Celiac Disease Testing

Testing for celiac disease

The prevalence of celiac disease is now known to be greater than original estimates, with a prevalence of approximately 1% of the population. [Elson: 2004] There are apparently subtypes of individuals with celiac disease (e.g., those with gastrointestinal symptoms alone, those with systemic manifestations only, and those with both gastrointestinal and systemic symptoms) and the utility of the serologic testing to diagnose celiac disease in all groups is not known. Because celiac disease may present clinically in many different ways, there is no individual test that can diagnose or exclude celiac disease in any one patient. After a diagnosis of celiac disease has been made, final confirmation needs to be made by looking for a positive response to the gluten free diet by monitoring clinical symptoms (GI symptoms, growth decrease, weight loss).

Who should be tested?
  • Infants with gastrointestinal symptoms and growth problems soon after gluten is introduced into their diet
  • Children (and adults) with chronic gastrointestinal symptoms including diarrhea, weight loss, fatty stools, abdominal distention, etc.
  • Consider testing also in other individuals with unexplained symptoms such as short stature, iron deficiency anemia, delayed puberty, ataxia, chronic aphthous stomatitis, irritable bowel syndrome, etc.
  • Testing of all family members when there has been a positive diagnosis is not recommended at the current time
  • Testing needs to be done on a diet that includes gluten
  • Interpretation of testing in children 4 and under is more difficult than in older children
  • As false positives in failure-to-thrive children are fairly common, clinicians will often increase calorie intake first before testing for celiac disease so as not to commit them to unnecessary endoscopic small bowel biopsies.
  • The first step is serological testing; IGA antihuman tissue transglutaminase (TTG) and IGA endomysial antibody immunofluoresence (EMG) are more accurate than antigliadin antibody tests (AGA) which are not very specific or sensitive. Quantitative IgA needs to be done prior to celiac testing to determine which serologic test should be done.
  • Children under two: Test only if clinically very suspicious. Test for anti-gliadin IgA and IgG and tissue transglutaminase (tTG) IgA and IgG antibodies. Some clinicians will not do anti-gliadin antibodies.
  • Children older than two:Test for quantitative IgA first, and if it is sufficient, test for anti-tTG IgA; if IgA is not sufficient, test for anti-tTG IgG.
    • If serologic tests are negative: and the disease is still strongly suspected, a biopsy may be useful as the patient may have a selective IgA deficiency and the serological tests will be negative because of IgA deficiency, not just TTG and EMG. IgG TTG and EMG tests may be useful in IgA serologically negative individuals prior to going to biopsy
    • If serological tests are positive: Biopsies of the small bowel should be performed to confirm the diagnosis (unless the child has biopsy proven dermatitis herpetiformis). Multiple biopsies need to be performed because histologic changes may not be present everywhere. Marsh criteria or other standard criteria should be used in the pathology reports (see also [Donaldson: 2007] If serological results and biopsy results are both suggestive of celiac disease, the patient needs to be monitored for his/her response to the gluten-free diet.
    • If results are indeterminate, assessment of the genetic risk by testing for DQ2 and DQ8 HLA haplotypes can be performed. As 97% of the celiac population has one or both of these markers, a negative result on both makes it unlikely that the patient has celiac disease
The significance of positive serology without evidence of enteropathy (on a gluten containing diet) is unclear at this time. Research is underway to clarify this issue. Although there are anecdoctal studies suggesting improvement of these patients on a gluten free diet, this diet is not suggested at this time..

Authors & Reviewers

Initial publication: January 2014
Current Authors and Reviewers:
Author: Daniel Jackson, MD

Page Bibliography

Donaldson MR, Firth SD, Wimpee H, Leiferman KM, Zone JJ, Horsley W, O'gorman MA, Jackson WD, Neuhausen SL, Hull CM, Book LS.
Correlation of duodenal histology with tissue transglutaminase and endomysial antibody levels in pediatric celiac disease.
Clin Gastroenterol Hepatol. 2007;5(5):567-73. PubMed abstract
Duodenal histology correlation with serum markers for celiac disease in pediatric patients, from local authors.

Elson, C.O.
NIH Consensus Development Conference on Celiac Disease.
NIH Consensus Development Conference on Celiac Disease, 2004; Bethesda MD.
NIH Consensus Statement regarding the diagnosis and treatment of celiac disease.