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.
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
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.
Explore the Apex 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.