diagnostic procedure perchlorate discharge test In the perchlorate discharge test, first radioactive iodine is administered, sufficient time is allowed to pass so that the radioactive iodine is captured by the thyroid, and then, perchlorate is administered orally. The perchlorate displaces non-organified iodide from the thyroid. The perchlorate discharge test is considered positive (abnormal) if there is an abnormally rapid loss of radioactive iodine from the thyroid. 2023-04-11T12:00:00Z