This test measures Iodine levels in the blood. Iodine is an element which is essential for healthy functioning in many organs and systems such as the thyroid, heart, liver, lungs, and immune system. Proper iodine levels aid in the production of thyroid hormones. Too little or too much iodine can contribute to thyroid disorders such as hypothyroidism and hyperthyroidism. The measurement of iodine serves as an index of adequate dietary intake.