The thyroid is a small gland with two lobes connected by a bridge of tissue that sits below the larynx at the front of the neck. Although not big in size, the thyroid gland plays a major role in ensuring the proper function of the brain, heart, kidneys, liver, and skin. For this reason, it is important to learn if your thyroid is not functioning correctly as soon as possible.
It is estimated that 20 million Americans have some form of thyroid condition, with up to 60 percent of them unaware they have the disease. It is a relatively common disease that disproportionately affects women and people over the age of 50. Women are around five to eight times more likely to have thyroid problems, with one in eight developing thyroid disease during her lifetime.
Not many people realize that it is now entirely possible to test the functioning of your thyroid in the comfort of your own home via convenient testing kits that you can order online. The purpose of this guide is to explain:
- How to test for thyroid problems at home
- What your best testing options are, along with our recommendations
- Why a well-functioning thyroid is so important to your well-being
- The symptoms of thyroid disorders.
There are now many companies that have perfected the ability to deliver state-of-the-art thyroid test kits to your home and then evaluate the sample with outstanding accuracy upon its return. From your many options, two testing companies stood out among the rest: LetsGetChecked and Everlywell.
What is the best at-home thyroid test?
Summary of our recommendations:
Both at-home thyroid tests offered are highly recommended and check all of the boxes.
LetsGetChecked is a respected at-home testing company that receives high ratings in terms of Value, Accuracy, Privacy, and Customer Support.
Current Deals: Save 20% with coupon code: INNERBODY
LetsGetChecked is our top choice provider of at-home thyroid tests for the following reasons:
- The company only partners with lab facilities that are CLIA, INAB, CPA, or CAP-certified
- It offers free phone consultation with a registered nurse if you test positive for specific medical conditions
- Live online chat is available to answer pre-purchase questions
- For a limited time, all Innerbody readers can save 20% off all tests by using the promo code: INNERBODY
- Review Summary
- Why you should trust us
- LetsGetChecked Thyroid Test & Thyroid Antibody Test
- Everlywell Thyroid Test
- How do we choose our recommendations?
- Understanding how the thyroid gland works
- How are thyroid hormones regulated?
- What can go wrong with the thyroid?
- What are the symptoms of thyroid disease?
- Understanding how thyroid tests work
- Challenges associated with testing thyroid function
- Interpreting testing results
Innerbody.com recently celebrated its 20-year anniversary online. Over the past two decades, we have helped tens of millions of readers make informed decisions involving staying healthy and living healthier lifestyles. Our testing team has purchased and compared over 500 health-related tests to date, and we are constantly updating our guides based on the latest test advances. The primary author of this guide is a former Influenza Virologist who has a PhD in Microbiology and Molecular Genetics. Like all medical-related content on this website, this guide was thoroughly vetted by one or more members of our Medical Review Board for medical accuracy.
The LetsGetChecked Thyroid Test [see latest price] evaluates thyroid function via analysis of three biomarkers: thyroid stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4). The more comprehensive Thyroid Antibody Test [see latest price] includes analysis of these three biomarkers in addition to two more: thyroglobulin antibodies (TGAB), and thyroid peroxidase antibodies (TPEX). Information on the significance of your levels of each of these biomarkers and how to interpret your results is included with your report.
The main difference between the two kits is that the TGAB and TPEX antibody testing in the Thyroid Antibody Test can tell you whether your thyroid dysfunction is likely to be related to an autoimmune disorder. The basic Thyroid Test kit can tell you that there may be an issue with your thyroid but cannot tell you the cause.
If you are in doubt as to which one to choose, we recommend going with the basic Thyroid Test. If results turn up anything, follow up with your doctor and take a more comprehensive test at her or his discretion.
Our second-choice recommended testing company is Everlywell.
Everlywell’s popular Thyroid Test [see latest price] evaluates thyroid function via analysis of four hormones: thyroid-stimulating hormone (TSH), TPO, T3, and T4. Symptoms associated with a malfunctioning thyroid include sluggishness, high blood sugar, high cholesterol, unexpected or unusual weight gain (or loss), depression, and more. We generally like this test as it provides a sound reason to visit your healthcare provider in the event that your test results show any abnormalities. If for whatever reason you did not want to go with LetGetChecked, Everlywell offers a solid alternative to LetGetChecked’s basic Thyroid Test.
We customize our evaluation criteria depending on the type and nature of the test. For most health-related tests, we have five areas that we use for our evaluations, including:
Accuracy: Do the testing companies use the latest and most accurate testing technologies available? How accurate are the tests compared to alternatives?
Value: Are you getting your money’s worth? Are there any hidden costs or charges? Does the test provider offer discounts to our readers?
Customer Support: How well does the testing company help you choose the best test? How clearly are the results presented? How well does the testing company help you understand results and get treatment if necessary?
Privacy: Are all test kits sent in discreet packaging? Will your data be stored securely? Could your data ever be shared without your permission?
Test Results Speed: How fast will you receive your test results from the moment you click “buy?” Are the waiting times stated by the testing companies accurate and consistent?
The thyroid is an endocrine (hormone-secreting) gland in your neck with a number of different functions, most notably regulating your metabolic rate.
The production of thyroid hormones is controlled by thyroid-stimulating hormone (TSH) and thyrotropin-releasing hormone (TRH).
TSH is produced and released into the blood by the pituitary gland. This hormone then binds to the receptors on thyroid cells and causes them to produce T3 and T4. The more TSH being secreted, the more thyroid hormones are secreted. The pituitary detects the levels of these hormones in the blood.It will reduce the secretion of TSH if the concentration of thyroid hormones is too high, or increase the production of TSH if the concentration of thyroid hormones is too low.
The pituitary gland itself is regulated by a part of the brain known as the hypothalamus. The hypothalamus produces thyrotropin-releasing hormone (TRH), which stimulates the pituitary gland to produce TSH.
The hormonal regulation of the thyroid can be imagined as a little like a thermostat. When the room gets too hot, the thermostat signals to the radiators to stop producing heat. When the room gets too cold, the thermostat signals to the radiators to produce more heat. This constant signaling and responding keeps the room at a stable temperature.
However, abnormal levels of TSH, T3, and/or T4 throw the carefully balanced system out of tune.
Problems with the thyroid usually result in the overproduction or underproduction of thyroid hormones and/or TSH.
The overproduction of thyroid hormones, known as hyperthyroidism, can be caused by conditions such as Graves’ disease (the production of too much thyroid hormone), toxic adenomas (nodules developing in the gland which secrete extra thyroid hormones), subacute thyroiditis (inflammation of the thyroid that results in the leaking of extra hormones), and dysfunction of the pituitary gland regulating the action of the thyroid and causing excess production of thyroid hormones.
Hypothyroidism is the underproduction of thyroid hormones. This can be caused by Hashimoto’s thyroiditis (an autoimmune disorder where the thyroid tissue comes under attack from the body’s immune system), and exposure to toxic levels of iodine.
If the thyroid is producing too much T3 and/or T4 (hyperthyroidism), the cells of the body are working too fast, and this can speed up bodily functions. This can lead, for example, to a faster heart rate, more frequent bowel movements, or even diarrhea.
Common symptoms of hyperthyroidism include:
- weight loss
- increased appetite
- excessive sweating
- rapid heart rate
- intolerance to heat
- frequent bowel movements
- hair loss
- missed and/or light menstrual periods
If not enough T3 and/or T4 is being produced (hypothyroidism), the cells of the body slow down. This can slow the heart rate and cause bowel movements to become less frequent.
Common symptoms of hypothyroidism include:
- weight gain
- sleeping and concentration difficulties
- dry skin and hair
- joint and muscle pain
- intolerance to cold temperatures
- frequent and/or heavy periods
Most thyroid tests use blood to measure the amount of hormones circulating in the body. However, these can be used alongside other tests to get more detailed information about the disorder.
The TSH level in the blood sample is often the first hormone measured when investigating a potential thyroid problem. High levels of TSH suggest that the thyroid is underactive as a result of a problem affecting the gland directly. Conversely, low levels of TSH suggest that the thyroid is overactive. This may be due to a problem affecting the thyroid directly, or a problem affecting the function of the pituitary gland, which in turn is affecting the thyroid.
The thyroid hormone T4 circulates in the blood in two forms: bound to proteins and prevented from entering cells, or free and able to enter cells. Measuring free T4 (FT4) can be used to assess the function of the thyroid, with higher levels indicating hyperthyroidism, and low levels indicating hypothyroidism.
The TSH test is often combined with the FT4 test, as the two tests together can usually give a more precise understanding of thyroid function. High levels of TSH and low levels of FT4 usually indicate primary hypothyroidism due to a disease of the thyroid, while low levels of TSH and low levels of FT4 suggest a problem involving the pituitary gland. However, low TSH levels and high FT4 are indicators of hyperthyroidism.
T3 testing is usually used in combination with the above tests to determine the severity of hyperthyroidism. The higher the levels are, the worse the thyroid is functioning. It is rarely helpful in the diagnosis of hypothyroidism, as the levels of T3 are often normal in that condition.
Thyroid antibody testing
The measurement of thyroid antibodies can determine if the thyroid is under attack from the immune system. The immune system protects the body against foreign invaders such as bacteria by sending antibodies to destroy them. These antibodies are made from white blood cells known as lymphocytes and sometimes target the thyroid.
In individuals with hypothyroidism or hyperthyroidism, the lymphocytes are often producing antibodies that stimulate or damage the thyroid. The two that are most commonly directed against thyroid cells are thyroid peroxidase and thyroglobulin. This could indicate Hashimoto’s thyroiditis (positive anti-thyroid peroxidase and hypothyroidism) or autoimmune thyroid disease if the antibodies are present in a hyperthyroid patient.
Often, interpreting the results of several tests can offer the most accurate diagnosis.
The perfect thyroid test would analyze the levels of thyroid hormones in all of the body’s cells. Unfortunately, this is not possible. Instead, information about the levels of the hormones in the cells must be interpreted by measuring the levels in the blood.
The difficulties with thyroid testing are often a result of this indirect measuring not being effective at communicating complex interactions and processes at a cellular level. For example, the cells of the body might not be actively taking in the hormones, as the receptors have become resistant. 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. Usually, blood tests are taken to analyze the amount of thyroid hormones in circulation.
Modern TSH testing is very accurate and can detect incredibly low levels of the hormone. For this reason, it is often seen as the gold standard in thyroid diagnostics. However, there is some important information that this test does not provide. For example, the TSH blood test does not give any information on the amount of T4 being converted into T3, or if the T3 receptors are resistant to the T3 hormone. The TSH blood test also can’t tell if the thyroid is being attacked by the immune system, or if the body is deficient in the minerals and vitamins needed for thyroid health. Therefore, even if the levels of TSH appear normal in a blood test, if symptoms are present it is valuable to consider further testing options.
The interpretation of thyroid blood tests can also be problematic. Reference ranges are used to determine low, normal, or high levels of thyroid hormones. While these are based on a wide range of studies, what is “normal” to the population is not necessarily “normal” to the individual. Each person has a different hormonal and chemical composition, and deviations from normal references may be normal for the individual. Additionally, because these references have been calculated using statistics and are based on averages, the closer the test results are to either the lower or higher limit, the greater the uncertainty whether the patient has thyroid disease. Likewise, if results are within the reference range but close to the limits, symptoms may still be present.
For these reasons, blood tests should be seen as a way to confirm a diagnosis made based on the wide clinical picture, including symptoms, medical history, physical examination, and thyroid gland ultrasound. They should not be dismissed as normal without consideration of other factors.