Thyroid function tests generally include thyroid stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxine (FT4), and patients should pay attention to regular rest and diet before the test, inform the doctor if they are taking medications affecting the thyroid function, and patients who have been diagnosed with thyroid disease should take their medications normally. 1. Regular rest and diet: take rest, do not stay up late, choose a light diet and avoid consuming too much food with high iodine content before taking the blood test, so as not to affect the test result. 2. Inform the doctor if you are taking medications that affect thyroid function: medications such as glucocorticoids, dopamine, amiodarone, lithium, etc. may affect the results of the thyroid function test, so it is recommended to inform the doctor in advance before the test. 3. Patients with diagnosed thyroid diseases can take medication normally: if hyperthyroidism, hypothyroidism and other diseases have been clearly diagnosed and are receiving medication, the medication can be taken normally before the blood is drawn to objectively reflect the efficacy of the medication, which helps to monitor the condition. Thyroid function test can reflect the status of thyroid function and help the doctor to initially screen and diagnose thyroid diseases.