<<Disclaimer: Verify this information before applying it to your situation.>> These descrepancies are of two, types 1. Blood test positive - biopsy negative: the antibody tests could be false positive ( some times happens especially with gliadin IgG ) , the antibody test may reflect a latent gluten sensitivty that ha s not done any damage ( by definition this individual should have no symptoms), or the biopsy is wrong because of too small a sample , just one taken , or an error in interpretation due to lack of awareness on the part of the pathologist of subtle changes of celiac disease ( marsh MN , gastroenterology, feb 1992. ) 2. Blood test negative and biopsy positive: the blood test might have preformed incorrectly or if gliadin alone is used it does not pick up all celiacs. The blood test may also go negative if gluten has been reduced in the diet before it is drawn. If the patient is IgA deficient it will often be negative. The other possibility is that it is not celiac disease on the biopsy there are some other things that can mimic celiac disease on biopsy. All in all no tests are perfect Joe Murray