The IV is for "rescue medications" in the event of an adverse reaction and gives the team immediate access to treat you with meds that can be vital! At our hospital I work out, it is just generally used per hospital policy or on the ordering physicians standard orders. Definitely talk to your dr to request to opt out if you think it will help calm you. It was reassuring to me! I had my last TTT in November 2016, with an IV, but the team was great and brought up a NICU nurse to stick me. She got it on the second try, a record for me! I was tilted up for 10 minutes and had that awful feeling we get when we feel like we need to lie down, but they were not allowed to lay the table down (generally the parameters of your vitals are set by your doctor ahead of time on this, for example, if your HR went to 200, you get to lie down!). My test was still inconclusive at 10 mins, so I was then laid back down, my IV was flushed and checked and the nurse went to get my cardiologist, who was in the room while the drug injected to stress the heart was administered, I was tilted back up for 10 more minutes and allowed to lie down when I fainted. It wasn't nearly as bad as others I have had over 20 years, like some that caused vomiting (BE SURE YOU ARE NPO AFTER MIDNIGHT TO AVOID THAT!) Sometimes, a simple request to your doctor or nurse will allow you to avoid parts of the test that scare you. It is so worth having a clearer diagnosis, so just keep in mind that this test is giving more knowledge to your treatment team and knowledge is power! You can do this!!!!