Thyroxine-binding Globulin


For: ,

Quest Diagnostics Test Code: 870

Thyroxine-binding globulin is a type of binding protein that is produced in the liver with the function of binding to triiodothyronine (T3) and thyroxine (T4) hormones, that are made in the thyroid gland. These hormones are important in the regulation of body metabolism and energy expenditure rate. This test measures the blood levels of thyroxine-binding globulin in order to assess thyroid function. This test is usually performed after an abnormal T3, T4 or thyroid stimulating hormone (TSH) results.

This test is performed in following conditions such as:

Signs and symptoms of hyperthyroidism
• Weight loss
• Increased heart rate
• Anxiety
• Difficulty sleeping
Signs and symptoms of hypothyroidism
• Weight gain
• Dry skin
• Constipation
• Cold intolerance

Also Known As: TBG


This Thyroxine-Binding Globulin test has no fasting requirements.


Specimen Collected
  • Blood
Estimated Time Taken

Turnaround time for the Thyroxine-Binding Globulin test is typically 1-3 business days.