Related tests: TSH, fT3, fT4, anti-thyroglobulin antibodies, anti-thyroid peroxidase antibodies
Clinical significance
TSH receptor-stimulating antibodies (formerly called LATS, long-acting thyroid stimulator) belong to the IgG class of immunoglobulins and activate the membrane adenylate cyclase system of the TSH receptor, leading to the production of thyroid hormones.
The secretion of anti-TSH receptor antibodies is the underlying cause of hyperthyroidism in Graves’ disease.
Clinical indications
Graves’ disease, Graves’ ophthalmopathy.
Sample type
The patient must have a blood sample taken.
Preparation
You must fast for at least 8 hours; a small amount of water is allowed. You must have been standing or sitting upright for at least 30 minutes.
Notes
TRAb testing is useful for confirming Graves’ disease and, above all, for predicting the likelihood of relapse after prolonged antithyroid treatment (methimazole and propylthiouracil).
Persistently high TRAb levels at the end of prolonged treatment, usually lasting 12-18 months, suggest that relapse is likely. Conversely, a fall in TRAb levels during antithyroid treatment points to remission of the disease.