--there is no "smoking gun" as far as celiac goes, but that doesn't necessarily rule out gluten sensitivity or even celiac; as many as 20% of proven celiacs on intestinal biopsy test negative on the serologic assays.
They probably should have done separate anti-gliadin IgG and IgA tests, though--often an isolated positive on the anti-gliadin IgG can point to a gluten sensitivity with our without gastrointestinal symptoms.
Were there any other liver tests with out of range results? There are a lot of other reasons for a slightly elevated ALT/SGPT:
http://en.wikipedia.org/wiki/Alanine_transaminase
http://www.webmd.com/digestive-disor...ase-alt?page=2