I am getting ready to have my thyroid tested because of rapid weight loss. I am currently taking prescribed Vicodin, will that affect my test in any way or appear in the test in any way?

It should not. Vicodin does not act in the function of the thyroid. If it is by prescription your doctor should already know you are on it, unless of course you are going to a different doctor. Then by all means take a list of all of your meds with you.