What is the role of serologic testing in celiac disease? A prospective, biopsy-confirmed study with economic analysis.
OBJECTIVE
The optimal serologic tests for the detection of celiac disease and follow-up assessment remains controversial. Our aim was to evaluate all current immunologic assays for diagnosing celiac disease using the gold standard of duodenal biopsy. We also assessed whether tissue transglutaminase (tTG) antibody is a quantitative marker for histologic severity.


METHODS
Consecutive adult patients referred for gastroscopy without a previous known diagnosis of celiac disease were recruited (group 1). Concurrently, patients with a known diagnosis of celiac disease on a gluten-free diet for more than 1 year undergoing repeat duodenal biopsy were identified (group 2). All patients had duodenal biopsies and serologic analysis performed for immunoglobulin(Ig) A and antibodies to human immunoglobulin (Ig)A-tTG, IgA-gliadin, IgG-gliadin, and IgA-endomysial antibody.


RESULTS
Two thousand patients were recruited in the first group. Seventy-seven (3.9%) patients were diagnosed with new celiac disease. The sensitivity, specificity, positive predictive value, and negative predictive value for IgA tTG were 90.9%, 90.9%, 28.6%, and 99.6%. When adopting a 2-step approach using tTG first and then EMA the sensitivity, specificity, positive predictive value, and negative predictive value was 85.7%, 98.6%, 71.7%, and 99.7%, respectively. The use of nondeamidated IgA/IgG gliadin antibodies conferred no additional diagnostic benefit when considering the detection of adult celiac disease. In the second group 48 patients with celiac disease on a gluten-free diet were identified. Sixteen of 48 of these patients had persisting villous atrophy, but 7 of 16 (44%) had a normal tTG level.


CONCLUSIONS
IgA tTG alone is a sensitive marker for celiac disease. A normal tTG level does not predict recovery of villous atrophy in patients with celiac disease on a gluten-free diet.
Hopper
Andrew D
AD
Department of Gastroenterology, Royal Hallamshire Hospital, Sheffield, United Kingdom.
Hadjivassiliou
Marios
M
Hurlstone
David P
DP
Lobo
Alan J
AJ
McAlindon
Mark E
ME
Egner
William
W
Wild
Graeme
G
Sanders
David S
DS
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000888:Antibodies, Anti-Idiotypic / Q000032:analysis*; D001706:Biopsy / Q000191:economics* / Q000379:methods; D002446:Celiac Disease / Q000175:diagnosis* / Q000191:economics / Q000276:immunology; D003365:Costs and Cost Analysis; D003937:Diagnosis, Differential; D004386:Duodenum / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007136:Immunoglobulins / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012698:Serologic Tests / Q000191:economics* / Q000379:methods; D012720:Severity of Illness Index
D000888:Antibodies, Anti-Idiotypic; D007136:Immunoglobulins