Free T4 (FT4)
Free T4 is the metabolically active part of thyroxine. Free T4 and TSH can be used to determine the thyroid status. It is useful in patients who might be suffering from abnormal thyroid binding globulin during pregnancy. This occurs due to the treatment using estrogen, androgen, phenytoin or saclicylates. The test can also be useful in diagnosis of Hyper/hypo-thyroidism.
How to prepare for the test?
No special preparation is needed for this test.