A Report on the International Transglutaminase Autoantibody Workshop for Celiac Disease

Abstract

Objectives-Measurement of transglutaminase autoantibodies (TGAA) is considered to be the most efficient single serologic test for celiac disease (CD) by the American Gastroenterological Association Institute. We hypothesized that a large international collaborative effort toward improving and standardizing TGAA measurement is both feasible and necessary. The primary aim of this workshop is to compare TGAA assays among various research and clinical laboratories and examine assay concordance and improve (and eventually standardize) the TGAA assay. Guarantor of the article: Edwin Liu, MD. Methods Specific author contributions:Marcella Li: performed the bulk of the labor with organizing/aliquoting the sera, shipping, and performing related assays; Liping Yu: responsible for the quality control of our radioassay and also helped with data analysis, trouble shooting, planning details of the workshop. Our laboratory was used as a "reference lab"; Claudio Tiberti: contributed sera to the workshop, helped plan initial stages of workshop and paper preparation; Margherita Bonamico: participated in data analysis and paper preparation; Iman Taki: in charge of collecting the bulk of our sera at the institution and organizing the workshop; Dongmei Miao: technician performed radioassay and also performed the assay to serve as a reference for other laboratories; Joseph A. Murray: organized the workshop and paper preparation; Marian J. Rewers: contributed sera for our laboratory and helped plan the workshop; Edward J. Hoffenberg: mentor for the senior author, provided help in planning the workshop and recruiting participants; Daniel Agardh: contributed sera for the workshop, data analysis, and paper preparation; Patricia Mueller: contributed the control sera for the workshop, data analysis, and paper preparation; Martin Stern and Ezio Bonifacio: planned the details of the workshop, data analysis, and paper preparation; Edwin Liu: organized the workshop, communication with participants, overseeing our laboratory, data analysis, and paper preparation. NIH Public Access Author ManuscriptAm J Gastroenterol. Author manuscript; available in PMC 2010 July 15. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript radiobinding assays. A total of 150 serum samples were distributed to each laboratory, with each laboratory receiving an equal aliquot that was coded and blinded, composed of 100 healthy control sera and 50 CD sera.Results-Laboratory sensitivity ranged from 69% to 93% and specificity ranged from 96% to 100%. By receiver operator characteristic analysis, the area under the curve (C index) ranged from 0.9488 to 0.9904. When analyzing for linear correlation, r-squared was as high as 0.8882 but as low as 0.4244 for the celiac samples between different laboratories performing ELISA.Conclusions-This transglutaminase autoantibody workshop allows for larger-scale international participation for the purposes of improving and eventually standardizing the TGAA assay with subsequent workshops.

Quality not quantity for transglutaminase antibody 2: the performance of an endomysial and tissue transglutaminase test in screening coeliac disease remains stable over time

“…EQA alone cannot evaluate local diagnostic performance, but can detect method-related changes, quality issues and major differences between methods. Review of the EQA data for EMA and TG2 tests from all manufacturers over the last 2 years demonstrate probable biological variation in responses in different assays for individual patient materials [10,26]. There is, however, no obvious advantage in terms of ease of quality control or quality assurance of one test over another when qualitative responses are compared.…”

Using umbilical cord blood stem cells for myocardial infarction and stroke is ethically challenging

“…For this workshop, assays reported sensitivities ranging from 82% to 93%, underscoring the marked variability in assay performance. 2 Given these findings, the lack of positive serology in a proportion of their biopsy-proven coeliacs could be assay dependent.…”

“…There is evidence to support both sides of this argument, derived from studies conducted in North America, England, Australia and South America, including increased deleterious haemoglobin content, increased incidence of jaundice and polycythemia in infants delivered using late clamping. [2][3][4][5] However, early clamping has been thought to possibly deprive the newborn of potentially needed red cells and iron. [2][3][4][5] Regardless, in the USA it has been common practice for more than 50 years to deliver infants utilising what would be termed early clamping.…”

“…[2][3][4][5] However, early clamping has been thought to possibly deprive the newborn of potentially needed red cells and iron. [2][3][4][5] Regardless, in the USA it has been common practice for more than 50 years to deliver infants utilising what would be termed early clamping. Anecdotally, there has been no evidence of significant harm to these infants.…”

Diagnosis of Celiac Disease

“…14 However, sensitivity (and to a lesser degree specificity) may vary among laboratories. 37 Because of its simplicity and overall good diagnostic accuracy, detection of IgA tissue transglutaminase antibodies is the serologic test of choice for the diagnosis of CD. 31,39 False positive tests are unusual with human substrates, especially at high titers.…”