Blood draws for several kinds of diagnostic tests require you to fast for several hours. Eating or drinking anything besides water can skew the results, leading to you needing to be retested. You may ...

A person should only fast before a blood test if their doctor or healthcare professional specifically instructs them to do so. Not all blood tests require fasting. If a doctor or healthcare ...

You generally don’t need to fast before a thyroid test, but a healthcare professional may advise you to prepare in other ways. The thyroid gland sits at the front of your neck and helps control your ...