Thyroid-stimulating immunoglobulins (TSI) can be detected in the majority of patients (77.8%) with Graves' disease. These antibodies have also been associated with a small portion (15.9%) of patients with toxic multinodular goiter. It has also been reported that TSI measurement can be used to predict relapse or remission when methimazole or radioiodine is used to treat Graves' disease. These assays have also been advocated for use in patients with subclinical Graves' hyperthyroidism or patients with unilateral ophthalmopathy.
This test can take 7-14 days for results. The test methodology uses a Chinese hamster ovary cell line transfected with both the thyrotropin receptor and a luciferase reporter gene.