I-131 Uptake Test

**Semantic type:** Diagnostic Procedure

**Definition:** A type of nuclear test of the thyroid that measures how much radioactive iodine is taken up by the thyroid gland in a given time period. This test is performed to evaluate thyroid function, particularly when blood tests of thyroid function (for example, T3 or T4 levels) have abnormal results. (from Medline Plus Medical Encyclopedia)

**Synonyms:** - I 131 Uptake - I-131 Uptake and Scan - Radioactive Iodine Uptake