Blood antibody tests can give false negatives.
Small intestine biopsies can give false negatives.
And you have to be eating the equivalent of 6 slices of bread a day for weeks before the test.
The "gold standard" in the US is the small intestine endoscopic biopsy. Expensive. Kind of harsh on the body. Twilight anesthesia. False negatives.
The "gold standard" for the rest of the known universe is an extremely strict 2 week ABSOLUTELY gluten free diet. If you feel better after 2 weeks, you have celiac, eat carefully for the rest of your life.
There are also genetic tests which are highly accurate, but insurance doesn't pay for them. Last I heard those were $2,000 or so.
Lots of info in this looooong thread:
http://forums.teamestrogen.com/showt...ghlight=celiac