We have improved the enzyme-linked immunosorbent assay for IgA-class antibodies to gliadin in serum by evaluating earlier publications. We also assess the value of measuring these antibodies when screening for adult celiac disease and monitoring dietary compliance. Of 61 adults with untreated celiac disease, 57 had abnormal results, giving a sensitivity for the test of 0.93. Patients (n = 283) attending a gastroenterology clinic formed the control group. The predictive values of positive results and negative results were 50% and 99.7%, respectively, indicating that the test has a role in helping select those subjects in whom small bowel biopsy is indicated. Adults with celiac disease, after two years on a strict gluten-free diet, and normal subjects showed no significant difference in serum IgA-class anti-gliadin antibody concentrations. The test thus provides objective evidence of dietary compliance in addition to its role as a screening test.