FIGURE 2.

Basal serum (second-generation) thyroglobulin immunometric assay trends for disease-free, thyroglobulin autoantibody-negative papillary histotype (no radioiodine treatment). This figure shows serum basal Tg^2GIMA measurements (Beckman Access analyses of frozen archived specimens [37^▪▪]) made for 18 TgAb-negative PTC patients treated by thyroidectomy alone (no RAI treatment), maintained on long-term TSH suppression (<0.1 mIU/l), without evidence of recurrence at the end of follow-up. Panel (a) shows that during the early postoperative phase, all patients achieved a basal serum thyroglobulin below 0.5 μg/l by 6–12 months after thyroidectomy (Tx.). Panel (b) shows the stability of thyroglobulin secretion from normal remnant tissue when TSH is held constant (median within-person percentage coefficient of variation ∼30%). PTC, papillary histotype; RAI, radioiodine; Tg, thyroglobulin; TgAb, thyroglobulin autoantibody; TSH, thyroid-stimulating hormone.