Serum thyroglobulin or thyroglobulin in fine-needle aspiration washout of metastatic lymph nodes: which one should we have confidence in for the surveillance of thyroid carcinoma?

S-Tg measurement is a less reliable method for follow-up in patients with thyroid carcinoma in comparison with FNA-Tg. For patients with negative S-Tg but suspicious features in US, FNAC combined with FNA-Tg is strongly recommended to confirm the diagnosis.