Intestinal biopsy is not always required to diagnose celiac disease: a retrospective analysis of combined antibody tests.
Background: The objective of this study was to compare celiac disease (CD)– specific antibody tests to determineif they could replace jejunal biopsy in patients with a high pretest probability of CD.Methods: This retrospective study included sera from 149 CD patients and 119 controls, all with intestinal biopsy.All samples were analyzed for IgA and IgG antibodies against native gliadin (ngli) and deamidated gliadin peptides(dpgli), as well as for IgA antibodies against tissue transglutaminase and endomysium.Results: Tests for dpgli were superior to ngli for IgG antibody determination: 68% vs. 92% specificity and 79% vs.85% sensitivity for ngli and dpgli, respectively. Positive (76% vs. 93%) and negative (72% vs. 83%) predictive valueswere also higher for dpgli than for ngli. Regarding IgA gliadin antibody determination, sensitivity improved from61% to 78% with dpgli, while specificity and positive predictive value remained at 97% (P < 0.00001). Acombination of four tests (IgA anti-dpgli, IgG anti-dpgli, IgA anti- tissue transglutaminase, and IgAanti-endomysium) yielded positive and negative predictive values of 99% and 100%, respectively and a likelihoodratio positive of 86 with a likelihood ratio negative of 0.00. Omitting the endomysium antibody determination stillyielded positive and negative predictive values of 99% and 98%, respectively and a likelihood ratio positive of 87with a likelihood ratio negative of 0.01.Conclusion: Antibody tests for dpgli yielded superior results compared with ngli. A combination of three or fourantibody tests including IgA anti-tissue transglutaminase and/or IgA anti- endomysium permitted diagnosis orexclusion of CD without intestinal biopsy in a high proportion of patients (78%). Jejunal biopsy would be necessaryin patients with discordant antibody results (22%). With this two-step procedure, only patients with no CD-specificantibodies would be missed.
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