Need a check-up? Essential health screening $89. (CMP, CBC, UA & Lipid Profile)
Comprehensive Panels are the best value
Browse Categories

Monthly Newsletter
     • Health News
     • Featured Tests

Free T3

Our Price:
T3 is one of the hormones made by the thyroid, the butterfly-shaped gland found in front of the windpipe. T3 and free T3 are essentially the same, except that free T3 more greatly affects how the body uses energy. The main difference is that free T3 is not bound, or attached to, thyroxine-binding globulin. Only free T3 is truly usable by the body.

T3 is needed for normal brain development, especially during the first three years of life. This hormone helps children grow and develop normally. In adults the hormone regulates metabolism: how the body uses energy. According to the United States Preventive Services Task Force, all newborns should be tested for congenital hypothyroidism.

Most of the T3 in the blood is bound to thyroxine-binding globulin. Less than one percent of the T3 is free. The free T3 blood test is used to help determine what may be causing an abnormal thyroid-stimulating hormone (TSH) test. Measurements of free T3 levels are not affected by certain protein levels, so they remain more constant. Measuring free T3 gives a more accurate picture of the true concentration of T3 levels in the blood.

The test is also ordered for people who have been diagnosed with a thyroid diseases or disorder to check the efficacy of the thyroid treatment and determine if dosages should be changed. The free T3 test can be a screen for newborns to see if their thyroid gland functions are normal. Catching congenital hypothyroidism early can prevent abnormal growth and development and intellectual disability.