My 11 y/o son had blood work recently and the IGA came back at 66 (it says the range should be 70-380 mg/dL). He is asymptomatic, height/weight are in the 97th percentile for his age. Doesn't complain about stomach issues ever. Looked at his bloodwork from last year and the number was the same. Is IGA a definitive dx tool for celiac? Does the 70-380 range adjust for peds? Just wondering.