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In a recent review, gastroenterology experts explored opportunities to improve both biopsy and non-biopsy-based diagnostic processes for celiac disease.

A growing body of data supports a biopsy-free approach to diagnosing celiac disease (CeD) in specific scenarios. A recent review published in Gastroenterology provides an overview of the evidence behind nonbiopsy diagnosis and advice for improving both biopsy-free and biopsy-based approaches.

“There is a diversity of opinion regarding whether and how to adopt a nonbiopsy approach, both in the CeD community at large and among the authors of this article,” wrote Carolina Ciacci, MD, and colleagues. “Our purpose is not to recount the points of contention or the relative merits of a biopsy or nonbiopsy approach. Rather, it is to describe areas where both approaches could improve in the years ahead.”

According to the review, the accuracy of anti-tissue transglutaminase (TTG) IgA testing for predicting mucosal atrophy in patients on a regular gluten-containing diet has paved the way toward more biopsy-free CeD diagnoses. Specifically, TTG IgA at 10 times or more the upper value of normal can signal CeD.

“To make a comparison, a 10-fold–elevated TTG has a positive predictive value in the diagnosis of CeD stronger than the dynamic change in fasting blood glucose in 2 samples in the diagnosis of diabetes,” the review reported.

Nonbiopsy diagnosis, however, requires highly elevated TTG IgA levels, which clinicians need to understand. The authors also proposed the need for a common standard for normal ranges of the several TTG tests currently available worldwide. They wrote that developing an international calibrator with a defined concentration of TTG IgA for assay standardization would improve assessment.

For the many patients with TTG IgA short of a 10-fold elevation, broad consensus continues to support duodenal biopsy as a key component for CeD diagnosis. To maximize diagnostic utility, the minimum clinical data set clinicians need to communicate to the pathologist includes the reason for endoscopy, designation as diagnostic or follow-up biopsy, serology if available, gluten consumption status, medications, and site of biopsies.

Due to patchy distribution of mucosal injury, guidelines recommend two biopsies from the first duodenum and four biopsies from the distal duodenum.

“Despite these recommendations, adherence to biopsy guidelines in the United States appears to be low,” researchers wrote, “presenting an opportunity for improvement.”