CPT® Code 84445

The CPT® Code 84445 refers to the measurement of thyroid stimulating immune globulins (TSI) in a blood sample. This test is crucial for evaluating the presence and levels of TSI, which are autoantibodies produced by the immune system. These autoantibodies specifically bind to the surface of follicular cells in the thyroid gland, mimicking the action of thyroid stimulating hormone (TSH). As a result, they can lead to an overproduction and secretion of thyroid hormones, which is a hallmark of hyperthyroidism. The test is particularly significant in diagnosing conditions such as Grave's disease, Hashimoto's thyroiditis, and toxic multinodular goiter, all of which are associated with overactive thyroid function. The methodology employed for this test includes bioassay and chemiluminescence, both of which are advanced techniques used to accurately measure the levels of TSI in the blood, providing essential information for the diagnosis and management of thyroid-related disorders.