No test can predict remission but there are some indicators. Looking at the level of antibodies can be helpful. TSI index determines patient’s immune system status. A decrease in TSI index and stable Thyroid stimulating hormone (TSH) levels (normal for six months) may indicate possible remission. Usually TSI index should decrease with antithyroid drug therapy and high value of TSI index after the conclusion of drug therapy may predict a relapse. Unfortunately, a low TSI index does not necessarily predict a long term remission. Some doctors taper the antithyroid medication dose slowly over a few months and observe TSH levels. It is important to say that TSH levels may remain undetectable for a while even though a person might have normal thyroid hormonal levels due to the activity of antibodies.
New research developed Mc4 assay to serve as a more sensitive index of remission or relapse of Graves’ disease.
Kamijo K. Murayama H, Uzu T, Togashi K, Kahalt G J. A novel bioreporter assay for thyrotropin receptor antibodies using a chimeric thyrotropin receptor (mc4) is a more useful in differentiation of Graves’ disease from painless thyroiditis than conventional thyrotropin-stimulating antibody assay using porcine thyroid cells. Thyroid. 2010 Aug:20(8):851-6.