Abstract. Four patients are described who had a significant elevation of serum thyroxine-binding globulin (TBG). Review of these patients indicated that inappropriate therapy for thyrotoxicosis had been given in three cases. Most of the protein-bound T3 and T4 in your body bind to thyroxine-binding globulin(TBG). The serum TBG level test measures the amount of TBG in your blood. This can help doctors assess thyroid. Thyroid-binding globulin (TBG) is produced in the liver and is a circulating protein that reversibly binds thyroid hormones3,5,3’-triiodothyronine (T3) and thyroxine (T4) and carries them in the bloodstream. The TBG blood test measures the level of a protein that moves thyroid hormone throughout your body. This protein is called thyroxine binding globulin (TBG). This protein is called thyroxine binding globulin (TBG). La globuline liant la thyroxine (TBG, de l'anglais : thyroxine-binding globulin) est l'une des trois classes de protéines transporteuses des hormones thyroïdiennes dans le sang, les deux autres étant la transthyrétine (TTR) et les albumines sériques. Abstract. It has been previously suggested that inherited thyroxine-binding globulin (TBG) abnormalities in man may be due to mutations at a single X-chromosome-linked locus controlling TBG synthesis. Thyroxine-binding globulin (TBG) is a globulin that binds thyroid hormones in circulation. It is one of three transport proteins (along with transthyretin and serum albumin) responsible for carrying the thyroid hormones thyroxine (T 4) and triiodothyronine (T 3) in the bloodstream. Uses of Thyroxine Binding Globulin Test The test results if used electrophoresis will range from 10 to 24/100ml of normal and if used radioimmunoassay, the normal results will range from 1.3 to 2.0 mg/100 ml. High TBG levels don’t always indicate that you have a problem and high results on this test are normal in pregnancy and in newborns. Inherited thyroxine-binding globulin deficiency is a genetic condition that typically does not cause any health problems. Thyroxine-binding globulin is a protein that carries hormones made or used by the thyroid gland, which is a butterfly-shaped tissue in the lower neck. Thyroxine-binding globulin (TBG) deficiency is a nonharmful condition that is either acquired or inherited. The only known complications associated with TBG deficiency are those stemming from the primary disorders that cause the acquired form of this condition. Complications could also potentially.