A Clinical Appraisal of Radioiodine Tests of Thyroid Function*

Radioiodine (I131) tests, like most other diagnostic laboratory procedures, are not fully effective in separating patients with thyroid disease from normal persons. Most radioiodine diagnostic tests thus far proposed can be used with relatively high precision in the separation of patients with exophthalmic goiter1 from normal individuals, but they are not nearly so efficient in the separation of persons with thyroid deficiency from normal persons, or in the detection of hyperthyroidism in patients who have adenomatous goiter. Thus, radioiodine tracers are more effective as diagnostic tests for certain thyroid states than for others.