OVERVIEW:
What is the free T4 lab test?
A free T4 lab test is a blood test that measures the level of free thyroxine (T4) circulating in the bloodstream.
Why is a free T4 lab test done?
A free T4 lab test is done in order to:
- Monitor thyroid gland function,
- Diagnose thyroid disorders,
- Diagnose congenital hypothyroidism in newborns,
- Monitor effectiveness of thyroid disorder treatment.
What does a free T4 lab test measure?
A free T4 lab test measures the level of free thyroxine (T4) circulating in the bloodstream. T4 along with T3 plays an important role in regulating the body metabolism.
Are there any risks associated with this test?
There are no known risks associated with this test.
How should I prepare for this test?
No special preparation is needed for this test.
Can this test be performed in children?
This test can be performed in children if necessary.
What are the causes behind a raised T4 level?
Hyperthyroidism, toxic nodular goiter, thyroiditis, and pregnancy can raise T4 levels.
What are the causes behind a low T4 level?
Hypothyroidism, hypopituitarism, malnutrition, or iodine deficiency decrease T4 level.
Normal range of free T4 in adults is 0.8 – 1.8 ng/dL.
A free T4 lab test is done in order to:
- Monitor thyroid gland function,
- Diagnose thyroid disorders,
- Diagnose congenital hypothyroidism in newborns,
- Monitor effectiveness of thyroid disorder treatment.