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FTI details
Description
The Free Thyroxine Index (FTI) is a calculated value, derived from total T4 and a related binding-capacity test (T3 uptake), designed to estimate your free (unbound, active) T4 level without measuring it directly. It was more commonly used before direct free T4 assays became widely available and reliable; today, most labs simply measure free T4 directly, making FTI a somewhat older approach still occasionally used or reported in certain settings, serving the same basic purpose as a direct free T4 result.
- These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.