Total Thyroxine (Total T4)
Hormone markersWhat the test generally measures, and what to ask about it.
Longetic keeps every lab and record you’ve had organized and easy to find, so your own Total Thyroxine (Total T4) values sit together on one chart and you walk into your next appointment prepared.
What is Total Thyroxine (Total T4)?
Measures all of the thyroid hormone thyroxine in your blood, including both the free and protein-bound parts.
Thyroxine, or T4, is the main hormone the thyroid makes to control how your body uses energy, and the total T4 test captures both the free and bound forms. Higher levels can be associated with an overactive thyroid and lower levels with an underactive thyroid, though pregnancy, estrogen and other factors can shift the bound portion. It is usually interpreted together with TSH, and sometimes free T4, for a fuller picture.
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