Total T3
Total T3 measures both free and protein-bound triiodothyronine. Like total T4, it is affected by changes in binding proteins and is less preferred than free T3 for routine thyroid assessment. It can still be useful in diagnosing T3 toxicosis, a form of hyperthyroidism where free T3 rises disproportionately to T4.
3 providers include this
Thyroid Function
80-200 ng/dL
What is Total T3?
Total T3 measures both free and protein-bound triiodothyronine. Like total T4, it is affected by changes in binding proteins and is less preferred than free T3 for routine thyroid assessment. It can still be useful in diagnosing T3 toxicosis, a form of hyperthyroidism where free T3 rises disproportionately to T4.
Why It Matters
Active thyroid hormone. Measures both protein-bound and free T3. Affected by binding protein levels. Used with Free T3 for complete thyroid assessment.
Which Providers Test Total T3?
Full Provider Comparison
| Provider | Includes | Annual Cost | Biomarkers |
|---|---|---|---|
 Superpower | — | $199 | 100+ (150 with ratios) |
 WHOOP Advanced Labs | — | $349 | 65 |
 Labcorp OnDemand | — | $398 | 40+ |
| — | $486 | 40+ | |
| — | $449 | 288 | |
| — | $349 | 100+ | |
| — | $829 | 54 | |
 Function Health | — | $365 | 160+ |
| — | $250 | 65 | |
| — | $495 | 80+ | |
| ✓ | $895 | 100+ | |
| ✓ | $1950 | 130+ | |
| — | $375 | 95+ | |
| — | $Varies | 75+ | |
| — | $190 | 100+ | |
| — | $99 | 50 | |
| — | $124 | 60 | |
| — | $349 | 130+ | |
| — | $349 | 80+ | |
| — | $375 | 85 | |
| ✓ | $700 | 128 | |
| — | $99 | 100+ |
Frequently Asked Questions
What is Total T3?
Total T3 measures both free and protein-bound triiodothyronine. Like total T4, it is affected by changes in binding proteins and is less preferred than free T3 for routine thyroid assessment. It can still be useful in diagnosing T3 toxicosis, a form of hyperthyroidism where free T3 rises disproportionately to T4.
What is the optimal range for Total T3?
The standard reference range for Total T3 is 80-200 ng/dL. Optimal ranges may differ based on individual health goals and expert recommendations.
Which blood test providers include Total T3?
3 out of 22 blood testing providers include Total T3 in their panels. This biomarker has limited availability.
What category does Total T3 fall under?
Total T3 is categorized under Thyroid Function. This category includes biomarkers that help assess related aspects of health and wellness.
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Medical Disclaimer
This information is for educational purposes only and is not medical advice. Always consult with a qualified healthcare provider about your specific health needs.
Last reviewed:2026-04-12