Elevated TSH (thyroid-stimulating hormone) alone cannot directly determine hypothyroidism, but should be combined with T3 (triiodothyronine) and T4 (tetraiodothyronine) levels to make a comprehensive judgment. 1. Hypothyroidism can be diagnosed if there is a high TSH and a concomitant decrease in T3 and T4 levels, as well as symptoms such as fatigue, lethargy, and chills. 2. Subclinical hypothyroidism is diagnosed when TSH is high but T3 and T4 levels are normal and there are no obvious symptoms such as fatigue, lethargy and chills. 3. If TSH is high and T3 and T4 levels are elevated, central hyperthyroidism caused by pituitary factors should be considered. There may be other reasons for TSH elevation, so when TSH elevation occurs, you should go to the hospital and ask the doctor to analyze and judge, and should not blindly judge the treatment on your own.