I would think as long as you are not giving a diagnosis you wouldn't be out of your scope. I would think that if someone was out of range on a vital, you would just inform them that they need to follow up with their MD. I know I do flu clinics during flu season, and I almost always work independantly, and if someone comes up to me that I don't feel comfortable injecting for whatever reason, I just tell them to see thier doctor for their flu shot.