By Amy Ratner, Medical and Science News Analyst

A celiac disease diagnosis should include a biopsy, in which small samples are taken from the intestine and sent to a pathologist for review.

But if you are facing this procedure or have already had it done, it’s possible you didn’t know exactly how the samples are gathered and then interpreted by the healthcare professionals involved in the process.

And you would not be alone. Sometimes even the gastroenterologist who takes the samples, the pathologist who looks at them under a microscope and the doctor who uses the results to make a diagnosis need to be reminded of the steps that result in the best care for patients.

Kendall Egan, of Rye, N.Y., was diagnosed with celiac disease 20 years ago by an internist who told her after an endoscopy and biopsy that the results provided clear evidence she had a malabsorption syndrome.

“I had no idea what they were looking for. I did not know what they did,” Egan said. “I was in recovery when the doctor came in and said you definitely have celiac disease.”

Egan said she had much better understanding of the procedure when she subsequently went to the Celiac Disease Center at Columbia University, where the biopsy was repeated. Her physician explained that he was looking for flattened villi and would take small samples of her intestine. “It was the difference between going to a celiac center versus the gastroenterologist,” Egan said, noting that she hopes things have improved in the years since she had the procedure, particularly when the biopsy is done somewhere other than a celiac center.

A new celiac disease research study in published in the American Journal of Surgical Pathology attempts to improve biopsy diagnosis by describing the best practices in the use of the endoscopy and biopsy for patients with suspected celiac disease. The study lays out workable guidelines that can be used in daily practice.

Best practices

Marie Robert, M.D., a surgical pathologist at Yale University School of Medicine and chief scientific officer for Beyond Celiac, is the lead author of the study.

Learn more: Marie Robert talks about her new role on facebook live

She and colleagues conducted a review of the literature addressing endoscopy and biopsy for celiac disease and compiled data to create the best practice recommendations.

The study recommends that:

• Endoscopists always do a biopsy even in cases where the intestine looks normal during the endoscopy, since the lining may appear to be normal even in patients with celiac disease.

Duodenum: The first and shortest part of the small intestine

• Endoscopists take at least two samples from the first part of the duodenum, just past the stomach, and at least four samples further down the length of the duodenum (called the second part of the duodenum).
• Physicians provide pathologists with information regarding the potential for celiac disease, including symptoms, medications taken by the patient, patient and family medical history, status of the gluten-free diet and blood and genetic test results.

Intraepithelial lymphocytes: White blood cells found in the lining of the small intestine

• Pathologists provide physicians with information regarding intraepithelial lymphocytes, as the evaluation of their number and location can be useful in celiac disease diagnosis, particularly when the biopsy otherwise appears to be normal.
• Pathologists always describe the damage to the intestinal villi when there is a suspicion of celiac disease. The villi can be described as normal, partially flattened, or completely flattened; or rated according to a classification system such as the Marsh classification. A comparison to any previous biopsies is also be helpful.
• Pathologists and physicians avoid over- and under-diagnosis of celiac disease by being aware of the variety of causes of inflammatory changes seen in biopsies and correlating biopsy findings with patient demographics, symptoms, infections and blood and genetic tests. Medication history can be especially important because some cause injury to the intestine similar to that caused by celiac disease. Olmesartan, a drug used to treat high blood pressure, as well as NSAIDs and some checkpoint and kinase inhibitors used to kill tumor cells, are among the drugs that can cause this reaction.

“The diagnosis of celiac disease requires close cooperation between clinical, endoscopic and laboratory practices,” the study concludes. Informed dialogue between the specialties is crucial.”

Learn more: How celiac disease is diagnosed

Takeaways for patients

The study is intended to help clinicians and pathologists with the finer points of diagnosis, the authors note. But there are also cealiac disease research takeaways for patients, both before and after the procedure.

“Patients undergoing an upper endoscopic examination in order to consider a diagnosis of celiac disease should verify up front with their gastroenterologist both the number and location of biopsies to be taken,” Robert said. “This is important since the biopsy changes in celiac disease may be patchy and could be missed if the appropriate number of biopsies is not obtained.”

After the endoscopy and biopsy are done, patients should receive a copy of the pathologist’s report.

“The biopsy report should either specify that the biopsy is normal, or, if abnormal, should discuss the villi and presence or absence of inflammation, such as intraepitheial lymphocytes,” Robert explained. “Patients having questions about the pathology report should start by asking their gastroenterologist for clarification. They may also request to speak to the pathologist for more information if questions remain.”

You can find the study here.