This guideline presents recommendations for the management of coeliac disease (CD) and other gluten-related disorders both in adults and children.
There has been a substantial increase in the prevalence of CD over the last 50 years and many patients remain undiagnosed. Diagnostic testing, including serology and biopsy should be performed on a glutencontaining diet.
The diagnosis of CD is based on a combination of clinical, serological and histopathological data. In a group of children the diagnosis may be made without biopsy if strict criteria are available.
The treatment for CD is primarily a gluten-free diet (GFD), which requires significant patient education, motivation, and follow-up. Slow-responsiveness occurs frequently, particularly in those diagnosed in  adulthood.
Persistent or recurring symptoms necessitate a review of the original diagnosis, exclude alternative diagnoses, confirm dietary adherence (dietary review and serology) and follow-up biopsy. In addition, evaluation to exclude complications of CD, such as refractory CD or lymphoma, should be performed. The guideline also deals with other gluten-related disorders, such as dermatitis herpetiformis, which is a cutaneous manifestation of CD characterized by granular IgA deposits in the dermal papillae. The skin lesions clear with gluten withdrawal. Also, less well-defined conditions such as non-coeliac gluten sensitivity (NCGS) and gluten-sensitive neurological manifestation, such as ataxia and have been addressed.
Newer therapeutic modalities for CD are being studied in clinical trials, but are not yet approved for use in practice.

Keywords: Coeliac disease; seronegative coeliac disease; dermatitis herpetiformis; non-coeliac gluten sensitivity; gluten ataxia; neurocoeliac; coeliac neuropathy; slow-responder coeliac; refractory coeliac disease; enteropathy associated T-cell lymphoma

Introduction

13C-breath tests are valuable, noninvasive diagnostic tests that can be widely applied for the assessment of gastroenterological symptoms and diseases. Currently, the potential of these tests is compromised by a lack of standardization regarding performance and interpretation among expert centers.

Methods

This consensus-based clinical practice guideline defines the clinical indications, performance, and interpretation of 13C-breath tests in adult and pediatric patients. A balance between scientific evidence and clinical experience was achieved by a Delphi consensus that involved 43 experts from 18 European countries. Consensus on individual statements and recommendations was established if >= 80% of reviewers agreed and <10% disagreed.

Results

The guideline gives an overview over general methodology of 13C-breath testing and provides recommendations for the use of 13C-breath tests to diagnose Helicobacter pylori infection, measure gastric emptying time, and monitor pancreatic exocrine and liver function in adult and pediatric patients. Other potential applications of 13C-breath testing are summarized briefly. The recommendations specifically detail when and how individual 13C-breath tests should be performed including examples for well-established test protocols, patient preparation, and reporting of test results.

Conclusion

This clinical practice guideline should improve pan-European harmonization of diagnostic approaches to symptoms and disorders, which are very common in specialist and primary care gastroenterology practice, both in adult and pediatric patients. In addition, this guideline identifies areas of future clinical research involving the use of 13C-breath tests.

Keywords: breath test, diagnosis, gastroenterology, gastroparesis, helicobacter pylori, liver cirrhosis, motility, pancreatic exocrine insufficiency, pancreatitis