CURRENT STATUS AND PERFORMANCE GOALS FOR SERUM THYROGLOBULIN ASSAYS

Serum thyroglobulin (Tg) measurements are used as a tumor marker for m onitoring patients with differentiated thyroid carcinoma. The clinical utility of six different Tg methods [RIA or immunometric assay (IMA)] currently used in Europe and the US was evaluated, with focus on meth odologic standardization, sensitivity, interassay precision across the typical clinical monitoring interval (6 to 12 months), ''hook'' effec ts (IMA methods), and Tg autoantibody interference. The methods evalua ted were: DYNOtest Tg (Henning), OptiQuant Tg (Kronus), SELco Tg (Medi pan), Thyroglobulin IRMA (Pasteur), Nichols Chemiluminescent ICMA (Cor ning Nichols), and an RIA developed by us (USC Endocrine Services Labo ratory). The clinical impact of the current methodologic problems on t he use of serum Tg measurements is reviewed. Optimal performance goals are recommended for manufacturers developing and laboratories and phy sicians selecting a serum Tg method to use for serial long-term monito ring of thyroid cancer patients.