T3 is an active thyroid hormone that your body creates by converting thyroxine (T4) into triiodothyronine.
The 3 and 4 in the names represent the number of iodine atoms it has.
The T3 test simply measures how much of this hormone is present in your blood.
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If the level is either abnormally high or abnormally low, it can be an indicator of thyroid disease.
Purpose of Test
Thethyroidis a butterfly-shaped gland in the front of your throat.
Your healthcare provider may choose to perform a separate test for free T3.
Tests to look for antibodies that indicate autoimmune thyroid disease, includingHashimoto’s thyroiditisandGraves' disease.
The T3 test, as well as other thyroid tests, are performed on blood samples.
The process for drawing blood for these tests is generally quick, simple, and low-risk.
Let your healthcare professional know if you feel any of these symptoms.
Usually, this can easily be handled by laying down for a few minutes and hydrating with water.
They should be able to mitigate any risk these factors create.
Some medications can interfere with thyroid hormone levels and test results.
Timing and Location
The blood draw itself shouldn’t take more than a few minutes.
If you’re getting a lot of tests done, it could take slightly longer.
Some healthcare provider’s offices may perform the blood draw in conjunction with an appointment.
In that case, it should add very little time to the appointment length.
Going to a lab for the test can take more time.
Labs are often busy and wait times may vary.
If you’re dropping in, it can be a good idea to call ahead of time.
Certain times of day, especially first thing in the morning, may be better than others.
What to Wear
You should be able to stay in your own clothing during the test.
Food and Drink
Any time you’re having blood drawn, you should be sure you’re well hydrated.
It will make your veins easier to find and help avoid problems with needle insertion.
It may help you avoid becoming nauseous.
Remember that other tests ordered at the same time may require fasting or other special instructions.
Be sure to follow all of the instructions you’re given to ensure accurate test results.
Laboratory costs for a total T3 test can range from $35 to around $100.
A full set of thyroid tests may cost $500 or more.
This is to confirm everything is labeled correctly.
Pre-Test
Once you’ve exposed your arm, the insertion area will be cleaned with alcohol.
You may be asked to pump your fist to help with this process.
Depending on how many tests are ordered, they may need to change vials one or more times.
Post-Test
Most of the time, you’re able to leave right away after your blood is drawn.
If you have any problems or questions, contact your healthcare provider.
You shouldn’t have any other lingering effects.
Often, they can be managed by taking medication and possibly making a few dietary changes.
American Thyroid Association.Thyroid Function Tests.
MedlinePlus.Triiodothyronine (T3) tests.
2018;8(1).
