Iodine deficiency 15–20 mg of iodine in the human body which is primarily concentrated in thyroid tissue and hormones, but 30% of iodine is distributed in other tissues, including mammary glands, eyes, gastric mucosa, choroid plexus, arterial walls, the cervix, and salivary glands. In the cells of these tissues, iodide enters directly by sodium-iodide symporter (NIS). The diagnostic workup of a suspected iodine deficiency includes signs and symptoms as well as possible risk factors mentioned above. A 24-hour urine iodine collection is a useful medical test, as approximately 90% of ingested iodine is excreted in the urine. For the standardized 24-hour test,
Lugol's iodine 126.5 mg/mL. The 15% solution thus has a total iodine content of 6.32 mg per drop of 0.05 mL; the 2% solution has 0.84 mg total iodine content per drop. Potassium iodide renders the elementary iodine soluble in water through the formation of the triiodide () ion. It is not to be confused with tincture of iodine solutions, which consist of elemental iodine, and iodide salts dissolved in water and alcohol. Lugol's solution contains no alcohol. Other names for Lugol's solution are (iodine-potassium iodide); Markodine, Strong solution (Systemic); and Aqueous Iodine Solution BP. In the United Kingdom the NHS pays