radioiodine uptake test, one of the most common thyroid function tests. A known quantity of radioiodine is administered, and 6 and 24 hours later the percent that has been absorbed by the thyroid gland is calculated. An increased uptake indicates hyperthyroidism, and a decreased uptake indicates hypothyroidism. Patients who have recently been exposed to iodine compounds, such as in dietary supplements, contrast media, medications, or antiseptics, may not be good candidates for this test.
