In people with hypothyroidism, TSH and free T4 are regularly checked to assure that the right dose of thyroid hormone is being given to make TSH normal. Back to top Is there anything else I should know?
Its concentration is measured by means of analysis of a blood sample drawn from the vein in the arm. Purpose of the test Thyroxine (T4) test is measured in order to check the levels of this hormone in blood in order to help diagnose thyroid disorders such as hyperthyroidism and hypothyroidism.
Gcid003517 ptid1 Thyroid Function Tests. (n.d.). American Thyroid Association. Retrieved June 1, 2012, from yroid. org/patients/brochures/FunctionTests_brochure. pdf Thyroxine (T4) Test. (n.d.). Summit Medical Group. Retrieved June 1, 2012, from m/library/adult_health/thyroxine_test/ Was this article helpful?
Anxiety Weight loss Difficulty sleeping Tremors in the hands Weakness Diarrhea (sometimes) Light sensitivity, visual disturbances The eyes may be affected: puffiness around the eyes, dryness, irritation, and, in some cases, bulging of the eyes.
A free T4 test may be used along with or following a. TSH test and sometimes with a free T3 test to: Help detect too much or too little thyroid hormone (hyperthyroidism and hypothyroidism) and diagnose the cause Distinguish between different thyroid disorders Help diagnose pituitary disorders Aid in the diagnosis of female infertility.
Most of the T4 and T3 circulates in the blood bound to protein, while a small percentage is free (not bound). Blood tests can measure total T4, free T4, total T3, or free T3.
An abnormal result on this test alone may not give your doctor enough information to fully understand or diagnose your condition. Pregnancy can affect your T4 levels. If your T4 levels are abnormal but you are pregnant, your doctor may order further testing.
What Is a T4 Test? Your thyroid produces a hormone, thyroxine, which is known as T4. This hormone plays a role in several of your bodys functions, including growth and metabolism.
In the United States, newborns are commonly screened for T4 levels as well as TSH concentrations to check for congenital hypothyroidism, which can cause mental retardation if left untreated. Free T4 along with TSH may sometimes be used to screen for thyroid disorders, but expert opinions vary on who can benefit from screening and at.
The total T4 test has been used for many years, but it can be affected by the amount of protein available in the blood to bind to the hormone. Free T4 is not affected by protein levels and is the active form of thyroxine.
If after a TSH test result low and a T4 test result normal or high, a T3 test result is normal or high, it can indicate hyperthyroidism. If after a TSH test result low and a T4 test result normal or low, a T3 test result is normal or low, it can indicate a nonthyroidal.