TestWell Price
$33.99
+ $6 lab processing fee
Triiodothyronine (T3) is the thyroid hormone that actually drives metabolism at the cellular level. Total T3 measures everything in circulation, most of it bound to carrier proteins; Free T3 measures the small unbound fraction that is biologically active. Read together, they distinguish a genuine change in T3 production or T4-to-T3 conversion from a shift in binding proteins, and they help explain hypothyroid or hyperthyroid symptoms when TSH and T4 alone don't tell the whole story. Most useful as part of a full thyroid workup rather than as a first-line screen.
Sample Type
Blood draw
Fasting
Not required
Results In
1–3 business days
Performed At
Quest or Labcorp
Your T3, Free & Total (Triiodothyronine) results will include values for each of the 2 biomarkers tested, along with reference ranges. Results are reviewed by a licensed physician before being released to your secure portal.
If any values fall outside the normal range, your report will include guidance on what that may mean and recommended next steps. You'll receive an email notification when your results are ready, typically within 1–3 business days.
Typical reference range layout
Lab reports show where your value sits relative to established reference intervals—your physician interprets this in context for you.
Your T3, Free & Total (Triiodothyronine) results will include values for each of the 2 biomarkers tested, along with reference ranges. Results are reviewed by a licensed physician before being released to your secure portal.
If any values fall outside the normal range, your report will include guidance on what that may mean and recommended next steps. You'll receive an email notification when your results are ready, typically within 1–3 business days.
Typical reference range layout
Lab reports show where your value sits relative to established reference intervals—your physician interprets this in context for you.
No fasting required. Biotin supplements can interfere with thyroid assays — skip them for 48 hours before your draw if possible.
No fasting required. Biotin supplements can interfere with thyroid assays — skip them for 48 hours before your draw if possible.
TestWell Price
$33.99
+ $6 lab processing fee at checkout
No insurance needed · HIPAA compliant
Frequently ordered together
Customers who ordered T3, Free & Total (Triiodothyronine) also added these for a more complete health picture.
Not sure where to start?
T3, Free & Total (Triiodothyronine)
$33.99