What does it mean when thyroid globulin is low and antibodies are high?

Low thyroglobulin (Tg) levels combined with high anti-thyroglobulin antibodies (TgAb) suggest a relatively high likelihood of Hashimoto’s thyroiditis or hyperthyroidism.

1. Hashimoto’s Thyroiditis

Thyroglobulin is a glycoprotein synthesized by thyroid follicular cells. In patients with Hashimoto’s thyroiditis, in addition to low Tg and elevated TgAb, thyroid peroxidase antibodies (TPOAb) are also frequently increased.

2. Hyperthyroidism

Prolonged exposure to ionizing radiation, excessive use of interferon or iodinated contrast agents, or underlying conditions such as diabetes mellitus may predispose individuals to hyperthyroidism. These factors can lead to the abnormal laboratory finding of low Tg with high TgAb. Additional clinical manifestations may include nail thickening or neck enlargement (goiter).

Patients presenting with low Tg and high TgAb should promptly seek medical evaluation at a hospital. Under physician guidance, appropriate diagnostic tests should be performed to determine the underlying cause. Once confirmed, targeted pharmacologic therapy should be initiated to normalize thyroid hormone levels, thereby alleviating the aforementioned symptoms.