Difficult diagnosis of celiac disease: diagnostic accuracy and utility of chromo-zoom endoscopy.

BACKGROUND

Chromo-zoom endoscopy has been demonstrated to be valuable in assessing the degree of intestinal villous atrophy in patients with suspected celiac disease.

OBJECTIVE

To evaluate the diagnostic accuracy of chromo-zoom endoscopy in patients with difficult diagnosis because of nonconcordant test results and/or the confounding of a gluten-free diet initiated before an appropriate diagnosis of celiac disease and to compare the findings to a recent reference standard, the in vitro gliadin challenge test.

DESIGN

Prospective, case-control study.

SETTING

Tertiary-care referral hospital.

PATIENTS

Patients without celiac disease (negative control group, n = 9), patients with celiac disease (positive control group, n = 41), and patients with difficult diagnosis (n = 27).

INTERVENTION

Chromo-endoscopy with indigo carmine and endoscopic zoom-magnification were performed. Duodenal fragments were collected for the in vitro gliadin challenge test. The area under the receiver operating characteristic curve (ROC) was used for statistical analyses on accuracy.

MAIN OUTCOME MEASUREMENTS

Diagnostic accuracy of chromo-zoom endoscopy for detection of mucosal abnormalities in patients with difficult diagnosis.

RESULTS

Chromo-zoom endoscopy had a high accuracy for celiac disease diagnosis in analyses on negative controls and positive controls (area under roc = 0.99). In the difficult diagnosis group, the accuracy of chromo-zoom endoscopy was lower (area under roc = 0.83), but it increased after exclusion of patients with celiac disease on gluten-free diet (area under roc = 0.88).

LIMITATIONS

There was a 4% failure rate in the ability to cultivate biopsies. Also, the study was done at an academic medical center.

CONCLUSION

Chromo-zoom endoscopy has high accuracy for cases of difficult diagnosis of celiac disease but only in untreated patients with celiac disease.