/ Thesaurus / R Synonyms of radioactive iodine test Find synonyms for: Noun1. radioactive iodine test, diagnostic test, diagnostic assayusage: test of thyroid function in which the patient is given an oral dose of radioactive iodine-131WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: immense Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language