This limitation arises from the presence of naturally occurring anti-thyroglobulin autoantibodies (TgAb) in a substantial portion of the population (10–30%), which can interfere with immunoassays, leading to erroneous measurement of underestimated Tg concentrations than the actual levels, especially in cases of differentiated thyroid carcinoma (DTC) recurrence. Here, TG is linked to differentiated thyroid carcinoma.