T4 (Total)
Measured T4 reflects hormone both bound to TBG and free. Normal range 5 - 11.5 mg/dL
Changes in either FT4 level (_ hypo, _hyperthyroidism) or the conc. of TBG alter total T4, but will not affect the free hormone level( patient asymptomatic). Increase synthesis of TBG (e.g., due to estrogen therapy or pregnancy) _ total T4. Reduction in