This test is used to distinguish between high T4 levels due to hyperthyroidism and due to increased binding by TBG in euthyroid individuals who have normal levels of free hormones.
It is a carrier protein synthsized in the liver. It binds to thyroid hormones T3 and T4 and helps their transport through blood. An increase in levels of TBG will result in increased levels of total T4 and T3, without actually increasing the activity of thyroid hormone. If the levels of T4 and T3 are not clinically explainable, TBG should be tested.
Suspected hyperthyroidism, monitoring treatment for hyperthyroidism.
No special preparation is necessary prior to blood sample collection.
Estimated Turn Around For Results:
2-10 Business Days
For an exact turnaround time for results, please contact us at Personalabs and we will contact the lab on your behalf as turnaround times vary depending on testing location or lab testing provider.