Anti-gliadin antibody panel and xylose absorption test in screening for celiac disease

We prospectively evaluated the use of a widely used commercially available anti-gliadin antibody (AGA) panel, and compared it with the xylose absorption test in screening pediatric patients with possible celiac disease for small intestinal biopsy. Sixty children were investigated with a 1-h xylose absorption test, IgG and IgA AGA panels, and small bowel biopsy; 15 patients were diagnosed with celiac disease. The xylose was sensitive (93%) but not specific (47%) for celiac disease. The IgA AGA test had high sensitivity (100%) but low specificity (58%), while the IgA AGA test had low sensitivity (53%) but high specificity (93%) in screening for celiac disease. We conclude that the AGA panel currently available in the United States is comparable to, but not significantly different than, the xylose absorption test when used as the only laboratory test in screening for celiac disease. A two-step screening process would have best improved our ability to predict celiac disease. We recommend screening with the AGA panel, and obtaining a xylose test if only the IgG is abnormal. Biopsies should be performed in cases with high IgA AGA, or with abnormal IgG AGA and xylose values. This approach is clinically preferable, does not add cost, and spares children from unnecessary small bowel biopsies.