TRAb (TSH receptor antibodies)
Antibodies that bind to and stimulate the TSH receptor on the thyroid - the hallmark of Graves' disease.
TRAb - TSH receptor antibodies - are autoantibodies produced by the immune system that bind to the TSH receptor on thyroid cells. In Graves' disease, these antibodies mimic the action of TSH and permanently stimulate the thyroid to produce more hormone, leading to hyperthyroidism.
Measuring TRAb in the blood is the most specific test for Graves' disease. A positive result, combined with clinical features of hyperthyroidism, strongly supports a Graves' diagnosis. TRAb levels often correlate with disease activity - typically high during active hyperthyroidism and lower during remission.
TRAb levels are also used to monitor treatment. Falling levels during antithyroid drug therapy may suggest the condition is heading towards remission. Very high TRAb during pregnancy is particularly important, as the antibodies can cross the placenta and temporarily affect the baby's thyroid.
Some laboratories measure TRAb as TSI (thyroid-stimulating immunoglobulins) - these terms are closely related and refer to the same underlying immune activity. Your doctor will interpret your specific result in context.
Related terms
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