Is Thyroid Test Done on An Empty Stomach?

Thyroid is an important gland that produces thyroid hormones to support different functions in your body. The gland is located at the base of the neck, on the front side. It helps with healthy metabolism and promotes body’s growth and development. It also plays a vital role in regulating the body temperature, blood pressure and heart rate. Any issue with functioning of the thyroid gland can result in weight gain or loss, digestive issues, fatigue, heart conditions, etc. If you are advised to get requisite test done needed to diagnose the thyroid condition, then it may occur to you whether is thyroid test done on an empty stomach, or can you eat anything before the test? Read on to know more.

A thyroid test is done to check the functioning of thyroid gland and to determine the levels of different thyroid hormones in the blood. Any discrepancy in the levels indicates of a thyroid disease. So, should you get thyroid tests done on an empty stomach or is it fine to eat before the test?

Studies have shown variations in the levels of different thyroid hormones for tests that are done on an empty stomach vs. when done after eating. Therefore, your healthcare provider may ask you to fast before the test. This means that you must not eat or drink anything (water is fine) for at least 8 to 10 hours before the test.

There are three types of thyroid tests – TSH test, T4 test and T3 test. Since the TSH test is more reliable than T3 and T4 tests, TSH is always the first test done for thyroid patients.

What is the best time to be tested?

The best time to get tested for thyroid is in the morning on an empty stomach. The thyroid hormones fluctuate throughout the day. Therefore, it is recommended to always get tested for thyroid at the same time and in the same manner for accurate results.

Studies have shown a substantial drop in the TSH hormone levels during the day in both medicated and unmedicated individuals. For example, if patients with a low thyroid blood hormone are tested at 8 AM and 2 PM on the same day, there will be a substantial drop in the TSH levels in the test done at 2 PM. In this case, opting for an afternoon test can result in a missed diagnosis.