Reverse T3 (rT3) is a thyroid hormone that is produced by the body in response to certain conditions, such as stress, illness, and fasting. Here are some reasons why you may need to have your rT3 tested:
To evaluate thyroid function: rT3 levels can be used to evaluate thyroid function, along with other thyroid hormone tests, such as TSH, T4, and T3. High levels of rT3 may indicate a problem with thyroid function, such as hypothyroidism.
To diagnose certain conditions: rT3 levels can be used to help diagnose certain conditions, such as Wilson’s syndrome, which is a controversial diagnosis that suggests low body temperature and other symptoms may be caused by low thyroid hormone levels despite normal TSH levels.
To monitor treatment: rT3 levels can be used to monitor the effectiveness of thyroid hormone replacement therapy in people with hypothyroidism. High rT3 levels may indicate that the dose of thyroid hormone replacement needs to be adjusted.
It’s important to discuss the results of your rT3 test with your healthcare provider to determine if any additional testing or treatment is needed. Not all healthcare providers routinely test for rT3, so it’s important to discuss the test with your provider if you have concerns about your thyroid function.