A sensitive human thyroglobulin RIA to define clearly the presence or absence of functioning thyroid tissue.

This paper describes a practical procedure to establish a sensitive radioimmunoassay for the measurement of human thyroglobulin (HTg) in serum. The assay enables a clear distinction to be made between levels of HTg indicating the presence or absence of functioning thyroid tissue. It compares the use of HTg serum levels with the conventional I-131 scintigram as a marker for recurrent thyroid cancer. In addition, a simple and sensitive radioimmunologic assay is described for the determination of serum antithyroglobulin autoantibodies, the presence of which may give falsely elevated HTg levels.