T3, Free Blood Test

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Feature	Labcorp	Quest Diagnostics
Price	$33.49	$10.49
Results in	~2 business days	~5 business days
Sample type	Blood Serum	Blood Serum
Require fasting	No	No

About the test

T3, Free measures the unbound, active form of triiodothyronine in the bloodstream. It is used to evaluate thyroid function, especially in diagnosing hyperthyroidism or assessing the effectiveness of thyroid hormone therapy.

Included biomarkers & Reference ranges

Biomarker	Reference range
T3, Free (fT3) The unbound, biologically active portion of triiodothyronine (T3), the more potent thyroid hormone. Used to evaluate thyroid function.	2.3–4.2 pg/mL

Reference ranges vary by lab, age, and sex (M/F). Your report shows your exact range. Click any biomarker to see its optimal range and what your results mean.

How it works

1. Order online No referral or insurance
2. Get a requisition By email in 24–72 hours
3. Visit a draw center Bring a matching photo ID
4. Get results Securely by email

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Consultations

Not sure how to read your results? We can help.

Schedule a consultation with a Hormunity specialist. We’ll walk through every marker, interpret what it means for you, and map out the next steps for your care.

Book a specialist