Total T4
Measures total thyroid hormone T4 levels to assess thyroid function and metabolism.
What This Test Measures
Specimen & Collection
Preparation
No fasting is required for this test. Inform your healthcare provider of any thyroid medications, biotin supplements, or other medications you are taking, as these may affect results.
Biomarkers Included (2)
Click any biomarker for detailed information
T-uptake in T uptake units. T uptake units bear a rough INVERSE relationship to the other T uptake (See AxSym package insert: http://www.promtest.am/tests/thyroid-diagn/T-Uptake.pdf), but actually measures a different phenomenon (total binding capacity instead of unbound hormone).
The free T4 index is a calculated measure of thyroid hormone activity that estimates the amount of thyroxine (T4) available to affect your metabolism. Unlike total T4, it accounts for proteins that bind thyroid hormones, providing a more accurate picture of active thyroid hormone. This test helps evaluate thyroid function and diagnose hyperthyroidism or hypothyroidism when TSH alone may be unclear.
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This information is for educational purposes only and does not constitute medical advice, diagnosis, or treatment. Always consult with a qualified healthcare provider regarding any medical condition or treatment plan.
Lab results should be interpreted by a licensed healthcare provider in the context of your complete medical history. Processing times may vary by laboratory. Charges will not be submitted to insurance, Medicare, or Medicaid. Direct-access lab testing is not available in NY, NJ, or RI.