Misdiagnosis of Graves Disease

Posted by Elaine Moore Mar 7, 2006

Based on this study which was founded on the principles established in earlier studies that were conducted by Yamamoto, Brokken, Wiersinga, Terry Davis and others. The results of the Serbian studies, which were conducted at the Nuclear Medicine Department of the Medical Center in Jacecar Serbia, confirm the necessity of TSH receptor antibody tests to confirm Graves' disease. While a small number of Graves' cases may also have thyroid gowth immunoglobulins (TGI) in active Graves' mdisease more than 95 percent of patients will have stimulating TSH receptor antibodies, which are also known as TSI or thyroid stimulating immunoglobulins.

The principle behind these antibody tests is unusual. The TSI, TBII and total TSH receptor antibody test measure increased thyroid hromone levels in a test combining patient serum and animal thyroid cells; when serum samples contain these animals the thryoid hormone concentration changes; we report the difference in concentration of hormone produced during the test as a percentage of change. Because most lab tests measure the amount of a substance such as antibodies or hormones, these tests are easily misinterpreted....understandably, this is a difficult concept for many doctors to understand. Often, they want a positive or negative result based on the negative cutoff of 125 percent, which is seen in most patients with clinically significant symptoms of graves' disease. Considering normal people do not have these antibodies and their levels are reported as less than 2% activity, what would you suspect of someone with a TSI level of 110 % activity. A future blog will be added in the next week to describe this test interpretation.

It's a real step forward to see these Serbian researchers state that based on their work, TSH receptor autoantibody-negative Graves' disease is extremely rare, but misdiagnosis of GD when other thyroid conditions are present is common. Hence the need for the test.