The short answer
Measures total triiodothyronine (T3), bound and free — the thyroid hormone that rises first in many cases of an overactive thyroid, measured from a standard blood draw. At TestWell it costs $24.99 plus a $6 lab processing fee, needs no fasting, and results post in 1–3 business days. Physician-authorized with no doctor's visit or insurance needed; draw at Quest or Labcorp.
TestWell Price
$24.99
+ $6 lab processing fee
Total T3 measures all of the triiodothyronine in your blood — the roughly 99% carried on binding proteins plus the small free fraction. T3 is the more active thyroid hormone, and in hyperthyroidism it often rises earlier and further than T4, so total T3 is part of the standard work-up when TSH is low: it distinguishes ordinary Graves' disease or toxic nodules from the less common 'T3 toxicosis' in which only T3 is elevated, and it helps gauge severity. It is less useful for diagnosing an underactive thyroid, where T3 tends to stay normal until late. Because total T3 counts protein-bound hormone, anything that changes binding proteins — pregnancy, estrogen, oral contraceptives, liver disease, some medications — shifts the result without changing thyroid function, which is why clinicians read it alongside TSH and free T4 (and sometimes free T3).
Thyroid testing measures the hormones that regulate metabolism, energy, body temperature, weight, and mood — identifying both overactive and underactive thyroid conditions.
Anyone with fatigue, weight changes, mood changes, hair loss, cold/heat intolerance, irregular cycles, or family history of thyroid disease.
Sample Type
Blood draw
Fasting
Not required
Results In
1–3 business days
Performed At
Quest or Labcorp
1 biomarker tested
Your T3, Total (Triiodothyronine) results will include values for each of the 1 biomarker 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. Already have results? Analyze them with your AI assistant against our physician-reviewed ranges.
No fasting required. Stop high-dose biotin supplements at least 2 days before the draw (biotin interferes with thyroid assays). If you take thyroid medication, take your dose after the blood draw.
What can throw off this result
Physician-reviewed “Before your test” pages — what each factor does, for how long, and what to do about it.
A Total T3 (Triiodothyronine) test costs $24.99 at TestWell — $30.99 all-in, since the $6 lab processing fee is charged once per order and there is no draw or physician fee. Hospital outpatient labs typically bill around $120.00 self-pay. With insurance you pay your plan's negotiated rate against your deductible; TestWell's price is fixed before the draw and HSA/FSA-eligible.
| Where you order | Price | One test, all-in | Notes |
|---|---|---|---|
| TestWell (drawn at Quest) | $24.99 | $30.99 | Includes the one $6 lab processing fee, charged once per order |
| TestWell (drawn at Labcorp) | $29.99 | $35.99 | Labcorp's own cost for this test is higher; same order, same portal, same physician review |
| TestWell (drawn at BioReference — New York & New Jersey) | $24.99 | $30.99 | New York and New Jersey orders route to BioReference; Quest Health and Labcorp OnDemand don't take self-ordered draws in those states |
| Hospital outpatient lab, self-pay (typical) | $120.00 | $120.00 | Reference figure; hospital charges vary widely by facility and are often higher |
Lab test codes: Quest test code 859 · Labcorp test no. 002188 · BioReference code 0150-3. Competitor prices are read from the linked public pages and re-checked regularly; the labs' sites may add taxes or change prices without notice.
Compare more: Quest Diagnostics price list · Labcorp price list · Quest vs Labcorp · Lab test price checker
Most T3, Total (Triiodothyronine) results are available in 1–3 business days after your specimen arrives at the lab. You'll get an email the moment results are ready, with everything viewable in your TestWell portal.
Blood draw. A standard venous blood draw, collected at any Quest, Labcorp or BioReference patient service center — walk in with the requisition we email you, no appointment needed at most locations.
On TestWell, the T3, Total (Triiodothyronine) is $24.99. Quest Direct lists comparable tests at $45. Walk-in hospital labs typically bill $120 or more without insurance. Insurance is not required — pay one all-in price.
No fasting required for the T3, Total (Triiodothyronine). No fasting required. Stop high-dose biotin supplements at least 2 days before the draw (biotin interferes with thyroid assays). If you take thyroid medication, take your dose after the blood draw.
The T3, Total (Triiodothyronine) is available at Quest and Labcorp patient service centers nationwide. Order online at TestWell, pick your preferred lab, and we'll generate a digital requisition for the location closest to you.
Biotin supplements, oral contraceptives and estrogen and ashwagandha and thyroid-support supplements can change a Total T3 (Triiodothyronine) test result without anything being wrong. Biotin supplements can falsely raise T3, Total — stop biotin ≥72 hours before the draw. Oral contraceptives and estrogen can raise T3, Total — use TSH and Free T4 — free levels are not affected. Ashwagandha and thyroid-support supplements can raise T3, Total — interpret with the supplement in mind; stop before a repeat draw only with the clinician's agreement. Each is explained on our physician-reviewed "Before your test" pages; when one applies, remove it and retest.
The Total T3 (Triiodothyronine) test is Quest Diagnostics test code 859, Labcorp test number 002188, BioReference code 0150-3. TestWell orders it under those codes for $24.99 at Quest, Labcorp or BioReference — no doctor's visit or insurance required, results in 1–3 business days. Codes verified against the labs' catalogs in 2026.
Medically reviewed by Youmna DiStefano, MD · Last reviewed September 2026
TestWell Price
$24.99
+ $6 lab processing fee at checkout
No insurance needed · HIPAA compliant
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