Category: Thyroid Diseases

Additional Information Reverse triiodothyronine (rT3) is an isomer of triiodothyronine (T3) with no demonstrated biological activity.1,2 The majority of rT3is produced through peripheral enzymatic monodeiodination of T4 at the 5 position of the inner ring of the iodothyronine nucleus of thyroxine (T4)

Test Details Synonyms Third-generation TSH Thyrotropin Use Thyroid function test. Investigation of low thyroxine (T4) result; the differential diagnosis of primary hypothyroidism from normal, and the differential diagnosis of primary hypothyroidism from pituitary/hypothalamic hypothyroidism

Test Details Synonyms Free T3 T3, Free Use Evaluate thyroid function and assess abnormal binding protein disorders.

Test Details Synonyms T3, Total Use Thyroid function which is particularly useful in the diagnosis of T3 thyrotoxicosis, in which T3 is increased and T4 is within normal limits. T3 toxicosis is occasionally found in Graves’ disease. It occurs with a single toxic nodule, multinodular thyrotoxicosis,

Test Details Synonyms Free T4, Direct, Serum Free Thyroxine T4, Free, Direct, Serum Use Free T4 may be indicated when binding globulin (TBG) problems are perceived, or when conventional test results seem inconsistent with clinical observations. It is normal in subjects with high thyroxine-binding

Test Details Synonyms T4, Total Tetraiodothyronine Use Thyroid function test. Decreased in hypothyroidism and in the third stage of (painful) subacute thyroiditis; increased with hyperthyroidism, with subacute thyroiditis in its first stage and with thyrotoxicosis due to Hashimoto disease.3

Test Details Synonyms Free Testosterone, Direct and Total. Use Evaluate hirsutism and masculinization in women; evaluate testicular function in clinical states where the testosterone binding proteins may be altered (obesity, cirrhosis, thyroid disorders). See individual test descriptions for

Test Details Synonyms Free Testosterone, Direct Use Evaluate hirsutism and masculinization in women; evaluate testicular function in clinical states where the testosterone binding proteins may be altered (obesity, cirrhosis, thyroid disorders).

Test Details Synonyms Thyroid Hormone-binding Ratio (THBR). Use Thyroid function test for the diagnosis of hypothyroidism or hyperthyroidism, used with thyroxine (T4) or equivalent to provide free T4 index, FTI. An indirect measure of binding protein, the T3 uptake reflects available binding