Introduction Chromoendoscopy is increasingly being used to detect, localise and characterise mucosal abnormalities, however its role in coeliac disease remains to be established. Endoscopic markers of coeliac disease (reduction of folds, scalloping, mosaic pattern, visible blood vessels and nodularity of the duodenal folds) are often difficult to recognise, therefore many centres take routine duodenal biopsies or have a low threshold for biopsy, ensuring high detection rates. This study evaluates if dye spray can improve identification of endoscopic markers of coeliac disease, potentially leading to a biopsy avoidance strategy.

Methods Patients undergoing clinically indicated oesophogastroduodenoscopy (OGD) were prospectively recruited from a single endoscopy list between January 2011 and November 2012. Patients were divided into two groups: patients with no previous history of coeliac disease (Group 1, n = 201) and patients with established coeliac disease (Group 2, n = 24). Eight experienced endoscopists undertook all procedures, with endoscopic findings reported both before and after the use of indigo carmine dye spray. Endoscopic findings were compared using a McNemar test, with p values < 0.05 considered significant. In addition, endoscopic findings were compared to histological findings to determine sensitivity, specificity, positive predictive values (PPV) and negative predictive values (NPV) for differing endoscopic techniques.

Results Of the 225 patients recruited, 97 (43%) had positive serology (either endomysial or tissue transglutaminase antibodies). In Group 1, 61(30%) were newly diagnosed coeliac patients with endoscopic markers identified in 44% (27/61). Dye spray use within the duodenum identified a further 5 patients (32/61, 52%), however this improvement in diagnostic yield was not statistically significant (P = 0.63). Sensitivity, specificity, positive and negative predictive values for standard endoscopy to detect coeliac disease were 44%, 99%, 93%, 80% respectively compared to 52%, 99%, 94%, 83% for chromoendoscopy. In Group 2, 12 patients had persisting Marsh 3 changes at biopsy, however endoscopic markers were identified in only 5 (21%) with dye only increasing yield by a further one patient (6/24, 25%).

Conclusion Dye spray is easy to use and inexpensive (<£1/endoscopy), however in our study derived no additional benefit to conventional endoscopy for diagnosing patients with coeliac disease. Given the low sensitivity of endoscopic markers, we advocate duodenal biopsies in all patients where there is a high clinical suspicion of coeliac disease, irrespective of the endoscopic mucosal findings.

Disclosure of Interest None Declared