Celiac News

Screening for Celiac Disease in a Pediatric Gastroenterology Clinic

A prospective evaluation was conducted of the recently developed IgA-tissue transglutamine antiboy assay (tTG) and the IgA-antiendomysial antibody assay (EMA) as screening tests for Celiac Disease in 75 IgA-sufficient and two IgA-deficient children, aged 2 months - 16 years. Children included those scheduled for small intestinal biopsy for the evaluation of abdominal pain, diarrhea, failure to thrive, short stature, IBD or vomiting or because of a family history of Celiac Disease.

Methods:

The IgA-tTGs (NOVA, La Jolla, CA) were measured by ELISA and the IgA-EMAs (Scimedes, Denville, NJ) were determined by immunohistochemistry. Intestinal biopsies were obtained with a Carey capsule or during upper endoscopy (4-6 distal duodenal biopsies) and read by a pathologist blinded to the screening results.

Results:

Seven of eight IgA-sufficient patients with biopsy proven Celiac Disease screened positive with both tests and one screened negative for both tests. The false negative IgA-sufficient child was 4 years and displayed symptoms of malabsorption.  Four IgA-sufficient patients displayed false positive tTG and two of these had false positive EMA assays. Two years later, one of these patients developed increased antibody titres and biopsy proven Celiac Disease. Sixty-five IgA-sufficient patients screened negative with both tests had biopsies not diagnostic of Celiac Disease. In the IgA-deficient children, both screening tests were negative. One had biopsy proven Celiac Disease and one did not. In IgA-sufficient patients for both tests, the sensitivity was 89% and the negative predictive value was 98%. The specificity of the tTG was 94% and EMA, 97%(ns). The positive predictive value of the tTG was 67% versus the EMA of 80%(ns).

Conclusions:

The IgA-tTG and the IgA-EMA antibody tests are equivalent screens for Celiac Disease in IgA-sufficient children. False positive patients need to be followed with repeat antibody testing because they may develop Celiac Disease. Small intestinal biopsy remains the gold standard for the diagnosis of Celiac Disease in children with malabsorptive symptoms, as evidenced by false negative screening in an IgA-sufficient patient.

Permission to reprint this abstract was kindly provided by Dr. Decker Butzner, member of the Canadian Celiac Association Professional Advisory Board.