Biomarker Reference · Total T4
Total Thyroxine (Total T4) is a clinical biomarker used in thyroid-endocrine assessment. The aggregate of protein-bound and unbound fractions of circulating thyroxine. It is measured in 1 laboratory test on BiomarkersLabs.com.
The aggregate of protein-bound and unbound fractions of circulating thyroxine. Approximately 70% is bound to TBG, with the remainder bound to transthyretin and albumin. Total T4 reflects the full thyroxine pool but is not an accurate indicator of bioavailable thyroid hormone activity because the majority is protein-bound and inactive.
Primary utility in neonatal screening, pregnancy monitoring where protocol specifies total hormone measurement, and investigation of TBG-related binding abnormalities. In routine practice, Free T4 has replaced Total T4 because it is unaffected by binding protein changes.
Reference ranges vary by laboratory and assay platform. Interpret in context of the issuing laboratory's stated range.
1 test on BiomarkersLabs.com include this biomarker.
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