Because antibodies persistfor several years, serologic testing for H. pyloriIgG has a specificity of less than 80% for activeH. pylori infection,23 and repeat serum IgG testingis not useful for assessing eradication. Testsfor antigen-specific IgA, IgG, and IgM in blood,urine, and saliva are no longer recommendedbecause they lack meaningful predictive value.