Thyroid
Reverse T3
LOINC 30932-8 · ng/dL
Ranges
Reference range: 9.2–24.1 ng/dL
What it is
Reverse T3 is an inactive form of thyroid hormone the body makes when converting T4. It is often higher during illness or stress.
Why it matters
It can add context to thyroid results, particularly when the body is unwell, though it is not a routine test.
What high values can mean
A higher value can occur during serious illness, fasting or stress, when the body shifts toward the inactive hormone.
What low values can mean
A lower value is generally not a concern on its own.
How to improve it
Reverse T3 usually reflects an underlying state; addressing illness or stress is what changes it.
Food & lifestyle
No specific food targets reverse T3; overall recovery and good nutrition support normal thyroid metabolism.
Preparing for the test
A blood test; fasting is not required — follow your lab's instructions.
When to talk to a doctor
Reverse T3 is interpreted by a clinician with the full thyroid picture, not on its own.
Related markers
Sources
- Testing.com (AACC)
- NIH (NCBI)
Content reviewed on June 26, 2026
Medical disclaimer
This content is for educational purposes only. It is not medical advice and does not diagnose, treat, or prevent any condition. Reference ranges vary between laboratories — always use the range printed on your report and discuss your results with a healthcare professional.
See your own values in context
Bllod turns your lab report PDFs into clear, tracked results — every marker organized, explained, and charted over time.