[TSH receptor antibody measurements--the progress and the point at issue]

A half century has passed since Adams and Purves discovered the long acting thyroid stimulator which is now known as TSH receptor antibody (TRAb). The progress and the point at issue in measurement of TRAb is reviewed. Second generation TRAb assays based on inhibition of labeled TSH binding to TSH receptors coated on tubes or plate wells are available in clinical use, and show sufficient sensitivity and specificity for the diagnosis of Graves' disease. A highly sensitive thyroid stimulating antibody assay based on stimulation of cAMP release from frozen porcine thyroid cells is also available, and is useful for the evaluation of Graves' ophthalmopathy. Third generation TRAb assays and automated TRAb assays are developing.