Suppose the biopsy or serum tests are inconclusive. What do you do?**

Vijay Kumar, M.D., Research Associate Professor at the University of Buffalo and President and Director of IMMCO Diagnostics: The biopsy may be inconclusive. Serum, if tested for gliadin, endomysial and reticulin antibodies, should provide unequivocal information. Ours and other studies have provided a strong reliability of the serum tests.

Karoly Horvath, M.D., Ph.D., Associate Professor of Pediatrics; Director, Peds GI & Nutrition Laboratory; University of Maryland at Baltimore: The biopsy may be inconclusive in a small percentage of patients with so-called patchy lesions in the duodenum. It means that there are histologically normal looking spots with finger like villi and pathologic spots showing flattened mucosa in the upper half of the duodenum. If celiac disease is suspected, the gastroenterologist should obtain several biopsies from different spots of the whole duodenum. Most of the endoscopists routinely examine only the upper half of the duodenum (duodenal bulb and the descending part). The transverse segment of the duodenum is not viewed routinely. Few endoscopic centers have an enteroscope, which is a longer and more flexible endoscope for examining the entire duodenum and jejunum. The enteroscopy allows you to obtain biopsies even from the jejunum. The histological examination of a single biopsy specimen may increases the risk of false negative diagnosis.

Celiac.com Sponsor (A12):
The experience of the pathologist in the interpretation of small intestinal histology is important. In centers specializing in celiac disease the gastroenterologist routinely reviews the histologic slides together with the pathologist. There is still a possibility of inconclusive results if multiple biopsies are obtained and the histological interpretation is appropriate. All disease has a developmental process. It means that it takes time for the pathological changes to be evident. There are cases when the symptoms suggest celiac disease, however, the histology is not conclusive. This problem occurs in only a few cases. A repeated biopsy may be necessary after a period of higher gluten intake. However, if the antiendomysium antibody test is positive and the histology is not conclusive a gluten-free diet is recommended.

The serology test may be inconclusive if:

• The sample handling and shipping is inappropriate; e.g. the serum was shipped at room temperature for days
• The patient has IgA deficiency, which occurs in one out of 600 people in the general population and much more frequently in patients with celiac disease. In these cases the antigliadin IgA and the antiendomysium IgA tests give negative results. If the tests are performed in a laboratory specialized in celiac serological tests, the laboratory recommends a test for immunoglobulins. If a patient has IgA deficiency and positive antigliadin IgG test, he/she should undergo further absorptive tests and/or an intestinal biopsy.