Free Thyroxine (Free T4) [Serum]*

. Anti-Thyroglobulin Antibodies (Anti-Tg) are antibodies directed against thyroglobulin, a protein produced by the thyroid gland.
. Anti-Tg is often associated with autoimmune thyroid diseases, particularly Hashimoto’s thyroiditis leading to hypothyroidism. Although anti-TPO antibodies are not the primary diagnostic marker for Graves’ disease (which is more commonly diagnosed with TSI), they can be elevated in some cases, especially in patients with a coexisting autoimmune thyroiditis or those with longstanding Graves’ disease. It may also be elevated in thyroid cancer, and used to monitor for recurrence after treatment.
. Anti-Tg can also be present in non-thyroid conditions e.g., other autoimmune diseases (Rheumatoid arthritis), pernicious anaemia and Type I Diabetes.

. TT4 is used to evaluate the function of the thyroid gland, which regulates metabolism, energy production, and overall growth and development.
. TT4 measures the total amount of T4 hormone in the blood, including both bound and free forms. levels can fluctuate with physiological and pathological changes in TBG concentration.
. TT4, along with other TFT, is used to diagnose thyroid dysfunction (e.g., hyperthyroidism, hypothyroidism), to monitor treatment for thyroid disorders (especially in those taking thyroid hormone replacement or anti-thyroid medications), to evaluate conditions such as Graves’ disease, Hashimoto’s thyroiditis, or thyroid nodules, and to detect non-thyroidal illness (conditions affecting thyroid hormone levels independently of thyroid function).

. FT3 is used to evaluate the function of the thyroid gland, which regulates metabolism, energy production, and overall growth and development.
. FT3 measures the unbound, active form of T3. The FT3 is the form that the body uses directly to regulate various physiological processes.
. FT3, along with other TFT, is used to diagnose thyroid dysfunction (e.g., hyperthyroidism, hypothyroidism), to monitor treatment for thyroid disorders (especially in those taking thyroid hormone replacement or anti-thyroid medications), to evaluate conditions such as Graves’ disease, Hashimoto’s thyroiditis, or thyroid nodules, and to detect non-thyroidal illness (conditions affecting thyroid hormone levels independently of thyroid function).

. Thyroglobulin is a protein produced by the thyroid gland.
. While thyroglobulin is not a standalone screening test for thyroid cancer, it can aid in identifying individuals with differentiated thyroid cancer (e.g., papillary or follicular thyroid cancer), when used alongside other tests and imaging e.g., ultrasound, CT scans, or radioactive iodine scans. It may also be elevated in non-cancerous conditions like thyroiditis or goiter, and in some cases, benign thyroid nodules.
. In cancers, this tumor marker is used as an aid in monitoring the recurrence/progression and in assessing the response to therapy.
Note: Thyroglobulin levels can vary between different manufacturers due to differences in assay methods and reagent specificity. Results obtained from different manufacturers cannot be used interchangeably.

. Anti-Thyroid Peroxidaes Antibodies (Anti-TPO) are antibodies directed against thyroid peroxidase (TPO), an enzyme involved in the production of thyroid hormones in the thyroid gland.
. Anti-TPO is often associated with autoimmune thyroid diseases, particularly Hashimoto’s thyroiditis leading to hypothyroidism. Although anti-TPO antibodies are not the primary diagnostic marker for Graves’ disease (which is more commonly diagnosed with TSI), they can be elevated in some cases, especially in patients with a coexisting autoimmune thyroiditis or those with longstanding Graves’ disease.
. Anti-TPO can also be present in non-thyroid conditions e.g., other autoimmune diseases (Rheumatoid arthritis), Addison’s disease and Type I Diabetes.