Hyperthyroidism is an autoimmune disorder caused by the thyroid stimulating antibody (TSI), active against the thyroid-stimulating hormone (TSH) receptor, which stimulates the gland to synthesize and secrete excess thyroid hormone. It affects approximately 1.5% of the worldwide population. Graves’ disease is the most common cause of hyperthyroidism.
Fast and proper differential diagnosis of Graves’ disease is vital to initiating appropriate treatment as soon as possible. Patient history, physical examination, and diagnostic tools such as imaging and laboratory testing are necessary for proper diagnosis. Choosing the right laboratory tests and interpreting them correctly are critical components of Graves’ disease diagnosis. Currently, a variety of thyroid antibody and hormone assays are available. Understanding the differences between these tests is important to choosing the right assay.

Learning Objectives

• Understand how clinicians diagnose and monitor Graves’ disease, and why the TSI assay is beneficial from the clinician’s point of view.
• Learn about the differences between the TSI assay and a thyroid receptor antibody test called TRab. 
• Review the laboratory needs for proper Graves’ disease assessment.