Dr Tim Stokes (left) and Professor Peter Howdle explain the importance of offering serological testing to patients with suspected coeliac disease in line with NICE guidance
Coeliac disease is a state of heightened immunological response to ingested gluten (a protein present in wheat, barley, and rye) in genetically susceptible people.1 Treatment with a gluten-free diet is very effective for managing this condition. Coeliac disease has conventionally been associated with mainly gastrointestinal symptoms (such as diarrhoea, abdominal pain, bloating, constipation, and indigestion) because chronic inflammation of the small intestine is a characteristic of the immune response to gluten. Coeliac disease is, however, associated with a wide range of non-gastrointestinal symptoms, including anaemia and prolonged fatigue. Moreover, some people with coeliac disease have no obvious symptoms.1
Coeliac disease is common in both children and adults, with an estimated prevalence in the UK of between 0.8% and 1.9%. Among first-degree relatives of people with the disease, the prevalence is higher: between 4.5% and 12%.1 Coeliac disease is also more prevalent in people with autoimmune conditions such as type 1 diabetes.1
However, because of the disparate nature of its signs and symptoms, and the historical belief that it is not a common condition, there is concern that coeliac disease often remains unrecognised and consequently is underdiagnosed. It is actually estimated that only 10%–15% of people are clinically diagnosed with it.1,2 Therefore, patients may be presenting to primary and secondary care on a number of occasions and with a range of symptoms before diagnosis.
Delayed diagnosis of coeliac disease is a concern because untreated and undiagnosed symptoms can lead to complications, such as growth failure (children) and osteoporosis (adults).1
The NICE guideline on Recognition and assessment of coeliac disease has been published to improve the care of children and adults with undiagnosed coeliac disease in generalist settings.1 It provides evidence-based recommendations on recognising coeliac disease, including the appropriate use of serological testing to identify patients who need referral to a gastroenterologist for a definitive diagnosis through intestinal biopsy.1 As most undiagnosed cases of the condition will present in general practice, the GP and other members of the primary healthcare team have a crucial role in identifying children and adults who should be tested for coeliac disease.3
Who should be offered serological testing?
Patients with symptoms, signs, and co-existing conditions (as shown in Box 1) should be offered serological testing as these are sufficiently associated with coeliac disease. For a wider range of symptoms, signs, and coexisting conditions there is some evidence that these are associated with coeliac disease. General practitioners therefore need to have an index of suspicion for coeliac disease when seeing such patients and should consider offering testing for coeliac disease as appropriate (see Box 1).
|Box 1: Who should be tested for coeliac disease?1|
Offer testing to children and adults with any of the following signs and symptoms or conditions:
|Consider offering testing to children or adults with any of the following:
|Figure 1: Serological testing in children and adults with suspected coeliac disease seen in primary care1|
|*Investigation for IgA deficiency should be done if the laboratory detects a low or very low optical density on IgA tTGA test or low background on IgA EMA test
IgA=immunoglobulin A; tTGA=tissue transglutaminase; EMA=endomysial antibodies; IgG=immunoglobulin G
National Institute for Health and Care Excellence (NICE) (2009) CG86. Coeliac disease: recognition and assessment of coeliac disease. London: NICE. Reproduced with permission. Available from www.nice.org.uk/CG86
Advice to patients
It is vital that patients receive appropriate advice relating to the recognition and assessment of coeliac disease:1
- Inform patients that testing for coeliac disease is accurate only if the person is following a diet that contains gluten at the time of testing:
- when following a normal gluten-containing diet the patient should eat some gluten (for example, bread, pasta, biscuits, or cakes) in more than one meal everyday for a minimum of 6 weeks before testing
- If a patient is reluctant or unable to reintroduce gluten into their diet before testing, refer them to a gastrointestinal specialist and inform them that it may be difficult to confirm a diagnosis of coeliac disease on an intestinal biopsy
- Inform patients and their parents or carers that a delayed diagnosis of coeliac disease or undiagnosed coeliac disease, can result in:
- continuing ill health
- long-term complications, including osteoporosis and increased risk of fracture, unfavourable pregnancy outcomes, and a modest increased risk of intestinal malignancy
- growth failure, delayed puberty, and dental problems in children.
In primary care, children and adults with symptoms and signs that are suggestive of coeliac disease should be offered serological testing. General practitioners need to know what to do if a patient has a positive test result and also what to do if coeliac disease is clinically suspected but serology results are negative (see Figure 1). The NICE Guideline Development Group reviewed the clinical evidence in this area, while also considering the cost effectiveness of serological tests by developing a new health economic model.1 Serological testing should be performed in accordance with the following points:1
- All tests should be undertaken in laboratories with clinical pathology accreditation (CPA)
- Do not use immunoglobulin G (IgG) or immunoglobulin A (IgA) anti-gliadin antibody (AGA) tests in the diagnosis of coeliac disease
- Do not use self-tests and/or point-of-care tests for coeliac disease as a substitute for laboratory based testing.
- When clinicians request serology, laboratories should:
- use IgA tissue transglutaminase (tTGA) as the first choice test
- use IgA endomysial antibody (EMA) testing if the result of the tTGA test is equivocal
- check for IgA deficiency if the serology is negative
- use IgG tTGA and/or IgG EMA serological tests for people with confirmed IgA deficiency
- communicate the results clearly in terms of values, interpretation, and recommended action
- Investigation for IgA deficiency should be done if the laboratory detects a low or very low optical density on IgA tTGA test or low background on IgA EMA test
- Do not use human leukocyte antigen (HLA) DQ2/DQ8 testing in the initial diagnosis of coeliac disease (however, its high negative predictive value may be of use to gastrointestinal specialists in specific clinical situations).
After serological testing:1
- offer referral to a gastrointestinal specialist for an intestinal biopsy to confirm or exclude coeliac disease in people with positive serological results from any tTGA or EMA tests
- if serology tests are negative but coeliac disease is still clinically suspected, offer referral to a gastrointestinal specialist for further assessment.
Although there will be higher costs to the NHS in the short term because of an increase in testing, in the long run appropriate treatment of previously undiagnosed cases will reduce a range of NHS costs.4
Coeliac disease is a common condition that is underdiagnosed in both children and adults. The NICE guideline emphasises the variety of symptoms and signs that can arise from coeliac disease and the many conditions that may co-exist with it. The guidance aims to raise awareness of coeliac disease and increase the appropriate use of the serological tests needed to make a presumptive diagnosis, thus enabling effective treatment and improvement of the health and quality of life of people with the condition.
Further sources of information
Additional information on coeliac disease can be found from the following sources:
- National Institute for Health and Care Excellence. Coeliac disease: recognition and assessment of coeliac disease (CG86). Quick Reference Guide. London: NICE, 2009. Available at: www.nice.org.uk/guidance/CG86/QuickRefGuide/pdf/English
- National Institute for Health and Care Excellence. Coeliac disease: recognition and assessment of coeliac disease. Understanding NICE guidance. London: NICE, 2009. Available at: www.nice.org.uk/guidance/CG86/PublicInfo/pdf/English
- Howdle P. Your guide to coeliac disease. London: Hodder Arnold, 2007.
- Coeliac UK—the leading charity working for people with coeliac disease and dermatitis herpetiformis. The website offers detailed advice on all aspects of coeliac disease
|NICE implementation tools|
NICE has developed the following tools to support implementation of its guideline on Coeliac disease: recognition and assessment of coeliac disease. They are now available to download from the NICE website: www.nice.org.uk
National cost reports and local cost templates for the guideline have been produced:
The slides are aimed at supporting organisations to raise awareness of the guideline and resulting implementation issues at a local level, and can be edited to cater for local audiences. This information does not supersede or replace the guidance itself.
Audit support has been developed to support the implementation of the NICE guideline on coeliac disease. The aim is to help NHS organisations with a baseline assessment and to assist with the audit process, thereby helping to ensure that practice is in line with the NICE recommendations. The audit support is based on the key recommendations of the guidance and includes criteria and data collection tools.
- The care pathway in the NICE guideline is ideal for local adaptation
- PBC consortia should explore whether specialist assessment and endoscopy can be undertaken in the community to avoid full tariff cost
- This role would be very suitable for an appropriately trained GPwSI
- Consideration should be given to commissioning a dietetic service to support patients who are newly diagnosed with coeliac disease and avoid specialist follow up
- Increased diagnosis will increase prescribing expenditure on gluten-free products—a local formulary may help here
- Traffic costs:a
- endoscopy = £406 (planned same day)
- gastroenterology outpatient = £158 (new), £79 (follow up)
- National Institute for Health and Care Excellence. Coeliac disease: recognition and assessment of coeliac disease. Clinical Guideline 86. London: NICE, 2009. Available at: www.nice.org.uk/Guidance/CG86
- Van Heel D, West J. Recent advances in coeliac disease. Gut 2006; 55 (7): 1037–1046.
- Jones R. Coeliac disease in primary care. BMJ 2007; 334 (7596): 704–705.
- National Institute for Health and Care Excellence. Coeliac disease: Costing report. Implementing NICE guidance. London: NICE, 2009. Available at: www.nice.org.uk/nicemedia/pdf/CG86CostReport.pdf G