Coeliac Screening Test

What is Coeliac Disease?

Coeliac disease (CD) is a disease that damages the small intestine and interferes with absorption of nutrients from food. People who have CD cannot tolerate gluten, a protein in wheat, rye, and barley. Gluten is found mainly in foods but may also be found in everyday products such as medicines, vitamins, and lip balms.

When people with CD eat foods or use products containing gluten, their immune system responds by damaging or destroying villiâe the tiny, fingerlike protrusions lining the small intestine. Villi normally allow nutrients from food to be absorbed through the walls of the small intestine into the bloodstream. Without healthy villi, a person becomes malnourished, no matter how much food one eats. CD is a life-long disease and affects around 1 in 100 people in the UK. The disease can affect anyone at any age but a definite risk factor is a family history of CD as it is a genetic condition. The only treatment for CD is a gluten-free diet.

Symptoms of Coeliac disease:
Weight loss
Tiredness
Lethagy
Vomiting
Breathlessness
Abdominal discomfort, pain and bloating
Mouth ulcers
Diarrhoea
Anaemia (most commonly Fe or folate, but also B12)
Dermatitis herpetiformis
Osteoporosis
Depression
Muscle weakness
Bone pain
Infertility and recurrent miscarriage
Amenorrhea

Because of the broad range of symptoms, CD is difficult to diagnose. If undiagnosed, CD patients who continue to ingest gluten will have an increased risk of developing gastrointestinal tumours, making early detection of CD very important.

Testing for Coeliac disease
While an intestinal biopsy is the gold standard for diagnosing CD, there are now blood tests available to screen for CD. Testing is simple and involves either screening a pin-prick sample of blood for Gliadin IgA and Gliadin IgG antibodies or Tissue transglutaminase IgA antibodies.

How do the tests work?
Gliaidn IgA and Gliadin IgG test
Gliadin is a major protein found in the gluten fraction of wheat. Antibodies to gliadin are found in approximately 95% of untreated CD patients i.e patients are not on a gluten-free diet. Gliadin IgA antibodies are highly specific for CD and occur in approximately 80% of patients. Gliadin IgG antibodies are also associated with CD but are less specific for the disease as they also occur in a number of other conditions. However, as patients with CD can exhibit IgA deficiency, which gives rise to false negative gliadin IgA results.

Transglutaminase IgA test
Recent studies have shown that IgA antibodies to tissue transglutaminase (tTG), an enzyme present in the connective tissue of the gut, are also strongly associated with the presence of CD. tTG IgA antibodies are both highly sensitive (95% -100%) and specific (90%-97%) for CD. As with gliadin IgA, if a patient is IgA deficient, the IgA test may be falsely negative; in such cases the gliadin IgG test is recommend

Sample requirements &, test turnaround
A pin-prick blood sample is required. Results are available within 10 working days.