Reverse T3 Blood Test
Test Code: 070104
Specimen Type: Blood
Reverse T3 Blood Test (Labcorp)
The Reverse T3 (RT3) test measures the inactive form of the hormone T3 or Triiodothyronine. Certain conditions may cause the body to convert T4 into Reverse T3 instead of active T3 as it normally does. Elevated levels of Reverse T3 are common in people with hypothyroidism. Reverse T3 is not regularly checked as often as other thyroid hormones but may be tested when someone is experiencing symptoms of low thyroid production but shows normal results from other thyroid tests.
Production of Reverse T3 is typically triggered when the body is under significant stress. Conditions which can lead to RT3 production include but are not limited to:
- periods of prolonged stress
- extreme dieting
- insulin dependent diabetes
- exposure to certain chemicals or toxic metals
- liver or kidney disease
- serious injury
- chronic alcohol ingestion
- abnormally low levels of certain nutrients
While a reverse T3 test can be ordered at any time, it is typically used when someone is experiencing symptoms of hypothyroidism, especially if they have abnormal results from other Thyroid tests. This test is also available in our Thyroid Comprehensive Panel with Reverse and Free for customers who require an in-depth thyroid testing package.
Turnaround time for this test is typically 4-8 business days.
Where can I find a Reverse T3 Test near me?
Check our lab finder to locate a collection site in your area.
Note: Result turn around times are an estimate and are not guaranteed. Our reference lab may need additional time due to weather, holidays, confirmation/repeat testing, or equipment maintenance.
This Reverse T3 test has no fasting requirements.