TSH Receptor Antibodies (TRAb)

TSH receptor antibodies (TRAb) are autoantibodies that bind to the thyroid-stimulating hormone receptor on the thyroid gland, mimicking or blocking the action of TSH. This test is used to investigate and monitor autoimmune thyroid disease, most notably Graves' disease, where stimulating antibodies drive overproduction of thyroid hormones. It is also valuable in distinguishing Graves' disease from other causes of thyrotoxicosis, in assessing the risk of relapse after antithyroid treatment, and in monitoring pregnant women with a history of Graves' disease, since these antibodies can cross the placenta and affect the baby's thyroid function. The test is performed on a simple blood sample using an immunoassay method.

Biomarkers

• Anti-TSHR (TRAb): Detects and quantifies antibodies directed against the TSH receptor. Elevated levels are characteristic of Graves' disease and can also be seen in some cases of autoimmune thyroiditis. The result helps confirm an autoimmune basis for thyroid dysfunction, guides treatment decisions, and predicts the likelihood of relapse or remission.

Why it matters

Identifying TRAb gives clinicians a precise, disease-specific marker for autoimmune thyroid disease. It clarifies the diagnosis when thyroid function tests alone are ambiguous, supports decisions about antithyroid drugs, radioiodine, or surgery, and helps protect both mother and baby during pregnancy by flagging antibodies that could affect the developing thyroid.