IBD: Fecal Calprotectin's Role in Guiding Treatment Debated

Marcia Frellick

December 10, 2020

Questions on fecal calprotectin's usefulness as a measure of intestinal inflammation in inflammatory bowel disease (IBD) dominated the viewer chat after the opening session of Advances in Inflammatory Bowel Diseases 2020 Annual Meeting on Wednesday.

The measure is often used to differentiate irritable bowel syndrome (IBS) from IBD.

Panelists differed on how predictive fecal calprotectin is for disease status and what information the stool concentration of calprotectin imparts. Several experts discussed calprotectin cutoffs for when disease would be considered in remission or when a colonoscopy is needed for evaluation.

Bruce E. Sands, MD, from the Icahn School of Medicine at Mount Sinai in New York City, said about the noninvasive test, "It can be very tricky to use."

Variation by Time of Day, by Person

He explained that there can be individual differences, and that the concentration may be different in the first stool of the day compared with the last.

"There's a lot of variation, which makes the cutoffs good on average for populations but a little bit more difficult to apply to individuals," he said.

Sands said the marker has more merit for people with large-bowel inflammation but is not quite as accurate a marker for patients with exclusively small-bowel inflammation.

Moderator Steven Hanauer, MD, professor of medicine, gastroenterology and hepatology at the Feinberg School of Medicine at Northwestern University in Chicago, asked Sands what his next move would be if a patient had a concentration of 160 μg/mg.

Sands called concentrations between 150 and 250 μg/mg "a gray zone."

"That usually indicates for me a need to evaluate with a colonoscopy," he said.

"If we're talking about using fecal calprotectin to rule out IBS, the cutoff there is more like 50, 55. But that isn't how we're generally using it as IBD practitioners."

Sunanda V. Kane, MD, MSPH, a gastroenterologist with the Mayo Clinic in Rochester, Minnesota, told Medscape Medical News that 160 μg/mg in a patient with IBD "means to me likely some minimal disease but not enough for me to make drastic changes to a medical regimen."

She said about the measure, "We need to understand its limitations as well as strengths. Right now, insurance companies consider it "experimental" and a lot of companies will not cover it. Ironically, they will cover the cost of a colonoscopy but not a stool test."

Use as a Benchmark

Sands said if he's doing a colonoscopy to establish that the patient is in remission and knows what the fecal calprotectin level is at the time, he uses it as a benchmark for the future to judge whether the patient is deviating from remission.

He added that the negative predictive value of fecal calprotectin with a cutoff of 100 μg/mg is "actually pretty good so you can avoid a number of unnecessary colonoscopies to look for recurrence."

William J. Sandborn, MD, from the University of California, San Diego, said about the marker, "We use it some, but a cutoff of 50 is very specific. You can think of that as equivalent to a Mayo endoscopy score of 0 in ulcerative colitis and probably histologic remission."

Cutoffs above 50 μg/mg are "not very clear," he said.

He said given the lack of consensus on the panel, "others might take some pause about that discomfort."

Sandborn pointed out that little is known about elevated calprotectin in ulcerative proctitis and whether it is elevated in Crohn's ileitis.

Kane said other factors will affect fecal calprotectin levels.

"We have some data to say that if you are on a proton pump inhibitor that that changes fecal calprotectin levels. Patients who have inflamed pseudopolyps may have quiescent disease around the pseudopolyps that may elevate the fecal calprotectin."

But it can have particular benefit in some patient populations, she said.

She pointed to a study that concluded calprotectin levels can be used in pregnant ulcerative colitis patients to gauge disease activity noninvasively.

Sands, Sandborn, Kane, and Hanauer  have disclosed no relevant financial relationships.

Advances in Inflammatory Bowel Diseases (AIBD) 2020 Annual Meeting: Session I. Presented December 9, 2020.

Marcia Frellick is a freelance journalist based in Chicago . She has previously written for the Chicago Tribune, Science News and Nurse.com and was an editor at the Chicago Sun-Times, the Cincinnati Enquirer, and the St. Cloud ( Minnesota ) Times. Follow her on Twitter at @mfrellick

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