Thyroid T3 refers to triiodothyronine, and a T3 level of 5.8ng/ml is on the high side. Due to different examination methods and reagents, the reference indexes are different in each hospital and need to be analyzed specifically. Under normal circumstances, the normal value of T3 is between 0.6 and 1.81ng/ml. When the patient’s test result is 5.8ng/ml, it means that it is higher than the normal value, which may be caused by hyperthyroidism, subacute thyroiditis or taking too much thyroid hormone replacement drugs. When the above situation occurs, the patient should go to the endocrinology department of the regular hospital for further examination, to clarify the cause of the abnormally high T3 level, and follow the doctor’s instructions for active treatment, so as to avoid delays in the condition, resulting in serious consequences.