Generally, children at risk for celiac disease are screened at age 2 or 3 unless symptoms are seen beforehand. In children younger than 3, with symptoms, antibody testing may not always be accurate. Children must be eating wheat or barley-based cereals for some time, up to one year, before they can generate an autoimmune response to gluten that shows up in testing. A pediatric gastroenterologist should evaluate young children experiencing a failure to thrive or persistent diarrhea for celiac disease.
While a genetic test cannot diagnose celiac disease by itself, it can all but rule it out if neither of the genes are present, and a genetic test
can be done at any age. March, 2016