Iodine is an essential trace element required for the synthesis of thyroid hormones, which regulate metabolism, growth, and development. This test measures iodine levels in the blood to evaluate iodine status and diagnose deficiency or excess. Iodine deficiency can cause goiter, hypothyroidism, and in severe cases, cretinism in children. During pregnancy, iodine deficiency can lead to miscarriage, stillbirth, and congenital anomalies. Excessive iodine intake can cause iodine-induced hyperthyroidism or hypothyroidism, particularly in individuals with underlying thyroid disease. This test is essential for monitoring iodine supplementation programs, evaluating thyroid disorders, and assessing exposure in occupational settings. Regular monitoring helps prevent iodine deficiency disorders and ensures optimal thyroid function.