[macobrien]

When I was diagnosed back in the mid 00s, the tests were:

- A blood test for elevated levels of tTG-IgA antibodies, which are produced by the celiac autoimmune reaction. This has something like a 5% false negative and 10% false positive rate, so it's generally a strong indicator but doesn't totally confirm the diagnosis. - An EGD/biopsy of the small intestine. The lining of the small intestine is damaged by anti-tTG antibodies in a way that's recognizable under a microscope.