Immunoassays are one of the main methods of measuring thyroid hormones. They are prone to interference. Interference of the immunoassays has been increasingly recognized as a problem because it may lead to misinterpretation of results resulting in unnecessary investigation and wrong course of treatment. We describe a patient who had interference in her thyroid function measurements (free T4, free T3 and TSH) during the course of treatment for Graves' disease.
2008 by The Japanese Society of Internal Medicine