T4, Free Most Popular

The T4, Free test contains 1 test with 1 biomarker.

The free T4 are tests thelps evaluate thyroid function. The free T4 test is used to help diagnose hyperthyroidism and hypothyroidism. Free T4 is the active form of thyroxine and is usually ordered along with or following a TSH test. This helps the doctor to determine whether the thyroid hormone feedback system is functioning as it should, and the results of the tests help to distinguish between different causes of hyperthyroidism and hypothyroidism.

The following is a list of what is included in the item above. Click the test(s) below to view what biomarkers are measured along with an explanation of what the biomarker is measuring.

Also known as: Free T4, FT4, T4 Free

T4, Free

The free T4 test is not affected by protein levels. Since free T4 is the active form of thyroxine, the free T4 test is may be a more accurate reflection of thyroid hormone function.
*Process times are an estimate and are not guaranteed. The lab may need additional time due to weather, holidays, confirmation/repeat testing, or equipment maintenance.