Hi feelbad,Welcome to the Healing Well GERD forum! I don't have gastroparesis, but have heard from several forum members who have. I expect someone who knows more than I do will be by soon to answer your questions.
I expect you've been scouring the web for information and probably already saw this resource, but just in case...Here's information from a great source--the Mayo Clinic:
http://www.mayoclinic.com/health/gastroparesis/DS00612
I've had the test for it, and it's not at all difficult.
Good luck with your quest for information!
Very best wishes,
Denise