Thyrotropin is a peptide hormone secreted by the pituitary gland that promotes the synthesis and secretion of thyroid hormones by the thyroid gland and regulates the secretory function of the thyroid gland through the hypothalamic-pituitary-thyroid axis. High-sensitivity thyrotropic hormone refers to a sensitive method of detecting thyrotropic hormone, which allows for timely detection of changes in thyrotropic hormone. Increased high-sensitivity thyrotropic hormone is mainly seen in the following cases: i. Pituitary diseases, when pituitary tumors or pituitary hyperplasia occur, the secretion of thyrotropic hormone by the pituitary gland increases, resulting in increased high-sensitivity thyrotropic hormone levels and the formation of pituitary hyperthyroidism; ii. Primary hypothyroidism, under normal circumstances thyroid hormones can inhibit the secretion of thyrotropic hormone by the pituitary gland, so when the thyroid gland is low, it can appear elevated levels of hypersensitive thyrotropic hormone.