INVITED COMMENTARY Serum thyroglobulin determination in the follow-up of patients with differentiated thyroid carcinoma

(Correspondence should be addressed to M Schlumberger) Thyroglobulin (Tg) is produced only by thyroid follicular cells. Following total thyroid ablation, it should be undetectable in serum and any detectable level then indicates the persistence or recurrence of neoplastic disease. This is the basis for the use of Tg as a post-operative tumor marker in the follow-up of thyroid cancer patients (1). The aim of follow-up is the early detection of persistent or recurrent disease, and this is made possible by the combined use of sensitive Tg measurement, neck ultrasound and a 131I total body scan (TBS) (2, 3). The results of Tg measurement are highly dependent on the method used. This paper therefore focuses ®rst on the methods used for the measurement of serum T