Outside of normal limits: False positive/negative anti TG2 autoantibodies

Abstract

Detection of IgA-transglutaminase2 (TG2) autoantibodies has become the test of choice for the diagnosis and monitoring of celiac disease (CD), and is recommended as the serological 'gold standard' by most of the CD societies. Despite its wide acceptance and reasonable performance, several aspects are problematic and disputed. The normal range levels between positivity and negativity are modified, manufacturers' cut-off levels are extremely variable, far from matching in house determinations, insufficient standardization, inadequate reference protocols and no reliable quality assessment of the ELISA antibody (AB) kits for CD diagnosis and follow-up of dietary adherence. Numerous limitations exist in its detection, diagnosis, and follow-up capacities, resulting in frequent clinical circumstances when professionals encounter false positive and negative situations. The present review updates and discusses these facets and aims to extend our knowledge and help CD associated professionals to use the IgA-TG2 antibodies appropriately. We hope that the content of the review will stimulate the scientific community to explore and better delineate the role and functions of the AB and the industrial manufacturers to improve clinical performance of their diagnostic tests.