Thyroid Hormone Test - Thyroxine - T4

This test measures the blood level of a hormone made by the thyroid gland (Thyroxine, which is also known as T4).

This test measures the blood level of a hormone made by the thyroid gland (Thyroxine, which is also known as T4).

This test measures the blood level of T4 (Thyroxine), a hormone made by the thyroid gland. It is often done along with or after a thyroid-stimulating hormone (TSH) test and Triiodothyronine (T3) test.

  • Thyroid hormones help control how the body uses energy, and are also associated with managing body temperature, muscle function, heart rates and mental functioning.
  • This test may be done with other thyroid tests to see how well your thyroid gland is working.
  • It is also a common screening test in newborns.

In an adult, the blood sample is taken by placing a needle in a vein in the arm. In a newborn, the sample is taken by pricking the baby's heel.

  • Be sure to tell your healthcare provider about any medications you are taking. Some can interfere with the test.
  • This care path's costs do not include the charge to draw blood from a vein (venipuncture).
  • There will only be one charge to draw blood, even if multiple tests are being performed on the samples that are taken.

What should I ask my healthcare provider before having this test?

  • Is there any special preparation for the test? (If so, get clear instructions on what you need to do.)
  • What is the reason for the test? Will the test results change my treatment plan? If not, do I need the test?


Also known as:

Thyroid Hormone Test - Thyroxine - T4
Thyroid Gland
Thyroid Function
Thyroid Blood Test
T4 Blood Test
Laboratory Work
Hypothyroid Test
Hyperthyroid Test
Blood Test for Thyroid Disorder helps consumers determine the average cost of common medical procedures in their location. By gathering and analyzing data from leading insurance providers across the US, patients can compare the estimated price of common medical procedures to determine their approximate out-of-pocket expenses. All rates are approximations and not guarantees based on data that is available to the consumer. There are currently 638 procedures available in our database. These results and the information contained within should in no way take the place of actual medical advice.

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