TG and differentiated thyroid carcinoma: IMA, MS, and RIA methodologies were used to measure serum Tg in TgAb-negative (TgAb−) and TgAb-positive (TgAb+) patients with either distant metastatic differentiated thyroid cancer (DTC) or hyperthyroidism (HY)—patients in whom a detectable serum Tg would be expected.