What are the sensitivity and specificity of serologic tests for celiac disease? Do sensitivity and specificity vary in different populations?

A number of serologic tests are available commercially for identifying individuals who require an intestinal biopsy examination to diagnose celiac disease (CD). The aim of this study was to determine which test, or combination of tests, was most sensitive and specific for this purpose. We performed a literature review of studies that determined the sensitivity and specificity of serologic tests for CD. Studies that compared biopsy examination-confirmed cases of CD with controls with normal intestinal histology were selected for analysis. Sensitivities and specificities for the antigliadin tests were highly variable. Immunoglobulin (Ig)G-based antigliadin (AGA) tests generally were poor in both parameters whereas the IgA-based test was poorly sensitive but more specific. The IgA endomysium (EMA-IgA) and tissue transglutaminase (TTG-IgA) tests were both highly sensitive and specific with values for both parameters exceeding 95% in most studies. There were no identifiable differences between adults and children with respect to these tests. There was no evidence that a combination of tests was better than a single test using either the EMA IgA or TTG IgA. Either the EMA-IgA or TTG-IgA test is most useful for identifying individuals with CD. The variability and generally lower accuracy associated with the AGA tests make them unsuitable for screening purposes. There is no advantage to using a panel of tests as opposed to a single test. Because these data were obtained largely from studies conducted in a research setting, it is possible the tests will be less accurate when used in the clinical setting.