There will be a lot of people who try to tell you what to do in your practice. Some people are concerned about compensation, others about medicolegal issues. Some people are just darn ornery.
Bottom line: you're the doctor. If you need the test, get it. You may have to fudge your documentation slightly, bend a few truths, yell, scream, or do whatever is necessary.
Of course, you have to choose your battles. You can't do this every time.
I've worked in a lot of different ERs. When you first show up, you have to softshoe it and win the team's respect, meaning you have to play by their rules for a little while. You will change your practice slightly in every different place you work. After you understand the system, then you teach them how you practice.