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Triiodothyronine, Free (Free T3) Blood Test from Mito Health

Labbrary Test GradeUseful
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Not calculated

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Labbrary's review, Fit Score, and basic comparison are free. The provider's panel, shipping, collection, clinician review, and other services are separate. About 2 minutes. No account required.

Measures unbound triiodothyronine to help evaluate thyroid function alongside TSH and free T4, particularly when hyperthyroidism is suspected. Order online for a participating laboratory blood draw.

Current price
$10.59 from $20.09 with fees
Sample
Blood
Turnaround
1 to 2 days
Access
Lab Visit, Order Online
Evidence & Key Facts
Source collectedLast source check September 9, 2026

Evidence basis. This named result reflects the sources and verification evidence listed on this page as of the date shown.

Best for

Thyroid

Standout strength

One free T3 result, distinct from total T3 and reverse T3.

Important watch-out

Free T3 adds limited information when hypothyroidism is suspected. Biotin and thyroid medication can affect interpretation; follow the selected laboratory and prescribing clinician instructions.

Triiodothyronine, Free (Free T3) Blood Test from Mito Health
Labbrary Test GradeUseful
Your Fit Score
Not calculated

Answer five questions to see how this panel matches your goals, budget, collection preferences, access, and support needs.

Calculate my fit

Labbrary's review, Fit Score, and basic comparison are free. The provider's panel, shipping, collection, clinician review, and other services are separate. About 2 minutes. No account required.

Measures unbound triiodothyronine to help evaluate thyroid function alongside TSH and free T4, particularly when hyperthyroidism is suspected. Order online for a participating laboratory blood draw.

Current price
$10.59 from $20.09 with fees
Sample
Blood
Turnaround
1 to 2 days
Access
Lab Visit, Order Online
Evidence & Key Facts
Source collectedLast source check September 9, 2026

Evidence basis. This named result reflects the sources and verification evidence listed on this page as of the date shown.

Best for

Thyroid

Standout strength

One free T3 result, distinct from total T3 and reverse T3.

Important watch-out

Free T3 adds limited information when hypothyroidism is suspected. Biotin and thyroid medication can affect interpretation; follow the selected laboratory and prescribing clinician instructions.

Labbrary+

The Test Grade. The Reason Behind It.

Potentially useful for the right buyer, with meaningful evidence, coverage, transparency, access, cost, terms, or privacy tradeoffs to review.

A lower grade does not mean a panel is a bad personal fit. Your Fit Score can be higher when its purpose, price, sample, access, or support matches what you need.

Explore the Full Methodology
Labbrary Test GradeUseful

Next step

Check the panel or research the provider

Prices, availability, and ordering requirements can change. Confirm the current details before purchasing.

View Exact Panel on Provider SiteView Mito Health profile

Scope, both directions

Inside the Panel. Beyond the Name.

Named measurements

  • Free T3

Measured categories and focus areas

  • Thyroid

Important limits and omissions

  • Exact order or draw fees and order-specific refund terms remain unconfirmed.
  • Exact analytical method, performing laboratory and offer-specific validation remain unconfirmed.
  • Exact specimen retention and sharing terms remain unconfirmed under the provider privacy policy.

No broader panel in the Labbrary catalog lists every biomarker on this one for a lower listed price.

Counted among one-time lab-draw listings with a published price, matched by published biomarker names. That doesn’t mean the tests are equivalent. Updated October 2, 2026.

The full breakdown

Eight Dimensions.
One Named Result.

Open any row for the reasoning and evidence behind the named result.

Measurement quality is partial: exact offer names laboratory system(s) Labcorp; Quest Diagnostics and states collection at a CLIA/CAP-accredited lab. Seller Mito Health, collection route, and ordering clinician are separated above. A laboratory system name does not identify the exact performing facility, the assay method, or offer-specific analytical performance. Limitation: Measurement quality is partial: exact offer names laboratory system(s) Labcorp; Quest Diagnostics and states collection at a CLIA/CAP-accredited lab. Seller Mito Health, collection route, and ordering clinician are separated above. A laboratory system name does not identify the exact performing facility, the assay method, or offer-specific analytical performance. No score or grade assigned.

A low TSH or symptoms of overactive thyroid: racing heart, weight loss, tremor, heat intolerance, anxiety Free T4 came back normal but hyperthyroidism is still suspected Monitoring for relapse after treatment for Graves disease or a thyroid nodule A binding-protein abnormality (pregnancy, estrogen therapy) is clouding other thyroid results. Limitation: No additional limitation was recorded in the authority row.

Measures: Mass concentration What you'll learn Insights that connect the dots. Limitation: Complete named list not re-verified against the current page in this pass.

Reviewed by a real clinician. Results arrive in your dashboard. Limitation: No additional limitation was recorded in the authority row.

$7.56 Member price | $10.59 Non-member. Limitation: Draw/order fees and order-specific exceptions may apply; confirm before payment.

Find labs near you; lab-drawn collection. Limitation: Local booking availability requires confirmation.

Cash price $10.59 non-member / $7.56 member. HSA/FSA eligible. Limitation: Exact-offer refund terms not stated on the product page; shared Terms of Service govern refunds and credits.

Mito Health Privacy Policy governs data handling: https://mitohealth.com/privacy. Limitation: Exact-offer data retention and sharing terms not stated on the product page.

What it asks of you

Sample and fulfillment journey

Order

Confirmed

Select your state, laboratory and Triiodothyronine, Free (Free T3) Blood Test online. Mito supplies the laboratory order when required.

Panel-specific source · Source dated September 9, 2026

Collect

Confirmed

Blood collection at a participating laboratory selected for your state. Available laboratories: Labcorp, Quest Diagnostics, BioReference. No fasting is required. Ask the selected laboratory and clinician about biotin preparation. Note thyroid medication dose and timing when discussing results.

Panel-specific source · Source dated September 9, 2026

Report

Confirmed

Results appear in the Mito dashboard after laboratory processing and receive clinician review. Personalized action plans require membership; live consultations cost extra.

Panel-specific source · Source dated September 9, 2026

Under the hood

Follow the Evidence.

Every published claim should trace to a dated source. Missing evidence remains visible instead of being filled with assumptions.

Source 1Recorded for this record. Last source check September 9, 2026.View source

True total cost

The Price. Plus the Details.

Pricing for Triiodothyronine, Free (Free T3) Blood Test
ItemCurrent disclosed priceNote
Panel$10.59Verify the checkout total, shipping, and collection fees before ordering.
Lab draw fee+ $9.50 to $15Per lab visit, added at checkout. One applies, depending on the lab you use: BioReference $9.50, Labcorp $11.50, Quest $15. Checked September 29, 2026. Source
Total at checkoutFrom $20.09Listed price plus the required fees above, before tax and any optional services.
HSA/FSA paymentNot confirmedHSA/FSA payment eligibility has not been confirmed from provider documentation.
Optional servicesAt-home phlebotomist, $99Only if you choose it. Not included in the total. Checked September 29, 2026. Source

Price status. This record shows disclosed pricing. Checkout costs can change and should be verified before purchase.

Your data

Your Data. Your Questions.

Privacy details are scored only when source documentation is available. Unconfirmed retention, deletion, research use, or marketing practices remain unconfirmed.

Reading the labels

What Has Been Checked?

Source collected

Evidence labels stay separate from the Test Grade. They show how much source support exists for the evaluation.

The balance

The Strengths. The Tradeoffs.

Strengths

  • One free T3 result, distinct from total T3 and reverse T3.
  • Online ordering with collection at a participating laboratory.
  • Typical results in 1-2 days, as a provider estimate; timing can vary.

Watch-outs

  • Free T3 adds limited information when hypothyroidism is suspected. Biotin and thyroid medication can affect interpretation; follow the selected laboratory and prescribing clinician instructions.
  • Member prices require membership. Displayed test prices depend on the selected laboratory and state; applicable order or draw fees can increase the final total.
  • Results appear in the Mito dashboard after laboratory processing and receive clinician review. Personalized action plans require membership; live consultations cost extra.
  • Actual report presentation and complete order-specific cost remain unverified.

Take it with you

The Test Truth Card

The key facts from this review in one compact card.

Same biomarkers, other sellers

Other Ways to Buy This Test.

2 other listings in the Labbrary catalog publish this exact biomarker list, with a lab draw.

Free Triiodothyronine (FT3) (Free T3)

Marek Health

Useful

Measure free T3, the active thyroid hormone available to your tissues, to add information to a thyroid-function assessment.

Price
$20
Turnaround
14 days
See Labbrary reviewView Exact Panel on Provider Site
Labbrary+

Free T3

Everlywell

Useful

Measures Free T3 using a blood sample collected at a participating location. Order online, complete clinician review and access results through your account.

Price
$43
Turnaround
Not confirmed
See Labbrary reviewView Exact Panel on Provider Site
Labbrary+

Listed prices from the Labbrary catalog. Some sellers add fees at checkout, so compare the total before you pay. Updated October 2, 2026.

Keep deciding

Free Thyroxine (FT4) (Free T4)

Marek Health

Useful

Measure free T4, the unbound thyroid hormone available to your tissues, as part of an assessment of thyroid function.

Price
$13
Turnaround
14 days
See Labbrary reviewView Exact Panel on Provider Site
Labbrary+

Triiodothyronine (T3), Total Blood Test

Mito Health

Useful

Measures total T3 for clinician-guided investigation of an overactive thyroid, including cases with normal T4. Order online for a partner-lab blood draw; no fasting is required.

Price
$8.07
Turnaround
1 day
See Labbrary reviewView Exact Panel on Provider Site
Labbrary+

Comprehensive Wellness Panel

Request A Test

Useful

Request A Test Comprehensive Wellness Panel combines CBC, CMP, HbA1c, lipid testing, urinalysis, vitamin D, and a thyroid basic panel with blood and urine specimens, estimated results in 1 to 3 business days, and location-based laboratory options.

Price
$195
Turnaround
3 days
See Labbrary reviewView Exact Panel on Provider Site
Labbrary+
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Verification History

September 9, 2026Recorded source date.Source collected

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