Complete Thyroid Diagnostics: Free T3, Reverse T3 & Hashimoto's Antibodies
Reviewed by Integrative Medicine & Clinical Nutrition Faculty Board
Clinical Overview
Why TSH alone misses 80% of thyroid dysfunction: evaluating peripheral T4-to-T3 conversion, Reverse T3 pooling, and anti-TPO/anti-Tg autoimmune flares.
A complete functional thyroid panel evaluates the active intracellular hormone Free T3 rather than relying solely on pituitary feedback via Thyroid Stimulating Hormone (TSH).
1. Functional Thyroid Panel Targets
Biomarker
Standard Lab Range
Optimal Functional Target
Clinical Role
TSH
0.45 – 4.50 μIU/mL
1.0 – 2.0 μIU/mL
Pituitary feedback signal
Free T4
0.8 – 1.8 ng/dL
1.2 – 1.5 ng/dL
Storage pro-hormone pool
Free T3
2.0 – 4.4 pg/mL
3.4 – 4.2 pg/mL
Active metabolic hormone
Reverse T3 (rT3)
9.2 – 24.1 ng/dL
< 15.0 ng/dL
Inactive competitive inhibitor
Free T3 / rT3 Ratio
> 10
> 20 (Optimal)
Peripheral conversion efficiency
TPO / Tg Antibodies
< 34 IU/mL
< 2 IU/mL (Negative)
Hashimoto's thyroiditis autoimmune flare
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Integrative Medicine & Clinical Nutrition Faculty Board
Our clinical faculty specializes in functional endocrinology, GI-MAP microbiome restoration, advanced lipidology (ApoB/Lp(a)), and cellular longevity medicine.
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