Free Triiodothyronine (ft3), Serum

Triiodothyronine (T3) is one of the thyroid hormones produced by the thyroid gland, which plays a crucial role in regulating metabolism. Free T3 refers to the active form of T3 that is not bound to proteins in the blood, making it available to tissues and organs for use.

The FT3 test helps evaluate thyroid function and diagnose thyroid disorders:

• Hyperthyroidism: Elevated FT3 levels are commonly seen in conditions like Graves' disease or thyroiditis.
• Hypothyroidism: Low FT3 levels can indicate an underactive thyroid, which may be due to Hashimoto’s thyroiditis or iodine deficiency.
• Thyroid Dysfunction: In cases where total T3 levels might be affected by protein levels, FT3 gives a more accurate assessment of thyroid activity.

• Individuals with symptoms of thyroid disorders, such as weight changes, fatigue, hair thinning, or temperature sensitivity.
• People with a family history of thyroid disease.
• Patients who have abnormal results on other thyroid tests, such as TSH or T4.

Free T3 is typically measured along with other thyroid hormones, like Free T4 and TSH, for a comprehensive assessment of thyroid health. Elevated FT3 can indicate hyperthyroidism, while low FT3 can suggest hypothyroidism or other thyroid dysfunctions.