The TSH Receptor Antibody (TSHR-Ab) test detects antibodies that target the thyroid-stimulating hormone (TSH) receptor, which can interfere with normal thyroid function. This test is particularly useful in diagnosing and managing autoimmune thyroid diseases, such as Graves' disease, which often presents with hyperthyroidism. Elevated TSH receptor antibodies suggest an autoimmune process that stimulates excess thyroid hormone production. Results can help guide treatment and assess the likelihood of remission or relapse in Graves' disease.