Thyrotropin Receptor Ab, Serum

If you test positive for the Thyrotropin Receptor Ab, you likely have Graves' disease. If not, your healthcare provider may do other tests to determine whether you have Graves' or another condition, depending on how your other thyroid hormone levels are.

The Thyrotropin Receptor Ab test detects the autoantibody that's associated with Graves' disease. An antibody is a specialized protein made by your immune system. Antibodies are custom made to kill pathogens in your body, such as viruses or bacteria.

Thyrotropin is also called thyroid-stimulating hormone, or TSH. TSH binds to receptors on the thyroid gland to tell it to produce thyroid hormone. The thyrotropin receptor antibody mimics TSH, so when it's present, it directs the thyroid to keep releasing hormone when your body doesn't need it. That results in high levels of thyroid hormones, which is what causes symptoms. If the thyrotropin receptor antibody is present, it's an indicator of Graves' disease.