Lab

Free Thyroxine Index

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Free Thyroxine Index, Free T4 Index, FTI, FT4I

  • See Also
  1. Thyroid Function Test
  2. Thyroid Function Summary
  3. Triiodothyronine ( Free T3)
  4. Thyroxine (Free T4)
  5. Thyroid Stimulating Hormone (TSH)
  6. Thyroxine Binding Globulin (TBG)
  7. Thyroid Releasing Hormone (TRH)
  8. Antithyroid Antibody
  9. Thyroxine Replacement
  10. Hypothyroidism
  11. Hyperthyroidism
  12. Hypothyroidism in Pregnancy
  13. Thyroid Dysfunction in Pregnancy
  • Interpretation
  • Normal
  1. Free Thyroxine Index: 4-11
  • Indications
  1. Largely replaced by Free T4 (Free Thyroxine)
  2. Corrects for abnormal Thyroid Binding Globulin (TBG)
  3. Free T4 also corrects for Thyroid Binding Globulin
    1. Free T4 is preferred over FTI
  • Measurement
  1. Calculated: T4 x T3 Binding Ratio (T3RU)