Do you need the official diagnosis? I used to think I needed the official "you have celiac disease" diagnosis from the doctor so I could explain my way of eating to my family. It turns out, they understand that I get miserable, depressed and feel terrible when I eat gluten. Therefor, I don't need the diagnosis because I get support from my family.
IMO, if you know you have a problem with X, it's insane to intentionally injure yourself. If you can't handle gluten, then don't eat it. It might just be an intolerance instead of Celiac disease. Either way, avoid it and you'll feel better.
That said, if it makes your life easier (medical insurance, family, friends, co-workers) and/or you want the official diagnosis then you might want to procede with the testing. If you don't get a positive diagnosis from this test, you might need to suck it up and damage yourself for the next month so it shows up on the next test.
Poke it quickly, with a stick.