Patients may or may not take medication on the day of the thyroid function review. This is because taking medication on the day of the review does not have much effect on the results of the test on that day. The review of thyroid function on the same day only depends on the effect of the medication taken during the previous period of time, and it is not the case that the medication on the same day will affect the thyroid function on the same day of the review. So whether you have hyperthyroidism or hypothyroidism, you can take your medication or not when you go to the hospital to review your thyroid function, and this will not have a major impact on the results.