There are several different tests to diagnose thyroid dysfunction. Some may be done right in your doctor's office while others must be sent to labs in other cities or states. Which test you are having run determines where it goes and how long until you get all your results. Most labs can run a TSH and Total T4 on the spot. Some also do Total T3 and Free T4, but Free T3 usually has to go out and takes about 1 week to 10 days. Other thyroid tests such as antibodies etc may take an additional week.