TG and hyperthyroidism: In exogenous hyperthyroidism, which is caused by the intake of excess amounts of thyroid hormones, laboratory data will show a low serum level of thyroglobulin (by contrast, it is high in patients with endogenous hyperthyroidism) and there is hardly any 24‐h radioiodine uptake in the thyroid due to the suppression of TSH secretion (except in patients with some autonomously functioning thyroid tissue) [21].