Testing for Celiac Disease

Testing for Celiac Disease 

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Testing is based on antibody tests and small intestine duodenal biopsies. A person with coeliac disease produces antibodies to gluten when eaten, which can be measured. As coeliac disease is an important medical condition, with lifelong implications, getting a definite diagnosis is essential.

It is very important NOT to stop eating gluten during the tests, even if positive (you are likely to require a biopsy) – this is extremely important.

Adults

First choice test:

  • Total IgA  and IgA tissue transglutaminase (tTG)
  • Use IgA endomysial antibodies (EMA) if IgA tTG is weakly positive
  • Consider IgG EMA, IgG deaminated gliadin peptide (DGP) or IgG tTG if IgA is deficient

Children

  • Total IgA and IgA tTG as the first choice
  • Consider IgG EMA, IgG deaminated gliadin peptide (DGP) or IgG tTG if IgA is deficient
  • For children a biopsy may not be required in every case. If the child is symptomatic on eating gluten; IgA tTG level ten times normal; EMA positive on a different blood sample. HLA-DQ2/DQ8 positive (ESPHGAN).

Points to Note

  • IgA tTG is the most sensitive and specific blood test.
  • IgA deficiency is more common in people with coeliac disease, if deficient this could lead to a false negative result when testing for IgA tTG
  • Gluten should be eaten at least once a day for 6 weeks prior to testing
  • Genetics: In order to develop coeliac disease HLA (human leukocyte antigen) DQ2/DQ8 genes must be present. Testing can be useful to rule out coeliac disease where diagnosis is uncertain. Testing negative makes coeliac  disease very unlikely. However, testing positive for HLA DQ2/DQ8 cannot be used to diagnose coeliac disease as the genes are found in up to 40% of people, yet only a small percentage go on to develop coeliac disease.
  • Ethnicity should not be used to rule out celiac disease.  Studies show that celiac disease is possible in Asian and South East Asian heritage.

Laboratories:

Tan Tock Seng

References:

Coeliac disease: recognition, assessment and management. National Institute for Health and Care Excellence; September 2015

Diagnosis and Management of adult coeliac disease: Guidelines from the British Society of Gastroenterology 2014 (panel from 8 countries)

ESPHGAN (European Society for Paediatric Gastroenterology, Hepatology & Nutrition) Guidelines 2012

www.beyondceliac.org

www.coeliac.org.au

www.coeliac.org.uk

2018-08-04T23:49:38+00:00