An enzyme immunoassay for the detection of IgM antibodies to Helicobacter pylori in serum. Purified H. pylori antigen is coated on the surface of microwells. Diluted patients serum is added to the wells, and the H. pylori IgM specific antibody, if present, binds to the antigen. All unbound materials are washed away. Enzyme conjugate is added, which binds to the antibody-antigen complex. Excess enzyme conjugate is washed off and a solution of TMB Reagent is added. The enzyme conjugate catalytic reaction is stopped at a specific time. The intensity of the color generated is proportional to the amount of IgM-specific antibody in the sample. The results are read by a microwell reader compared in a parallel manner with calibrator and controls.