From the Guidelines
Thyroid Receptor Antibody (TRA) is a crucial diagnostic marker for distinguishing between thyroiditis and Graves' disease in patients experiencing thyrotoxicosis due to immune checkpoint inhibitors. When diagnosing the cause of thyrotoxicosis, particularly in the context of immunotherapy, testing for TRA can help differentiate between thyroiditis and Graves' disease, as the latter is often associated with the presence of thyroid-stimulating hormone receptor antibody (TRAb) or thyroid-stimulating immunoglobulin (TSI) 1. The clinical significance of TRA lies in its ability to mimic the action of thyroid-stimulating hormone (TSH), leading to excessive thyroid hormone production and hyperthyroidism in conditions like Graves' disease. Some key points to consider when evaluating the significance of TRA include:
- The presence of TRA can indicate Graves' disease, which is a rare but potential cause of thyrotoxicosis in patients treated with immune checkpoint inhibitors 1.
- Thyroiditis, on the other hand, is a more common cause of thyrotoxicosis in this patient population and is typically self-limiting, leading to permanent hypothyroidism after the thyrotoxic phase 1.
- Additional tests, such as radioactive iodine uptake scan (RAIUS) or Technetium (Tc)-99 m [pertechnetate] thyroid scan, may be necessary to rule out other causes of thyrotoxicosis and to guide management decisions 1.
- The classification of TRAbs into stimulating, blocking, or neutral antibodies based on their effect on the TSH receptor can also inform treatment decisions, including the use of antithyroid medications, radioactive iodine therapy, or thyroid surgery. In clinical practice, the detection of TRA can significantly impact patient management, particularly in the context of immunotherapy-related thyrotoxicosis, and should be considered as part of a comprehensive diagnostic workup 1.
From the Research
Significance of Thyroid Receptor Antibody (TRA)
- The Thyroid Receptor Antibody (TRA) is significant in the diagnosis and management of thyroid disorders, particularly Graves' disease and Hashimoto's thyroiditis 2, 3, 4.
- TRA testing is used to diagnose Graves' disease, which is an autoimmune disorder that causes hyperthyroidism 2, 4.
- The presence of TRA can also be used to differentiate between Graves' disease and other causes of hyperthyroidism 4.
- Studies have shown that TRA concentrations can decrease during treatment with methimazole, but the addition of exogenous L-thyroxine does not result in a greater decrease in TRA concentrations 5.
- The measurement of TRA can be used to predict the risk of relapse in patients with Graves' disease after treatment with methimazole 6.
Clinical Utility of TRA
- TRA testing is a useful tool in the diagnosis and management of thyroid disorders, particularly in patients with hyperthyroidism or hypothyroidism 3, 4.
- The clinical utility of TRA testing lies in its ability to differentiate between Graves' disease and other causes of hyperthyroidism, and to predict the risk of relapse in patients with Graves' disease 2, 6.
- TRA testing can also be used to monitor the response to treatment in patients with Graves' disease 5, 6.
Interpretation of TRA Results
- The interpretation of TRA results requires careful consideration of the clinical context, including the patient's symptoms, medical history, and other laboratory test results 3, 4.
- The presence of TRA can be indicative of Graves' disease, but it is not diagnostic on its own 2, 4.
- The measurement of TRA concentrations can be used to predict the risk of relapse in patients with Graves' disease, but it is not a guarantee of relapse or remission 6.