Monday, May 11, 2009

Iodine perchlorate discharge test

The iodine perchlorate discharge test is used in the diagnosis of impaired organification within the thyroid. Potassium or sodium perchlorate is a competitive inhibitor of iodide trapping, resulting in release of untrapped iodide from the thyroid. When organification is normal, perchlorate does not cause a significant change in the iodide content of the thyroid, since most iodide is organified and cannot be released. When organification is impaired, perchlorate causes a decrease in thyroid iodide content.

The test is performed by quantifying thyroid uptake two hours after administration of radiolabeled iodine. One hour after administration of potassium perchlorate, thyroid uptake is again quantified. In normal subjects, the uptake values remain relatively unchanged. In patients with impaired organification, there is a decrease of greater than 5% following perchlorate administration.

References

Sarkar SD and Becker DV. Thyroid uptake and imaging (Chapter 34). in Principles and Practice of Endocrinology and Metabolism, Third Edition. Becker KL et al (eds). Lippincott Williams & Wilkins (2002).

No comments:

Post a Comment

Note: Only a member of this blog may post a comment.