Radioactive iodine uptake

Injury	Disease	Nutrition	Poison

Symptoms	Surgery	Test	Special Topic

Radioactivity test

Overview

Risks

Results

Radioactive iodine uptake

Alternative Names:

Iodine uptake test; RAIU

What the risks are:

The risk is minimal. The amount of radioactivity is very small and there have been no documented side effects. However, as with any radiation exposure, this test is not recommended for women who are pregnant or breastfeeding.

The amount of iodine used is less than a normal dietary iodine intake. A history of iodine (contrast dye) allergy does not necessarily contraindicate testing, although history of allergy to dietary iodine (or shellfish) may contraindicate this test.

Special considerations:

The radioactive iodine is excreted in the urine. However, the amount of radioactivity is minute, so special precautions may or may not be advised for 24 to 48 hours (often this simply includes flushing twice after urinating). Consult the health care provider or the radiology/nuclear medicine department performing the scan.

Interfering factors:

iodine-deficient diet
iodine-excessive diet
recent (within the past two weeks) radiologic procedures using iodine-based contrast
diarrhea (may decrease absorption of the radioactive iodine)

Drugs that increase results include barbiturates, estrogen, lithium, phenothiazines, and thyroid stimulating hormone.

Drugs that decrease results include ACTH, antihistamines, corticosteroids, Lugol's solution, nitrates, SSKI (saturated solution of potassium iodide), thyroid drugs, anti-thyroid drugs, tolbutamide.

Review Date: 1/18/2006
Reviewed By: Nikheel S. Kolatkar, MD, Clinical and Research Fellow, Division of Endocrinology, Diabetes, and Hypertension, Brigham and Women's Hospital, Harvard Medical School, Boston, MA. Review provided by VeriMed Healthcare Network.

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