European Journal of Gastroenterology & Hepatology
Original Articles: Coeliac Disease
Diagnostic accuracy of coeliac serological tests: a prospective study
Reeves, Glenn E.M.a; Squance, Marline L.a; Duggan, Anne E.a; Murugasu, Rajathurai R.a; Wilson, Robert J.b; Wong, Richard C.b; Gibson, Robert A.a; Steele, Richard H.c; Pollock, Wendy K.d the Multicentre Coeliac Study Group
aHunter Area Pathology Service (HAPS), John Hunter Hospital, Newcastle, NSW, Australia
bRoyal Brisbane Hospital (RBH), Queensland, Australia
cCanterbury Health, Christchurch, New Zealand
dGribbles Pathology, Victoria, Australia
eInstitute of Medical and Veterinary Science (IMVS), South Australia
fQueensland Medical Laboratory, Queensland, Australia
gImmunology Department, Fremantle Hospital, Fremantle, Western Australia
hRoyal Prince Alfred Hospital, NSW, Australia
Correspondence and requests for reprints to Glenn E.M. Reeves, Hunter Area Pathology Service, John Hunter Hospital, Locked Bag 1, Hunter Region Mail Centre, NSW 2310, Australia
Tel: +61 2 49214029; e-mail: [email protected]
Sponsorship: The study was partly supported by a grant from the Royal College of Pathologists of Australasia.
Received 14 October 2005 Accepted 14 January 2006
Abstract
Objective
The best way to test serologically for coeliac disease (CD) remains controversial, with endomysial (EMA), transglutaminase (TTG), and gliadin antibodies (AGA) being assessed in various combinations with no apparent standardization. The objective of this study was to evaluate whether TTG-IgA+/−TTG-IgG could be used as a replacement for endomysial antibodies as a reliable screen for CD in patients presenting to a major Australian tertiary referral hospital for assessment of symptoms consistent with CD.
Methods
Individuals referred for gastroscopic assessment of possible CD were prospectively evaluated by duodenal biopsy assessment. The following diagnostic methods were compared: dual-isotype transglutaminase (TTG-dual), combined-isotype transglutaminase (TTG-IgA+G), TTG-IgA, combined-isotype gliadin antibodies (AGA-IgA+G), AGA-IgA, and endomysial antibody assays. Clinical performance characteristics (sensitivity, specificity, area under the curve for receiver-operating characteristic analysis; AUROC) were assessed for all kits.
Results
The correlation between transglutaminase kits was generally good, with the best transglutaminase kit demonstrating high correlation (r=0.86) with endomysial antibodies. A comparison of different types of endomysial antibody assays displayed variable diagnostic performance (sensitivity 61.90–68.42%; specificity 80.00–98.57%; AUROC 0.71–0.83). Sensitivity (90.48–92.31%), specificity (80.77–82.89%) and AUROC values (0.92–0.94) for dual-isotype transglutaminase kits displayed narrow ranges. AGA assays were less sensitive (AGA-IgA: 42.31–46.15%; AGA-IgG: 61.54%) and less specific (AGA-IgA: 85.09–87.73%; AGA-IgG: 82.46–84.09%). Dual-isotype transglutaminase testing was diagnostically equivalent to transglutaminase-IgA (AUROC 0.92 versus 0.91, P=0.33).
Conclusions
Our study suggests that transglutaminase screening (using the IgA±IgG isotype) is a sensitive and specific alternative to endomysial antibody testing in the serological assessment of CD. On the basis of our findings, AGA antibody testing no longer appears to be an essential part of the diagnostic strategy for adult CD.