T3 uptake test

tri·i·o·do·thy·ro·nine up·take test

a test of thyroid function in which triiodothyronine (T3) is added to a patient's serum in vitro to measure the relative affinities of serum proteins and of an added competitive substance for T3; higher T3 uptakes are associated with hyperthyroidism. Synonym(s): T3 uptake test

T3 uptake test

Triiodothyronine uptake assay, T3 resin uptake A test that indirectly measures free T4 as a reflection of the amount of T3 that can be bound to carrier proteins, in particular to thyroxin-binding globulin. See Thyroxine, Triiodothyronine.