P0391 DIET COMPLIANCE EVALUATION OF COELIAC PATIENTS IN POINT-OF-CARE FASHION

Abstract

Introduction: Circulating IgA antibodies against endomysium (EMA) and transglutaminase 2 (TG2) are activity markers of coeliac disease and their regular measurement is important in the diet surveillance and consueling of treated coeliac patients. In this study we investigated whether significant dietary transgressions could be detected onsite in the outpatient department and whether the prompt availability of results would promote the improvement of the compliance. Methods: 257 patients (aged 2.2–76 years, median 13) with previously diagnosed coeliac disease and on diet for 1 month-12 years were evaluated in a point-of-care fashion in two paediatric gastroenterology departments in connection with independently scheduled check-up visits that included laboratory measurements of serum EMA and anti-TG2 antibodies. Diet compliance was estimated by a questionnaire and an interview. Nine of the patients were IgA deficient. The point-of-care testing was performed from one drop of whole blood with a recently developed rapid stick test which utilises the patients’ own red blood cell TG2 for the detection of IgA class plasma antibodies against TG2 and does not require a purified TG2 antigen. The test also has a positive control line for plasma IgA detection to sort out IgA deficient samples. The rapid test has been previously validated in untreated patients undergoing jejunal biopsy where it showed 97.5% sensivity and 96% specificity. Serum EMA was assayed on monkey oesophagus in 1:2.5 dilutions and anti-TG2 by ELISA with human recombinant TG2. Results: The rapid test was positive in 53 (20.6%), EMA in 52 (20.3%) and TG2-ELISA in 45 (17.5%) of the patients. Agreement in all three tests was seen in 90.6% of samples. The rapid test results were in agreement with EMA in 94.9 % and with TG2-ELISA results in 91.4% of the samples whereas EMA and TG2-ELISA results were congruent in 94.9% of samples. The rapid test correctly identified IgA deficient subjects. The antibody tests detected more dietary lapses than estimated by the clinical interview. Positive rapid test results were discussed with the patients. The rapid test was repeated after 2–6 months in 14 patients with positive results and it came out as negative in 12/14 after diet correction. Conclusion: The performance of the rapid test was as good as those of laboratory tests in detecting disease activity. Point-of-care coeliac antibody testing is a convenient, economical and easy tool in the care of coeliac patients which promotes diet compliance.