The disease where the body can´t absorb any gluten in food, and if eating accidentally too much of it, it causes diarea, blisters on the skin and up to 20% higher risk of cancer in various parts of the body. It can brake out any time of life and is NOT listed as an allergy, but as a genetic disease.
Diagnosis
Tests
The gold standard test for coeliac disease is still upper endoscopy with biopsy of the distal duodenum or jejunum. To avoid false negative results, the first endoscopy must be done while the patient is on a normal, gluten-containing diet or very shortly after going on a gluten-free diet. Sometimes the endoscopy is repeated after the patient has been on a gluten-free diet, in order to ensure that the bowel has healed. However, upper endoscopy always carries a risk of false negative results. This is because coeliac disease may or may not damage villi throughout the entire small intestine, and upper endoscopy only examines the upper part of the intestine. In a patient whose intestinal damage is located further down, the biopsy may come back negative. If the endoscopy is positive the diagnosis is confirmed, but if it is negative, the diagnosis is not necessarily excluded.
Serology has been proposed as a screening measure, because the presence in the blood of IgA antibodies reactive against gluten and tissue transglutaminase is indicative of coeliac disease. Like the endoscopy, these tests are not accurate in patients who have been on a gluten-free diet for some time; they must be performed while the person is on a normal diet or within a relatively short time after eliminating gluten. A thorough workup includes four tests:
Anti-tissue Transglutaminase Antibody (tTG), IgA. This test is sometimes used alone. If this test is positive it is highly likely that the patient has celiac disease. tTG test is not reliable in children before the age of 2.
Anti-Gliadin Antibodies (AGA), IgG and IgA. These tests are often useful when testing young symptomatic children, but they are found in fewer coeliacs than Anti-tTG, and their presence does not automatically indicate coeliac disease because they are found in some other disorders. Some people have an IgA deficiency that causes a false negative test; due to this and other factors, the IgA test has a relatively high rate of false negatives.
Anti-Endomysial Antibodies (EMA), IgA. This test is being replaced by the Anti-tTG test because both tests measure the autoantibodies that cause the tissue damage associated with coeliac disease. Many physicians still order this test. This test as tTG test is also not reliable in children before the age of 2.
Anti-Reticulin Antibodies (ARA), IgA. Anti-ARA is not ordered as frequently as it once was, because it is less sensitive and less specific than the other tests. It is found in about 60% of people with coeliac disease and 25% of those with dermatitis herpetiformis.
Many doctors will not consider positive blood tests as definitive proof of coeliac disease, but will still require biopsy confirmation. A growing minority consider coeliac disease to be diagnosed where the patient has positive blood tests and shows improved symptoms after the adoption of a gluten-free diet. Because upper endoscopies are uncomfortable, expensive, and may produce false negative results, this group of doctors considers serology tests and a positive response to eliminating gluten from the diet to be sufficient for diagnosis. A small minority of doctors advocate gluten-free diets even for symptom-free patients who have not had an endoscopy but have had a positive blood test, because some confirmed coeliacs are completely symptom-free throughout their lives; in symptom-free patients, the purpose of the diet is to avoid nutritional deficiencies, osteoporosis, and intestinal lymphoma.
Other tests that may assist in the diagnosis are a full blood count, electrolytes, renal function and liver enzymes. Coagulation testing may be useful to identify deficiency of vitamin K, which predisposes patients to hemorrhage.