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T3

Also known as: Total T3; Free T3; FT3
Formal name: Triiodothyronine
Related tests: TSH; T4; Thyroid Antibodies

Common Questions

1.  How does pregnancy affect thyroid hormone levels?

Pregnancy can increase total T3 levels although it does not mean that thyroid disease will develop. For more information, see Thyroid Foundation of America: Thyroid Problems During and After Pregnancy - Are You At Risk?.

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2.  What is the T3 uptake test?

T3 uptake is also known as T3 Resin Uptake (T3RU) or Thyroid Uptake. It estimates how much thyroid hormone-binding proteins are available in the blood through a calculation based on levels of T3 or T4 added to a patientÂ’s blood specimen. It is rarely ordered anymore in favor of free T3 and free T4 levels.

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