--- title: Reverse T3 Test type: biomarker url: "https://www.test-well.com/biomarkers/reverse-t3" also_known_as: - reverse t3 - rt3 - reverse triiodothyronine category: Thyroid units: - ng/dL order_price_usd: 35.99 order_item: Reverse T3 order_url: "https://www.test-well.com/tests/reverse-t3" reviewed_at: 2026-09-05 --- # Reverse T3 > Reverse T3 is measured with a standard blood draw; no fasting is needed. A typical reference range is 8.00 – 25.0 ng/dL. At TestWell it's $35.99 all-in as Reverse T3, results in 4–7 business days, drawn at Quest or Labcorp. An out-of-range result is a prompt to look closer, not a diagnosis. Also known as: reverse t3, rt3, reverse triiodothyronine. ## Key facts | Fact | Value | | --- | --- | | Units | ng/dL | | Sample | Blood draw | | Fasting | Not required | | Results | 4–7 business days | | Price | $35.99 | | Labs | Quest or Labcorp · BioReference in NY/NJ | ## What does Reverse T3 measure? An inactive form of T3 that the body produces during stress, illness, or low-calorie states. ## What is the normal range for Reverse T3? | Population | Reference range | | --- | --- | | age 18+ | 8.00 – 25.0 ng/dL | Reference intervals differ slightly between labs; the range printed on your report is the one to interpret against. Ranges are usually set so 95% of healthy people fall inside them. ## What does a high Reverse T3 mean? Can reflect physiological stress, illness, severe dieting, or certain medications. ## How do you get tested for Reverse T3? | Order | Type | Price | Includes | | --- | --- | --- | --- | | [Reverse T3](https://www.test-well.com/tests/reverse-t3) | Single test | $35.99 | This marker | | [Complete Thyroid Panel](https://www.test-well.com/tests/thyroid-complete-panel) | Panel | $109.99 | 4 tests | | [Advanced Thyroid Panel](https://www.test-well.com/tests/advanced-thyroid-panel) | Panel | $129.99 | 7 tests | | [Female HRT Starting Panel](https://www.test-well.com/tests/female-hrt-starting-panel) | Panel | $249.99 | 20 tests | | [Men's Health Advanced Panel](https://www.test-well.com/tests/mens-health-advanced-panel) | Panel | $299.99 | 22 tests | ## Quest vs Labcorp vs BioReference | Lab | Available | Price | Notes | | --- | --- | --- | --- | | Quest Diagnostics | Yes | $35.99 | Choose Quest at checkout; walk-in patient service centers in every state TestWell serves outside NY and NJ. | | Labcorp | Yes | $35.99 | Choose Labcorp at checkout; walk-in patient service centers in every state TestWell serves outside NY and NJ. | | BioReference (NY & NJ) | Yes | $39.99 | New York and New Jersey orders route here automatically — state rules keep Quest and Labcorp from accepting self-ordered draws. | - [What a high Reverse T3 means (causes, symptoms, next steps)](https://www.test-well.com/biomarkers/reverse-t3/high) ## Common questions about Reverse T3 ### Do I need a doctor's order to test my reverse t3? No. TestWell's licensed physician network reviews and approves your order — usually within minutes. You can place an order online without an in-person visit or a referral from your own doctor. ### How long does it take to get Reverse T3 results? Most Reverse T3 results are available in 1–3 business days after your specimen arrives at the lab. You'll get an email the moment your results are ready, with everything viewable in your TestWell portal. ### How much does a Reverse T3 test cost? Our Reverse T3 starts at $35.99. That's the all-in price — no copays, no insurance hoops, no surprise bills. HSA and FSA cards are accepted. ### Do I need to fast before my Reverse T3 test? Fasting is not required for the Reverse T3 test. You can have your blood drawn any time of day. ### Which lab will process my Reverse T3 test? Your test will be processed by Quest Diagnostics, Labcorp, or BioReference depending on which is closest to you and which lab carries the test. All three are CLIA-certified and trusted by hospitals nationwide. You'll choose your lab during checkout from 4,000+ locations. ## Sources - [Mayo Clinic Labs](https://www.mayocliniclabs.com/test-catalog/overview/82051) - [American Thyroid Association — Thyroid function tests](https://www.thyroid.org/thyroid-function-tests/) ## Related biomarkers - [TSH](https://www.test-well.com/biomarkers/tsh) - [Free T4](https://www.test-well.com/biomarkers/free-t4) - [Free T3](https://www.test-well.com/biomarkers/free-t3) - [TPO Antibodies](https://www.test-well.com/biomarkers/tpo-antibodies) - [Thyroglobulin Antibodies](https://www.test-well.com/biomarkers/thyroglobulin-antibodies) - [Reference range lookup tool](https://www.test-well.com/tools/reference-range-lookup) - [Lab unit converter](https://www.test-well.com/tools/lab-unit-converter) - [All biomarkers](https://www.test-well.com/biomarkers) --- Medically reviewed by Youmna DiStefano, MD (Medical Reviewer, TestWell); last reviewed 2026-09-05. Review policy: https://www.test-well.com/reviewers/youmna-distefano-md Canonical page: https://www.test-well.com/biomarkers/reverse-t3 Machine-readable catalog: https://www.test-well.com/api/catalog.json · MCP server: https://www.test-well.com/mcp · Overview for agents: https://www.test-well.com/llms.txt Prices are cash-pay, in USD, and include physician authorization; every order adds one flat $6 lab processing fee. Educational content is not a diagnosis — discuss results with a clinician.