Denis Chang, MD: Standardizing Celiac Disease Diagnostics

A new study from a team of US investigators is observing the performance of North American-based serologic assays for diagnosing celiac disease using thresholds set by their European colleagues.

The study intends to observe the frequency of biopsies in children deemed at high risk of celiac disease based on common assays, who actually meet the criteria for non-biopsy diagnoses based on the European standard.

In an interview with HCPLive during the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) 2023 Annual Meeting in San Diego this week, study author Denis Chang, MD, discussed the trial’s design in relation to the current standard for celiac disease diagnostics in North America.

“The gold standard for making the diagnosis is to have an endoscopy, whereas we get biopsies to confirm whether or not the damage that we anticipate to be there, to be there with someone that's on a gluten-containing diet,” Chang explained. “Serology has really been a game changer because it helps us to screen who is it that needs to go on to have an endoscopy based on a positive blood test, the most positive most common blood has been a tissue transglutaminase (tTG-IgA).”

While tTG-IgA is a reliable biomarker, it is not perfect, Chang said—false positives or negatives are possible.

“Back in 2012, our European colleagues created guidelines where you can make the diagnosis of celiac disease in kids in some cases where you have a really highly positive tTG IgA along with another positive blood marker, EMA IgA,” Chang said. “Back then, they also included some other aspects such as genetic risk and symptoms, but that's no longer the case.”

Meanwhile, North American colleagues have not adopted such a guideline. One reason for this is due to litany of varying assays used to diagnose celiac disease, despite there being different methodologies for each..

“And then there’s always a concern that we might be missing other potential diagnoses by not doing an endoscopy, such as eosinophilic esophagitis, which we can see in a lot of our celiac patients,” Chang said. “In an ideal world, we'll have just one assay, we know how good that one assay is, and that's the one that everyone uses, so we would know in that setting if it's highly positive or it meets this threshold, maybe we can make a diagnosis based on that blood marker alone.”

Designing and standardizing a nationally-utilized assay strategy may also pay dividends in clinical therapy development. There are currently no drugs approved by the US Food and Drug Administration (FDA) for the treatment of celiac disease—and the most promising agents in development are intended for adult patients, Chang said.

“Being able to say that there's another way that we can make a diagnosis—especially if endoscopy is not something that is something that everyone's agreeable to, or there's other complicating factors—then it could potentially increase that pool of individuals that can work together in the celiac community as providers and patients to work towards another treatment,” Chang said. “(It could also provide) clarity as well, because a lot of people come in with a diagnosis of presumed celiac disease because they've never had a biopsy. They've only had really high blood markers.”

Reference

^{Chang D, Wong M, Cardenas MC, Raber C, et al. Assessing Serologic Thresholds Using Common North American Assays to Diagnosed Celiac Disease: A Multicenter Retrospective Study. Paper presented at: North American Society for Pediatric Gastroenterology, Hepatology and Nutrition 2023 Annual Meeting; October 4 - 7; San Diego, CA. Accessed October 5, 2023.}