Improved measurement of anti-thyroglobulin IgG in urine of patients with autoimmune thyroid diseases by sensitive enzyme immunoassay (immune complex transfer enzyme immunoassay.

Previously, antithyroglobulin IgG was assayed in dialyzed urine from patients with autoimmune thyroid diseases by a sensitive enzyme immunoassay (immune complex transfer enzyme immunoassay), and most of the assay results were useful as a diagnostic aid for autoimmune thyroid diseases. However, dialysis of urine was laborious and time-consuming, and some results were less reliable due to low levels of anti-thyroglobulin IgG in urine. This paper describes some improvements of the assay. Useful assay results could be obtained for most of urine samples without dialysis, although some interfering substance(s) was suggested to be present in some urine samples before dialysis. Accurate assay results with no interference could be obtained after gel filtration by only two min centrifugation in place of dialysis. More reliable assay results for urine samples containing low levels of antithyroglobulin IgG were obtained after concentration using a molecular sieve.