Thyroid hormone auto-antibodies interference in thyroid hormone assay

Objective: To detect and investigate how thyroid hormone autoantibodies interfere in thyroid hormone assays. Methods: The binding reaction, dilution testing, calibration curves and the check analysis were performed. Results: Thyroid hormone autoantibodies were measured and identified. The combination of the auto-antibodies with 125I-T3 or 125I-T4 were specific, the binding rates were 58.77% and 49.05% respectively, 7-12 times higher than control groups, while with 125I-TSH was non-specific. The radioactive peaks of the autoantibodies and rabbit anti- T3 or T4 antibody appeared at the same position. These antibodies were considered as IgG. Conclusions: The presence of anti-thyroid hormone antibodies is the primal cause of falsely high concentrations of serum thyroid hormones. Determination of thyroid hormone autoantibodies is importance in the diagnosis and treatment of thyroid disease