Inter- and Intra-assay Variation in the Diagnostic Performance of Assays for Anti-tissue Transglutaminase in 2 Populations.

Tissue transglutaminse-2 (TG2)-based immunoassays are the cornerstone of diagnosis in celiac disease (CeD), with a reported pooled sensitivity as high as 98%.1 However, a few small, single-center studies have questioned their sensitivity in clinical practice.2-5 Moreover, commercial kits use variable TG2 antigens,6 with cutoffs determined by using small, poorly defined populations. Variation in diagnostic performance of anti-TG2 assays in different racial and geographic populations has not yet been studied. We compared the interassay and intra-assay variations in diagnostic performance of 4 immunoglobulin (Ig)A-anti-TG2 assays in Canadian and Indian populations.