Accurate evaluation of thyroid function requires adjustment for hormone binding. The Free Thyroxine Index (FTI or T7) corrects total thyroxine measurements to estimate active hormone available for tissue uptake.
FTI is a calculated marker representing unbound, active thyroxine (Free T4) in circulation. It provides insight into thyroid status when plasma binding proteins vary.
FTI=Total T4×(T3 Uptake100)\text{FTI} = \text{Total T4} × \bigl(\tfrac{\text{T3 Uptake}}{100}\bigr)
Values outside these ranges may indicate thyroid dysfunction.
A decreased FTI suggests underactive thyroid hormone action, even when total T4 and TSH appear normal. This pattern supports diagnoses of primary hypothyroidism, which can present with fatigue, weight gain, depression, and cold intolerance.
An elevated FTI indicates excess active hormone and guides evaluation for hyperactive thyroid, often seen in conditions like Graves’ disease. Symptoms include weight loss, tremors, heat intolerance, and anxiety.
Beyond thyroid disorders, abnormal FTI may reflect altered binding protein levels in liver disease or nephrotic syndrome, or central hypothyroidism due to pituitary pathology.
In conclusion, a comprehensive evaluation by a functional medicine nurse practitioner in Florida facilitates identification of cellular-level and molecular imbalances underlying thyroid hormone availability. By integrating evidence-based allopathic therapies with longevity medicine medical care services—where hormonal optimization supports systemic resilience—we offer a preventive framework to rebuild health and vitality. Call (904) 799-2531 or schedule online to request your personalized thyroid assessment.
Ready to take the next step in optimizing your health? Contact us to schedule a comprehensive functional medicine evaluation centered on whole-person care. We offer convenient in-person and telemedicine appointments. Our team is available to assist with scheduling and to ensure you receive the support and care you need.
Comprehensive care with a whole person approach, specializing in injury management, wellness, and longevity.
hello@intercoastalhealth.com
4320 Deerwood Lake Parkway
Suite 327
Jacksonville, Florida 32216
Disclaimer: The content on this website is for informational purposes only and does not constitute medical advice or replace professional medical care, diagnosis, or treatment. Eligibility for medical treatments will be determined by your healthcare provider, who will exercise discretion regarding your treatment plan. All images are intended for educational purposes only. Statements made on this website have not been evaluated by the Food and Drug Administration. Always consult your healthcare provider before initiating or discontinuing any treatment.
Intercoastal Health – Copyright © 2025 All Rights Reserved.