Understanding Lab Tests for Iodine-induced hyperthyroidism (IIH)
Written by Private MD Labs Medical Writing Team • Last Updated: September 8, 2025
Iodine-induced hyperthyroidism (IIH) is a form of hyperthyroidism caused by excessive iodine intake, which leads to overproduction of thyroid hormones. This condition can occur from consuming too much iodine through supplements, medications, or iodine-rich foods. Accurate diagnosis requires specific blood tests to measure both iodine levels and thyroid function.
Recommended Test
Iodine, Serum/Plasma
This test directly measures iodine levels in the blood, which is essential for diagnosing iodine-induced hyperthyroidism. Elevated iodine levels, particularly when accompanied by symptoms of hyperthyroidism, confirm that excessive iodine intake is the underlying cause of the thyroid hormone overproduction characteristic of IIH.
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Diagnosing Iodine-induced Hyperthyroidism
IIH differs from other forms of hyperthyroidism because it has a specific trigger - excess iodine. Blood tests are essential to confirm both the presence of hyperthyroidism and the elevated iodine levels that cause this condition. This distinction is crucial for proper treatment, which typically involves reducing iodine intake and managing thyroid hormone levels.
Understanding Your Results
High serum iodine levels combined with symptoms of hyperthyroidism (such as rapid heartbeat, weight loss, anxiety, or heat intolerance) strongly suggest iodine-induced hyperthyroidism. Your healthcare provider may also order additional thyroid function tests to assess the severity of thyroid hormone overproduction and monitor your response to treatment.
Important Considerations
The information here is for educational purposes only and is not a substitute for professional medical advice. Always consult with a healthcare provider for diagnosis and treatment. If you suspect iodine-induced hyperthyroidism, it's important to discuss your iodine intake sources with your doctor, including supplements, medications, and dietary habits.
