Thyroid function tests are generally used to determine thyroid function, whether it is hyperthyroidism or hypothyroidism, or a normal thyroid state. Thyroid function tests, which include thyroxine, triiodothyronine and thyrotropin, provide a basic indication of the functional status of the thyroid gland. In the case of hyperthyroidism, there may be elevated thyroxine and triiodothyronine and lowered thyrotropin. Symptoms such as palpitations (rapid heartbeat, often accompanied by panic), sweating, shaking of hands, excessive eating, and loss of weight are usually present. In the case of hypothyroidism, a form of hypothyroidism, there may be a decrease in thyroxine and triiodothyronine and an increase in thyroid stimulating hormone. Slow heart rate, chills, sleepiness, and lack of energy are usually present. The results of thyroid function need to be evaluated by a professional endocrinologist based on the patient’s clinical symptoms, physical examination and laboratory tests to make a diagnosis and treatment. If you feel unwell, please consult a doctor promptly.