I've never heard of a positive DGP IgA being caused by anything other than celiac. I find it surprising that it's specificity is 93-96%, I expected it to be higher.... But with those numbers you have a bout a 5% chance that your positive test was caused by something else. If you have no celiac symptoms, and do not experience an improvement of your symptoms on the gluten-free diet, then it is possible you are one of the 5% who has something else. Chances are good it's celiac though.
A biopsy is not necessary if you are unable to complete a gluten challenge. Most doctors won't make you torture yourself with gluten if it's really hard on you. What has the doctor said about skipping the biopsy?
Sometimes doctors want all the stars, moons, and planets to align before they will give a diagnosis. If they won't diagnose you, and won't help you with whatever else they think is wrong, I think you should move ahead and start treating yourself for celiac. You might want to have nutrients tested as celiacs are often low in iron, ferritin, potassium, calcium, D, B12, and zinc. You might want to check out your thyroid (TSH, Free T4 and Free T3) as many celiacs have thyroid issues.
I've had a lot of blood work and nothing is coming up abnormal. I'm slightly anemic and my potassium is low, but other than that the doc said everything is functioning the way it should be. They just couldn't figure out why I had a severe rash and they might not ever know. Same with an allergic reaction I had a few months ago. Its just very scary. I do believe I have Celiac because 90% of my problems went away after going gluten-free, but new things have developed and that is what scares me. I'm so afraid of cancer and lupus and even RA, but my doctor doesn't think I have any of those Lets just hope he's right. Thank you so much for your input