The most common method for testing for iodine deficiency is to take urine samples, as the body releases iodine in the urine. Iodine deficiency is not tested in individuals; it is tested across populations using urine samples, according to the American Thyroid Association.
Iodine deficiency is relatively uncommon in developed countries such as the United States, as most brands of table salt include added iodine. However, deficiency is common in many developing countries in Asia, Africa, Latin America and parts of Europe, according to a December 2007 article in the Sultan Qaboos University Medical Journal. People get most of their iodine intake from foods; however, if the soil is deficient in iodine, the vegetables grown in that soil can also be deficient in iodine, leading to iodine deficiency across the local population. Iodine in soil tends to be low at high altitudes, but low levels can also result from flooding, intensive farming practices and the use of alkaline fertilizers.
Although iodine deficiency is rare in the United States and doctors do not issue individual tests for the condition, people who are concerned about their iodine levels can boost their levels by eating table salt that contains iodine and iodine-rich food such as dairy, seafood, meat and eggs. Some multivitamin supplements also contain iodine.
Symptoms of iodine deficiency include hypothyroidism and goiter.