TG and Hashimoto thyroiditis: It should be noted that data are lacking regarding the appropriate level of serum TSH for evaluation of Tg change, and that TSH suppression to below 0.1 mIU/L in all patients is contrary to current guidelines which instead recommend a range from <0.1 to 0.1–0.5 mIU/L to normal depending on individual risk.4 Patients with anti-Tg antibodies, defined by using cutoff values set for Hashimoto thyroiditis, were also excluded; the diagnostic cutoff level for anti-Tg antibodies in Tg kinetic studies and whether these patients should be excluded in such studies are not clear.