What is all involved in an endoscopy? Is is very invasive? Is is an instrument that would be put down my throat, and would it cause irritation? I am a singer, so would not want to cause irritation to my throat area. I have suffered from acid reflux for years, and tested positive for celiac disease in a blood panel, a little over 2 years ago. I have debated whether this test should be done on me, to determine if there could possibly be other problems as well.