Abstract: The invention includes novel methodology for diagnosing immunologic food or drug sensitivities. A method for diagnosing food sensitivities includes using diagnoses of other related disorders as indicators in the diagnosis of the food sensitivity. Additionally, failure to respond to or a relapse after treatment for microscopic colitis with bismuth subsalicylate is disclosed as being a further indicator in the diagnosis of immunologic food sensitivity. Finally, the presence of certain HLA-DQ alleles, particularly HLA-DQ1,1; -DQ1,3; -DQ1,7; -DQ1,8; and -DQ1,9 as indicators in diagnosing immunologic food sensitivity is also disclosed by the invention. A method for food sensitivity panel testing (for sensitivities other than gluten sensitivity) by detecting IgA antibodies in serum is also disclosed. A method for testing stool samples for the presence of particular antibodies is also disclosed for diagnosing immunologic food sensitivities.