Just be sure to wear something that makes it easy to show your scar if anyone questions why you are shopping with us geezers.
Luckily I have my wife to shop for me as I don't know if my scar would convince anyone. The kidney scar is by my diagonal finger, versus the stretch marks from prednisone 30 years ago that are more visible.
They do the appointment thing at Quest as well. When people give me the dirty look, I tell them they can bypass the wait by going online and making an appointment.