TSH is thyroid stimulating hormone, which is one of the indicators of thyroid function, and elevated TSH is usually indicative of low thyroid, i.e., hypothyroidism, and needs to be combined with other indicators of thyroid function to make a diagnosis, such as free T3, free T4, and so on. Low free T3 and free T4 with elevated TSH are considered primary hypothyroidism, but if elevated free T3 and free T4 are accompanied by elevated TSH, then the presence of a TSH tumor in the pituitary gland or a rare disease such as thyroid hormone insensitivity syndrome is considered. Therefore, patients who are suspected of having hypothyroidism or hyperthyroidism need to consult a doctor in time and under the guidance of the doctor to have a thyroid function test, and according to the patient’s clinical manifestations and test results, a comprehensive analysis will be made to determine whether the patient is suffering from hypothyroidism or hyperthyroidism.