Measurement of thyroglobulin in the circulation: clinical and technical considerations.

The concentration of thyroglobulin (TG) in the circulation can be measured by a sensitive, specific, convenient radioimmunoassay. TG is found in the circulation of virtually all normal subjects. It is present in elevated concentrations in patients with a wide variety of thyroid diseases including benign and malignant tumors, multinodular goiter, subacute thyroiditis, Graves' disease and others. At the present time, the most important clinical role of TG measurements is in the evaluation of patients who have been treated for thyroid cancer. As greater clinical correlation is obtained, the usefulness of TG determinations will increase. Anti-TG autoantibodies cause false results in the assay and present the major technical problem which needs to be resolved.