Free T3 Test

5.0

Learn more about your thyroid function with a free T3 test.

A free T3 test measures the level of free triiodothyronine (T3) in your blood. T3 is a hormone produced by the thyroid gland that regulates metabolism, energy levels, ... Read More

$89

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Free T3 Test

$89

Test Details

Sample Type: Blood

Collection Method: In person at a Labcorp location

Age: 18+

Results: Within 1-2 days from when your sample arrives at our lab

HSA/FSA: Accepted

Test must be taken by purchaser

Preparation: If you’re taking a supplement containing biotin (also called vitamin B7 or B8, vitamin H, or coenzyme R), commonly found in products promoting nail, skin and hair health, it is recommended that you wait at least 72 hours from your last dose before sample collection.

What's Tested

Free T3

Free T3, or triiodothyronine, is a hormone produced by the thyroid gland that plays a crucial role in regulating metabolism, heart function and overall energy levels. This test measures the amount of free T3 in the blood, which is the active form not bound to proteins. A free T3 level helps assess thyroid function and evaluate conditions such as hyperthyroidism (too much thyroid hormone) or pituitary disorders. Elevated free T3 levels may indicate an overactive thyroid, which can lead to symptoms such as irregular heartbeat, weight loss, anxiety and fatigue.

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Gain clarity on unexplained thyroid symptoms

You may want to consider testing your free T3 level if you are experiencing symptoms of hyperthyroidism such as fatigue, trouble sleeping, weight loss or mood changes. A free T3 test can help you and your healthcare provider evaluate symptoms and conditions related to T3 levels.

Anxiety, nervousness, irritability
Weight loss, even though your appetite may increase
Shaky hands, muscle weakness
Sweating or being very sensitive to heat
Irregular heartbeat (arrhythmia)
Frequent bowel movements
Goiter (an enlarged thyroid gland)
Trouble sleeping and fatigue

Take control of thyroid health

A free T3 blood test allows you to see how well your thyroid is producing the active hormone that drives energy, metabolism and mood, empowering you to make informed decisions for better health and well-being.

Understand your metabolic health

Thyroid hormones T4 and T3 play a key role in regulating your metabolism. A free triiodothyronine (T3) test may help uncover how your thyroid is impacting your cells and your metabolism.

1. Medline Plus. Triiodothyronine (T3) Tests. Accessed October 9, 2024. https://medlineplus.gov/lab-tests/triiodothyronine-t3-tests.

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Purchase Your Test

Simply purchase this test online. A healthcare provider will review and approve your test requests; no healthcare provider visit is required.

Provide Your Sample

Visit a Labcorp location near you for sample collection. Visits may be scheduled online.

Get Your Results

View your easy-to-read results online in your Labcorp Patient™ account, including Linked Accounts. For certain results that require prompt attention, you will also be contacted by phone or mail.

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Find a Location Near You

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FAQ

The T3 free test measures the level of free T3 in the blood to evaluate thyroid function. Free T3 is the active form of the hormone that is not bound to proteins and can directly influence the body's processes. Understanding free T3 levels can help assess thyroid function. Abnormal T3 levels are often associated with conditions such as hyperthyroidism or pituitary disorders.

By measuring free T3 levels alongside other thyroid hormones like TSH and free T4, you and your healthcare provider can get a more complete picture of your thyroid health.
Elevated free T3 levels may indicate hyperthyroidism. You may need a free T3 test if you have symptoms.¹ Symptoms may include:

Anxiety, nervousness, irritability
Weight loss, even though your appetite may increase
Shaky hands, muscle weakness
Sweating or being very sensitive to heat
Irregular heartbeat (arrhythmia)
Frequent bowel movements (poops)
Goiter (an enlarged thyroid gland)
Trouble sleeping and fatigue
The normal range for free T3 levels may vary depending on the laboratory that performs the test, as well as age and sex. Your test results will include Labcorp’s reference range for the free T3 test. In general, a normal range of free T3 for healthy adults is between 2.0-4.4 pg/mL.

It is important to note that ranges will vary slightly from person to person, and your healthcare provider will consider your overall health, symptoms and test results when interpreting your levels. It is recommended to consult with a healthcare provider if you have any questions about your results.
Your results will be provided to you through our secure online portal to view or print. Results are also made available through a secure portal to the independent healthcare provider who placed your test order. If you are accessing your results through your Labcorp Patient™ account, all users linked to the account will have access to all OnDemand test results. Results may also be provided to a local, state, and/or federal health authority; for example, many states require the testing laboratory and physician to report test results for certain communicable diseases, such as COVID-19, to local or state health departments.

If you have questions or comments regarding the Labcorp Notice of Privacy Practices, or have a complaint about our use or disclosure of your PHI or our privacy practices, please contact: privacyofficer@labcorp.com, call us at (877) 234-4722 (877-23-HIPAA) and ask for the Labcorp HIPAA Privacy Officer, or send a written request to: HIPAA Privacy Officer, Labcorp, 531 South Spring Street, Burlington, NC 27215. You also may file a complaint with the Secretary of the U.S. Department of Health and Human Services.
Visit the Labcorp OnDemand® website to browse and purchase laboratory tests and create your Labcorp Patient™ account to view your results. All Labcorp OnDemand testing requires an order from an authorized healthcare professional. For your convenience, Labcorp OnDemand has contracted with independent professional entities (collectively, Providers) to deliver healthcare provider services. Visit a Labcorp location for sample collection; or, if using an at-home collection kit, collect your sample yourself. We’ll let you know when your results are ready and can be accessed through your Labcorp Patient™ account.

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Free T3 Test

Learn more about your thyroid function with a free T3 test.

Test Details

Why Consider This Test