Blood tests and IgA deficiency

Hello I've been referred for a gastroscopy for coeliacs but my TTG was negative and my total IgA was really pointless it just said >0.0005 g/L when NICE guidelines say IgA deficiency is if <0.7g/L and that if TTG negative then need to test if person is IgA deficient. I don't want gastroscopy if I don't need one and am so frustrated that apparently in Wiltshire they don't follow the NIcE guidelines for coeliac testing! Any one got advice or experience please?