Correlation of thyroid antibodies and cytologic features in suspected autoimmune thyroid disease

Six hundred forty-three patients with antithyroid antibody results were studied. Antithyroglobulin antibodies were found in 101, and antimicrosomal antibodies were found in 338 patients. Fine-needle aspiration biopsy, performed in 122 patients, yielded a satisfactory aspirate in 108 subjects. Significant antithyroglobulin and antimicrosomal antibody titers were found in 28 of 57 and 149 of 267 patients, respectively. In 65 patients with cytologically proved Hashimoto's thyroiditis, only 15 had positive antithyroglobulin antibody results (11 titers were 1:1,600 or higher), whereas 61 had positive antimicrosomal antibody results (50 titers were 1:1,600 or higher). Thus, cytologic diagnosis of Hashimoto's thyroiditis correlated better with antimicrosomal antibodies than with antithyroglobulin antibody titers. These data suggest that antithyroglobulin antibody determination offers no particular advantage over antimicrosomal antibody titers. In subjects with a clinical diagnosis of Hashimoto's thyroiditis and negative antibody results, fine-needle aspiration biopsy remains useful in establishing the diagnosis.