triiodothyronine 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