Low thyroglobulin is mainly seen in hypothyroidism and after resection of thyroid cancer. The normal reference range for serum thyroglobulin is characterized by a strong geographic variation, and may vary from one testing facility to another. Patients with congenital hypothyroidism suffer from thyroid follicular cell insufficiency, which causes a decrease in thyroglobulin. Clinical diagnosis can be clarified based on symptomatic manifestations, thyroid function, imaging and other tests. Low thyroglobulin is caused by the destruction of thyroid tissue after thyroid cancer resection, resulting in insufficient thyroglobulin-secreting cells in the thyroid gland. The presence of a previous history of thyroid surgery in the patient makes the diagnosis definitive. Prompt hospitalization is recommended in the presence of low thyroglobulin.