyroid problems are sometimes caused by autoimmune conditions or thyroid cancer, which require extra testing and treatment, Kunsman explains.

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