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Medical Term:

free thyroxine index


Definition: an arbitrary value obtained by multiplying the triiodothyronine uptake by the serum thyroxine concentration; it largely corrects for variations in thyroid-bound globulin concentration by providing a clinically valid estimate of the physiologically active free thyroxine; direct assay or laboratory measurement of free serum thyroxine yields a more accurate value.

© Copyright 2016 Wolters Kluwer. All Rights Reserved. Review Date: Sep 19, 2016.