Total triiodothyronine — bound plus free.
What is it
Total T3 includes both protein-bound and free triiodothyronine in circulation. It can be affected by changes in carrier protein levels independent of true thyroid status.
Why it's measured
Total T3 has been used in research and clinical practice, often alongside Free T3.
Reference range
Standard laboratory reference
80 – 200 ng/dL
Reference ranges vary by laboratory. Your individual reference range will appear on your test report and should be interpreted by your physician in the context of your overall health profile.
Where does your number land?
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Drag to your own Total T3 result.
Educational only, not a diagnosis. Ranges vary by laboratory. See which panel includes Total T3.
What results may indicate
Elevated
Has been associated with hyperthyroidism in research literature.
Lower
Has been associated with hypothyroidism or non-thyroidal illness in research literature.
These associations are general. They are not a personal diagnosis or prediction. Discuss your individual results with your physician in the context of your full health profile.
When it's measured
Sometimes measured in comprehensive thyroid panels.
Related markers
Common questions
Total T3 includes both protein-bound and free triiodothyronine in circulation. It can be affected by changes in carrier protein levels independent of true thyroid status.
It's one of the markers used to build a fuller picture of your health. On its own it tells you very little, so it's most informative when reviewed alongside related markers.
It's measured from a standard blood draw at Quest or LabCorp. Total T3 is one of the markers included in the OPTML Apex Panel, where your results are read across systems and reviewed by a U.S.-licensed physician.
Reference ranges vary by laboratory, and a single value rarely tells the whole story. Review your result with a physician in the context of your other markers, symptoms, and history.
Total T3 is one signal among many. Answer a few quick questions and we’ll point you to the panel that fits.
Measured in
A complete look at your heart, hormones, metabolism, inflammation, and longevity systems — drawn at Quest or LabCorp, reviewed by a U.S.-licensed physician.
Find the right panel →This information is for general educational purposes only and is not medical advice. Lab results alone are not intended to diagnose, treat, or cure any condition and do not replace the advice of a healthcare provider. OPTML does not offer medical advice, a diagnosis, medical treatment, or any form of medical opinion.
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