Significance of thyroid microsomal antibody in Graves' disease.

Thyroid microsomal antibody (MsAb) was estimated in 48 patients with Graves' disease (15 newly diagnosed, 15 on drugs for about 4 weeks and 18 euthyroid with drug treatment) and twenty age and sex matched controls. The diagnosis of Graves' disease (GD) was based on clinical history, physical examination and thyroid function tests, viz. 131I uptake, thyroid scintigram and serum T3, T4 and TSH levels. MSAb was positive in 93.3% of newly diagnosed as well as hyperthyroid GD patients on drugs. Eighty-three percent euthyroid GD patients and 20% normal controls also showed MSAb positivity. The titres of newly diagnosed patients were significantly raised (P < 0.05) than those of euthyroid patients and controls indicating the diagnostic as well as prognostic significance of MSAb in Graves' disease.