Thyroid tests tell your healthcare provider how well your thyroid gland works. These tests can help diagnose conditions like hyperthyroidism, hypothyroidism, Graves’ disease, Hashimoto’s disease and thyroid cancer. Types of thyroid tests include blood tests, imaging tests and nuclear medicine tests.
Thyroid tests check to see if your thyroid gland works like it should. Your thyroid is a butterfly-shaped gland in your neck that sits just above your sternum (breastbone). It produces hormones that control several different body systems. It’s like a command center that manages how your body uses energy.
You might need a thyroid test if you have symptoms like fatigue, sluggishness, restlessness, irritability or unexplained weight changes. Thyroid tests can help diagnose thyroid diseases like:
Other names for thyroid tests include thyroid function tests and thyroid symptom tests.
There are several different types of thyroid tests, but they all fall under one of two categories:
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Thyroid blood tests measure certain hormones and antibodies in your blood. Too many or too few of these hormones or antibodies might mean that you have thyroid disease.
Providers use different blood tests to measure different things:
Generally, you don’t need to do anything special prior to your test. You can eat and drink normally, unless your healthcare provider tells you otherwise.
During a thyroid blood test, a provider will take a sample of your blood and send it to a lab for analysis. Once the lab completes the testing, they’ll send the results to the provider who ordered it.
Your healthcare provider will discuss their findings with you. They might recommend additional testing if they need more information. They’ll tell you what your results mean and what comes next.
Thyroid imaging tests can give your provider more information about the size, shape and function of your thyroid gland. Providers might recommend imaging tests after you’ve already had thyroid blood tests.
Healthcare providers use different imaging tests for different reasons:
If your healthcare provider plans to use a contrast material, you might need to stop eating or drinking for a few hours before your procedure. Or, you might need to avoid kelp and other foods with a high iodine content.
Instructions will vary depending on your situation. Your provider will tell you if you need to make any special preparations.
Your radiologist will send your imaging results to the provider that ordered the test. Once they review your scans, they’ll discuss their findings and recommendations with you.
If your scans show a lump on your neck, your provider may recommend a needle biopsy, also known as FNA (fine needle aspiration). This will tell them whether the lump is noncancerous or cancerous.
Once your provider reviews your thyroid test results, they’ll call you to discuss them or schedule a follow-up office visit. In most cases, this process should only take a few days.
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Healthcare providers may run several blood tests to determine thyroid function. The two most common tests check your TSH (thyroid-stimulating hormone) and T4 or free T4 (thyroxine) levels.
Providers may also recommend a full thyroid blood test panel.
A full thyroid blood test panel measures the levels of these hormones and antibodies in your blood:
If your TSH level is high, it might mean you have hypothyroidism. This means your thyroid gland doesn’t make enough thyroid hormone.
On the other hand, if your TSH is low, it could indicate hyperthyroidism. In this case, your thyroid gland makes too much thyroid hormone.
Your healthcare provider will discuss your results and tell you what they mean for you and your health.
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There are certain things that can throw off your thyroid test results, including:
It depends on what type of test you have. Most healthcare providers don’t recommend fasting before a thyroid blood test. But for thyroid scans, especially those that require a contrast material, you may need to stop eating and drinking a few hours before your appointment.
Your healthcare provider will let you know if you need to fast or make other preparations before your thyroid test.
A note from Cleveland Clinic
Overactive and underactive thyroid can interfere with daily routines and hinder your quality of life. If you have symptoms of thyroid disease, a thyroid test can find out what’s causing them so your provider can recommend treatment.
Last reviewed on 05/30/2023.
Learn more about the Health Library and our editorial process.
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Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy