Diagnosis of celiac disease in adults based on serology test results, without small-bowel biopsy

Celiac disease is underdiagnosed, with nonspecific symptoms and high morbidity. New diagnostic factors are needed. We aimed to estimate the frequency at which adult patients with positive results from serology tests are referred for small-bowel biopsies and to identify factors that improve the diagnosis of celiac disease.

We performed a retrospective analysis of data from 2477 subjects who received serology tests for celiac disease between 2005 and 2007. We analyzed results for total levels of IgA, IgA against human tissue transglutaminase (hTTG), IgA and IgG against gliadin, as well as dilution titers of IgA against endomysial antibodies (EMA). Biopsy samples were analyzed by pathologists experienced in detecting mucosal changes associated with celiac disease and graded according to the Marsh system.

Of the 2477 patients, 610 (25%) had abnormal results from serology tests, and 39% of these patients (240 of 610) underwent small-bowel biopsy analyses. Of these patients, 50 (21%) had biopsy findings consistent with celiac disease (Marsh 3 lesions) and were placed on gluten-free diets. Titers of IgA hTTG greater than 118 U identified patients with celiac disease with a 2% false-positive rate. Titers of 21 to 118 U, in combination with an EMA dilution titer of 1:160 or greater, had a positive predictive value of 83% for celiac disease. IgA hTTG levels less than 20 U, in combination with an EMA dilution titer less than 1:10, had a negative predictive value of 92% for celiac disease.

Serum levels of IgA hTTG greater than 118 U, or 21 to 118 U in combination with an EMA dilution titer of 1:160 or greater, can be used to identify adult symptomatic patients with celiac disease, in the absence of a small-bowel biopsy.