The role of a point of care test for the diagnosis and management of coeliac disease.

Coeliac disease is a systemic autoimmune disease associated with gastrointestinal and extra-gastrointestinal symptoms, triggered by gluten in genetically susceptible individuals. It affects 1% of the general population (1, 2), although 75% remain undiagnosed (3). Delayed diagnosis can lead to a poor quality of life and complications (3). The under-detection could be due to non-specific symptoms and under-utilisation of serological testing (4). Several point of care tests for coeliac disease have been developed in the past decade, which may potentially help to improve case detection. A few recent studies have shown that Simtomax, a point of care test detecting IgA-/IgG-deamidated gliadin peptide antibodies (IgA/IgG-DGP), appeared to have comparable sensitivities to conventional serology. However, further studies are required to validate the diagnostic performance of Simtomax. The null hypothesis of my thesis is that a point of care test has no role in the diagnosis and management of coeliac disease. We aimed to evaluate the sensitivities, utility and cost effectiveness of the point of care test, Simtomax, in various domains: Study 1: To assess the role of Simtomax as a primary care case finding tool for coeliac disease in high risk individuals in community pharmacies. Study 2: To demonstrate the diagnostic accuracy of Simtomax in secondary care, in patients referred with gastrointestinal symptoms or self-reported gluten sensitivity. Study 3: To establish the diagnostic accuracy of Simtomax and its cost effectiveness of coeliac testing in patients with iron deficiency anaemia in the endoscopy setting. Study 4: To investigate whether Simtomax is a reliable surrogate marker for predicting histological remission in patients with known coeliac disease on a gluten free diet