S1261 Serology Testing for Antibodies in Celiac Disease: Comparison of Multiplex Immunoassay and ELISA Methods

Abstract

Serologic tests are frequently ordered as the initial step in the diagnosis of celiac disease. Newly developed tests for deamidated gliadin antibodies and tissue-transglutaminase antibodies measured by enzyme linked immunosorbent assay (ELISA) have better accuracy than native gliadin antibodies for celiac disease. In contrast to ELISA, multiplex immunoassay measures multiple autoantibodies simultaneously thereby decreasing processing time and facilitating panel testing. In this study, we compared multiplex immunoassay and ELISA methods for diagnostic accuracy of deamidated gliadin antibodies and tissue transglutaminase antibodies. Serum samples from 92 biopsy-proven, untreated celiac patients (46% with total villous atrophy and 54% with partial villous atrophy) and 124 biopsy-proven non-celiac controls were tested by multiplex immunoassay (QUANTA Plex Celiac IgA and IgG Profile, INOVA Diagnostics, Inc) and ELISA methods (QUANTA Lite, INOVA Diagnostics, Inc) for deamidated gliadin IgA and IgG and tissue-transglutaminase IgA and IgG antibodies. The sensitivity, specificity and accuracy of each single test and the combination of tests are summarized in the table below. The combination tests did not increase the sensitivity dramatically. Diagnostic indices of the tests and the combination tests measured by multiplex methods did not differ significantly from those measured by ELISA. The two methods showed excellent agreement for all tests except tissue-transglutaminase IgG. In conclusion, the multiplex immunoassay method is as accurate as the combination of ELISAs for celiac disease diagnosis and has practical advantages for testing in the clinical laboratory. Diagnostic indices of serologic tests for celiac disease diagnosis by Multiplex versus ELISA methods