FT4
Also known as: Free T4; T4
Formal name: Thyroxine
At a Glance
Why Get Tested?
To diagnose hypothyroidism or hyperthyroidism in adults
When to Get Tested?
FT4 may be is measured in response to an abnormal TSH test result
Sample Required?
A blood sample drawn from a vein in the arm.
Test Preparation Needed?
None but tell your doctor what medications you are taking as some may affect the test results.
