TG and neoplasm: Thyroglobulin is secreted exclusively by follicular thyroid cells, and elevated levels after total thyroidectomy and RAI therapy may suggest tumor recurrence.9,30,31 Stimulation of TSH enhances Tg assay sensitivity, but the impact of this test on patient outcome is controversial.13,30 Of note is that anti-Tg antibodies are detectable in 15%–20% of patients,13,32 and their presence interferes with Tg assessment.