PTH-065 Single centre experience of simtomax, a point-of-care test for coeliac disease, to avoid duodenal biopsies

Abstract

Introduction The British Society of Gastroenterology (BSG) guidelines recommend screening for coeliac disease in patients with iron deficiency anaemia (IDA) with coeliac serology; but states that if it hasn’t been carried out or if the result is unavailable, duodenal biopsies should be taken if the patient is undergoing a gastroscopy. As the prevalence of coeliac disease in the UK is around 1% and 5% in IDA, majority of duodenal biopsies are negative. As biopsies are costly we have been investigating ways to avoid doing them without missing the diagnosis of coeliac disease. Simtomax is a finger prick test for coeliac disease that provides immediate results, hence shown to be valuable as a negative predictive test.1 The aim was to evaluate the value of Simtomax pre-endoscopy to reduce the number of duodenal biopsies without missing the diagnosis of coeliac disease in our local population. Methods Between May-December 2016 we obtained informed consent and performed 106 Simtomax tests on patients attending for a gastroscopy (OGD) with an indication of anaemia/weight loss prior to their endoscopy. Using our databases, we collected the following: patient demographics, coeliac serology (anti tTG/EMA) if done, OGD findings and duodenal biopsy histology. Results 106 patients (M=38, mean age 62, age range 34–91; F=68, mean age 62, age range 18–95) had both a Simtomax test and an OGD. 101/106 had duodenal biopsies (endoscopist’s discretion) and 52 (49%) had coeliac serology (anti tTG). With histology as the gold standard for the diagnosis of coeliac disease, prevalence of the disease in these patients with IDA/weight loss was 3%. The negative predictive value (NPV) of a negative Simtomax test was 96% and the NPV of a negative Simtomax AND negative coeliac serology was 97%. The positive predictive values were 11% and 33% respectively for these 2 tests. The sensitivity and specificity of Simtomax were 33% and 96%. Conclusions In the current NHS climate every saving is welcome as long as patient care isn’t compromised. Our study shows that around 50% of patients attending for an OGD for IDA/weight loss didn’t have coeliac serology available at the time of the procedure, therefore requiring duodenal biopsies as per BSG guidelines. Using a point of care test with a high negative predictive value would save more patients from having biopsies, save money1 and valuable time of endoscopists, nurses and histopathologists. Our study confirms the high NPV of the point of care test Simtomax and would save biopsies in 96% of patients who haven’t had coeliac serology prior to endoscopy (a saving of around £100 per set of duodenal biopsies). Reference 1. BMC Gastroenterol. doi:10.1186/s12876–016–0521537