TSH Receptor Antibody Blood Test (TRAb) – Graves' Disease

The TSH receptor antibody (TRAb) blood test is used to detect autoantibodies that target the TSH receptor on the thyroid gland. These antibodies mimic the action of thyroid-stimulating hormone (TSH), causing the thyroid to overproduce thyroid hormones. This test is primarily requested when Graves' disease is suspected, when a patient has unexplained hyperthyroidism, or when a clinician needs to distinguish Graves' disease from other causes of an overactive thyroid. It is also valuable in monitoring treatment response and assessing the risk of relapse or remission, particularly in pregnant women with a history of Graves' disease, as TRAb can cross the placenta and affect the baby's thyroid function.

The test is performed on a simple blood sample using an immunoassay technique. No special preparation is required, and the sample can be collected at any time of day.

Biomarkers included

• TSH receptor antibody (TRAb)

Why it matters

TRAb is the definitive marker for Graves' disease, the most common cause of hyperthyroidism. Identifying it confirms the autoimmune basis of the condition, guides treatment decisions (such as antithyroid drugs, radioiodine, or surgery), and helps predict the likelihood of remission or relapse. In pregnancy, TRAb testing is essential for assessing the risk of neonatal hyperthyroidism or hypothyroidism, allowing timely monitoring and intervention. Accurate diagnosis and monitoring with TRAb can prevent complications such as thyroid storm, heart rhythm disturbances, and adverse pregnancy outcomes.