Thyretain TSI Reporter BioAssay detects TSI, the causative agent of Graves’ disease, in patient serum. Other thyroid receptor antibody (TRAB) assays are nonspecific in that they cannot differentiate between blocking and stimulating antibodies (immunoglobulins). Based on a novel genetically engineered cell line, Thyretain detects only stimulating immunoglobulins. The technology also enhances the sensitivity of the cell line, providing improved results over currently available assays.
The genetically engineered cell line in Thyretain expresses a modified version of the TSH receptor. TSI from a patient sample binds to this receptor and through a cyclic AMP-responsive promoter triggers the production of firefly luciferase. The luciferase can then be detected and compared to a reference value to provide a TSI result for the patient.