Reverse T3 levels: what's normal, high and low
An inactive form of T3 that the body produces during stress, illness, or low-calorie states.
Medically reviewed by Youmna DiStefano, MD · Last reviewed September 2026
The short answer
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.
- 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
Reverse T3 Reference Range
These are the typical adult reference ranges used by major US labs. Your report will include the specific range used by the lab that processed your sample.
| Population | Range |
|---|---|
| age 18+ | 8.00 – 25.0 ng/dL |
Reference ranges are educational. Always interpret your result with the specific range printed on your lab report and discuss anything outside the range with a clinician.
What your Reverse T3 result may mean
Can reflect physiological stress, illness, severe dieting, or certain medications.
What a high Reverse T3 means: causes, symptoms, next steps →Educational only — not a diagnosis. Many factors can influence a single result. Discuss anything that concerns you with a healthcare provider.
How do you get a Reverse T3 test?
Order online, a licensed physician reviews the requisition, and you walk into a nearby lab for the draw. Reverse T3 is available on its own or inside these panels — panels cost less per marker when you want the fuller picture.
| Option | Includes | Price |
|---|---|---|
| Reverse T3 | This marker only | $35.99 |
| Complete Thyroid Panel | 4 tests | $109.99 |
| Advanced Thyroid Panel | 7 tests | $129.99 |
| Female HRT Starting Panel | 20 tests | $249.99 |
| Men's Health Advanced Panel | 22 tests | $299.99 |
Quest vs. Labcorp for Reverse T3: which lab should you pick?
Both are CLIA-certified national labs and the result is clinically equivalent, so pick whichever location is closer. Your report will print that lab's own reference range, which can differ slightly from the table above.
| Lab | Available | Price |
|---|---|---|
| Quest Diagnostics | Yes | $35.99 |
| Labcorp | Yes | $35.99 |
| BioReference (NY & NJ) | Yes | $39.99 |
Need help choosing a location? Use the lab finder to see draw sites near your ZIP.
Related Thyroid biomarkers
Markers commonly tested alongside Reverse T3.
Frequently asked
Can reflect physiological stress, illness, severe dieting, or certain medications. A single result above the reference range is a prompt to look closer with a clinician — often a repeat test and related markers — not a diagnosis on its own.
Ready to test your reverse t3?
Order in two minutes, get physician-approved, and visit a lab the same day. Starts at $35.99.