Esophagogastroduodenoscopy - try saying that 3 times fast (hell I couldn't say it 1 time fast!) - is the technical term for the procedure used to visualize the upper part of the GI tract in order to obtain biopsy samples. An edoscope, which is a long, narrow, flexible tube with a camera at the end of it (I'm simplifying) is passed through the mouth and down into the GI tract. This allows the endoscopist (doctor that's manipulating the tube) to observe the different sections of the GI tract and decide if and where to take biopsies. I had this done after my blood test came back positive for CD. The biopsies are looked at under a microscope to see if the villi are flattened, or atrophied. This procedure isn't as bad as it sounds; I got some good sedation, so I don't even remember it. Actually, I don't remember much of anything from that afternoon/evening, so maybe you don't want to go by my recommendation! Plus my dad told me I said the same thing to him 5 times in the 20 minute car ride - I'm sure I was great fun that day!
I was somewhat prepared for what was going to happen because I've seen several bronchoscopies done (similar procedure, only the bronchoscopist is going into the lung). I was still nervous though; seeing and actually having it done are 2 very different senarios! I can see how this procedure could potentially really freak someone out. That is one of the reasons that doctors are studying the use of a new "pill camera" to see into patient's small intestine to diagnose CD. This "pill camera" (aka capsule endoscopy) is simply swallowed by the patient and then it takes pictures with up to 8 fold magnification as it travels down the GI tract.
There are several advantages to this "pill camera", the obvious being it is minimally invasive and less scary to patients - it's just swallowing a pill, not a long tube. Additionally, more of the small intestine can be observed so that even if the damage happens to be past what the endoscope can reach, it will be detected. Also, it can be used to find if the patient has any long term complications from undiagnosed CD. And since it is minimally invasive, it could also be used after diagnosis to track healing.
There are some disavantages too. The procedure is relatively new, so many insurers will not cover it and there isn't a way to take a biopsy if needed with this camera. But this procedure is a great advancement for the diagnosis of CD.
A little off topic, but the thing I'm curious about - exactly how many people have a positive blood test, but negative biopsy? I don't know and I'm not sure what those test results would indicate, but I would be interested if anyone has seen any research on this.