Bioassays, shorthand for biological assays, are conducted in biomedical laboratories to measure the effects of a substance in or on a living organism. Bioassays are used to determine the concentration of biological activity of a substance such as antibodies and viruses.
Quidel provides a bioassay, called the Thyretain® assay that uses the firefly luciferase gene as a reporter. Thyretain cells express a human chimeric thyroid hormone receptor. When the serum from a patient tested by the assay contains the thyroid-stimulating immunoglobulin (TSI), the TSI binds to the receptor on the cell surface and triggers the luciferase gene expression, which can be quantitatively measured. Therefore, Thyretain can be used to diagnose Graves’ disease.