What is Thyroxine-Binding Globulin?
Thyroxine-binding globulin (TGB) is a protein that aids in thyroid function. The protein transports hormones produced in the thyroid to all parts of the body. TGB levels will increase during a pregnancy, so elevated numbers may be an indication of pregnancy. Other factors that cause a rise in TGB include liver disease and hypothyroidism.
If levels of TGB are lower than normal, the patient may be experiencing malnutrition, hyperthyroidism or severe illness. Further testing will be needed before a definitive diagnosis can be made.
Normal Value Range
- Negative Pregnancy Adult: 16 to 24 mg/dL or 16 to 24 µg/mL or 206 to 309 nmol/L
- Pregnancy Trimester One: 10 to 40 mg/dL or 10 to 40 µg/mL or 171 to 684 nmol/L
- Pregnancy Trimester Two: 23 to 46 mg/dL or 23 to 46 µg/mL or 393 to 786 nmol/L
- Pregnancy Trimester Three: 19 to 49n mg/dL or 19 to 49 µg/mL or 325 to 838 nmol/L