[Basic and clinical evaluation of EIA (pin immuno assay, PIA) kit for antithyroglobulin antibody (TGAb) and antimicrosomal (antiperoxidase) antibody (TMAb)].

Newly developed enzyme immunoassay kit (Pin Immuno Assay, PIA) for quantitative determination of serum antithyroglobulin antibody (TGAb) and antimicrosomal (-peroxidase) antibody (TMAb) was evaluated. The method utilizes the Sandwich ELISA principle with a unique micropin as solid phase coated with antigen. Reproducibilities assessed by intra- and interassay variation were less than 6.9% (CV) and 7.2% for TGAb or 4.2% and 6.0% for TMAb respectively. Changes in the first or second incubation time did not affect both TGAb and TMAb values. Upper normal limits obtained from 47 healthy subjects were 150 IU/ml for TGAb and 25 IU/ml for TMAb. Positive results in TGAb were obtained 60.0% in patients with Graves' disease and 80.0% in chronic thyroiditis and in TMAb 77.8% in Graves' disease and 66.7% in chronic thyroiditis. Patients with other autoimmune diseases such as SLE, RA were also found high incidence of positive results, 48.3% for TGAb and 65.0% for TMAb respectively. These results indicate that the nonradioisotopic assay technique for thyroid autoantibodies are useful in diagnosis of autoimmune diseases especially thyroid diseases.