8 Things to Know About Routine Thyroid Tests



The butterfly-shaped gland in the front of your neck is your thyroid gland. Though it’s a small gland, the thyroid is responsible for the production of two essential hormones (triiodothyronine (T3) and thyroxine (T4) that keep your organs healthy.
To ensure that your thyroid is producing healthy levels of necessary hormones, several thyroid tests are available. Your health care provider may recommend you have a thyroid test if they suspect you may have an overactive or underactive thyroid gland. Here are 8 things to know about thyroid tests.
What are the most routine thyroid tests?
Thyroid tests, also known as thyroid function tests may include blood tests and ultrasound imaging tests. The most common thyroid tests are:
- TSH Test
- T4 Test
- T3 Test
- Thyroid Antibody Test
- Ultrasound/Imaging Test
TSH test
The TSH test is generally the first thyroid test your health care provider will order if you are showing symptoms of a thyroid condition. The TSH test is a blood test that measures the amount of thyroid-stimulating hormone (TSH) in your blood. TSH is made by your pituitary gland. It is responsible for “telling” your thyroid how much thyroid hormones it needs to make.
Do I need to prepare for the TSH test?
You do not need to do anything to prepare for a TSH test. Your blood may be drawn at any time during the day, and you won’t need to fast, or otherwise prep for the test. If your TSH test comes back within the normal range, you likely won’t need additional thyroid tests.
However, if you have high or low levels of thyroid-stimulating hormone in your blood, your health care provider may order other thyroid tests such as T4 and T3 tests.
What is the T4 test?
The T4 test measures the amount of thyroxine your thyroid produces. Thyroxine is a hormone that plays a vital role in growth and metabolism. A T4 test is a simple blood test that may be ordered if your TSH test results were abnormal. Your health care provider may order either a total T4 test or a free T4 test. Both types of T4 tests involve drawing blood and sending it to the lab for analysis.
Do I need to prepare for the T4 test?
Before your T4 test, be sure your health care provider knows of all medications you are taking, as certain medications may affect your T4 levels. Your health care provider may have you temporarily stop taking certain medications ahead of your T4 blood test.
In addition, pregnancy can alter the level of T4 in your blood, so be sure to notify your health care provider if you may be pregnant.
What is the T3 test?
The T3 test measures levels of the hormone triiodothyronine in your blood. It is performed using a blood draw. Triiodothyronine plays an important role in various processes in the body, such as your heart and digestive function. Triiodothyronine is also vital for muscle control, brain function, and the maintenance of bones.
Do I need to prepare for the T3 test?
No special preparation is necessary before having a T3 test. However, you should be sure to let your health care provider know of all medications you are taking, in case you need to temporarily stop one of them before your test. Be sure to also let your health care provider know if you are pregnant or might be pregnant.
What is the thyroid antibody test?
Antibodies are released by your body’s immune system when your body has been invaded by a virus or a bacteria. Unfortunately, your body may make antibodies that mistakenly attack your thyroid gland, which can increase or decrease the production of vital hormones.
The thyroid antibody test is a blood test to check for certain antibodies that may be impacting your thyroid. Your health care provider may order this test if you’ve had abnormal TSH tests, or if your thyroid is enlarged.
What is a thyroid ultrasound?
If your health care provider finds a growth on your thyroid gland known as a goiter, or if a thyroid blood test comes back abnormal, a thyroid ultrasound may be recommended. This painless imaging test will examine your thyroid to look for tumors, nodules, or cysts. Your health care provider may order an injection of contrasting agents, to improve the quality of the ultrasound images.
If a contrast agent is ordered for the test, you will receive a quick injection before the ultrasound scan is performed. You will likely have a gel applied to your neck before the ultrasound probe is rubbed over your skin to view the thyroid. The test only takes a few minutes, and aside from the injection of a contrast agent, the test is painless.
Do I need a thyroid test?
Your health care provider will determine whether or not you should have a thyroid test. However, women are more likely to have low levels of thyroid hormone than men, so women may be more likely to be referred for a test than men.
Your health care provider may suspect a problem with your thyroid function, and order a thyroid function test if you experience symptoms of hyperthyroidism or hypothyroidism.
How often should a thyroid test be done?
Thyroid screening is not currently a widely recommended screening test. If you have symptoms of a thyroid condition your health care provider will determine which type of thyroid test you should have, and how often it should be repeated.
When to Talk to Your Health Care Provider About Your Thyroid
If you notice swelling in the front of your neck, talk to your health care provider about it. A swollen thyroid may indicate hyperthyroidism, hypothyroidism, autoimmune disorders, or other condition. Likewise, if you have symptoms of an overactive or underactive thyroid, discuss your concerns with your health care provider. There are numerous treatments and medications available to treat thyroid conditions.
If you are prescribed medication to treat an overactive or underactive thyroid, be sure to check RxSaver. RxSaver offers savings of up to 85% on more than 6,000 medications.

Jennifer Hadley
Jen Hadley is a freelance writer and journalist based in Los Angeles, who writes extensively about the medical, legal, health care, and consumer products industries. Jen is a regular contributor to RxSaver.

Meron Hirpa, MD
Meron Hirpa, MD, is an Internal Medicine Public Health Physician at the Cincinnati Health Department. Dr. Hirpa obtained her medical degree from the University of Florida College of Medicine and completed her residency training in Internal Medicine at Johns Hopkins. She is board-certified in Internal Medicine and holds specialized training in urban health, global health, quality improvement, and health disparities. Dr. Hirpa treats a broad spectrum of illnesses in adults. She is dedicated to patient-centered care and equity and is passionate about closing the healthcare gap among different groups. Towards that end, she led award-winning diversity and inclusion initiatives in the healthcare space. In addition to treating her patients, Dr. Hirpa conducts theoretical and clinical research and publishes in academic journals. Dr. Hirpa frequently appears in radio and television programs for healthcare commentaries.
The information on this site is generalized and is not medical advice. It is intended to supplement, not substitute for, the expertise and judgment of your healthcare professional. Always seek the advice of your healthcare professional with any questions you may have regarding a medical condition. Never disregard seeking advice or delay in seeking treatment because of something you have read on our site. RxSaver makes no warranty as to the accuracy, reliability or completeness of this information.
If you are in crisis or you think you may have a medical emergency, call your doctor or 911 immediately.
READ MORE
Which Flu Shot Is the Most Effective for the 2021-2022 Flu Season?
Key takeaways: There are nine flu vaccines available for the 2021-2022 flu season. Some flu vaccines may be a better option for certain people,...
By Christina Aungst, PharmD
Can Anxiety Cause Fatigue?
Learn the signs and symptoms to look out for and what you can do to help overcome anxiety fatigue.
By Jennifer Hadley
What’s the Difference Between An Anxiety Attack and a Panic Attack
While many anxiety and panic disorders have similar symptoms, there are differences between various disorders even if they seem similar.
By Jennifer Hadley