T3 refers to triiodothyronine, T4 refers to thyroxine, and TSH refers to thyroid stimulating hormone.High T3, T4 and TSH may be caused by pituitary hyperthyroidism and other diseases. T3 and T4 are both thyroid hormones, and elevated levels of both suggest elevated levels of thyroid hormones in the blood. TSH is secreted by the pituitary gland and promotes the synthesis and release of T3 and T4, and elevated levels of TSH suggest elevated levels of thyroid-stimulating hormones. When T3 and T4 are high and TSH is high, it is considered that the lesion is located in the pituitary gland, suggesting pituitary hyperthyroidism, in which the pituitary gland will secrete excessive thyrotropin, which will promote the synthesis and release of T3 and T4, resulting in high T3 and T4 levels. If T3 and T4 are high and TSH is high, it is recommended to go to the hospital and ask the doctor to make a judgment and clarify the cause of the disease.