Email this page Print this article Was this page helpful?

T4

Also known as: Total T4; Free T4
Formal name: Thyroxine
Related tests: TSH; T3; Thyroid Antibodies

Common Questions

1.  How does pregnancy affect thyroid hormone levels?

Pregnancy can increase total T4 levels, although this does not mean that thyroid disease exists. For more information, see Thyroid Foundation of America: Thyroid Problems During and After Pregnancy - Are You At Risk?

^ Back to top

2.  What is FTI?

FTI stands for the Free Thyroxine Index and is also sometimes referred to as T7. It is a calculation using the results from the T3 uptake test and total T4 test and provides an estimate of the level of free T4 in the blood. It is rarely used anymore as we now have methods to measure free T4 and T3.

^ Back to top