Thyroid-stimulating immunoglobulins (TSIs) are autoantibodies that bind to the thyroid-stimulating hormone (TSH) receptor on thyroid cells, resulting in Graves' disease (GD), the most common cause of hyperthyroidism. Recently published guidelines recognize the value of anti-TSH receptor antibodies, and a TSI test with high sensitivity and specificity for GD, recently cleared by the US Food and Drug Administration, is now available. Despite this, existing diagnostic algorithms for hyperthyroidism do not currently include TSI testing except in specific cases like pregnancy. The objectives of this analysis are to understand whether incorporating a test that specifically detects TSIs into existing algorithms results in cost savings and reduces time to diagnosis for payers and managed care organizations.