There are many causes of high thyrotropin, such as primary hypothyroidism with hypothyroidism in Hashimoto’s disease, exogenous thyrotropin-secreting tumors (e.g., lungs, mammary glands), and recovery from subacute thyroiditis. Thyroid hormone can also be increased by ingestion of lithium metal, potassium iodide, and thyrotropin-releasing hormone. The normal range of thyrotropin is 0.35 to 5.5μIU/ml. Due to different examination methods and reagents, the reference indexes are different in different hospitals and need to be analyzed specifically. Once abnormal thyrotropin levels are detected, it is recommended to seek timely medical treatment under the guidance of a professional physician to avoid delaying the condition and causing serious consequences.