How do you get tested for celiac disease?
A celiac disease test determines antibodies in the blood serum that are typical for gluten intolerance. In some cases, however, celiac disease is present, although the test does not show. Then further investigations are necessary to ensure the diagnosis of celiac disease.
Celiac disease test: Antibody
If there is a suspicion of gluten intolerance, a gluten allergy test should be carried out before a food change. To do so, the doctor takes a blood test and examines it for certain immunoglobulins. These are antibodies against the transglutaminase (anti-TG) and the endomysium (EmA).
The transglutaminase is a protein (enzyme) in the intestinal mucosa, which processes the glutamine contained in the gluten. In celiac disease the body forms antibodies against the enzyme. They circulate in the blood and attack the transglutaminase, whereupon the intestinal mucosa is inflamed.
In addition, the immune system in humans with celiac disease also forms antibodies against the so-called endomysium. The endomysium is a connective tissue layer in the intestinal wall. If it is attacked, the villi of the intestinal wall will be dismantled. Therefore, The concentration of the endomysium antibodies allow conclusions as to how strongly the intestinal villi are re-formed.
The total amount of Class A antibodies (immunoglobulin A / IgA) should also be determined within the scope of the celiac disease test.
Medical practitioners divide immunoglobulins into different classes: G, A, M, D and E. The transglutaminase and endomysium antibodies active in celiac disease belong to group A.
Gluten intolerance is often accompanied by an IgA deficiency. This is problematic for the diagnosis: if the total amount of antibodies is too low, antibodies against the transglutaminase or the endomysium can not be detected or can be detected with difficulty in a blood test. Doctors call this a false-negative test result.
Celiac disease test for IgA deficiency
n another celiac test, antibodies against the gluten component gliadin are detected. This test is only useful for IgA deficiency. In the course of a first celiac diagnosis, it is not carried out as standard. The accuracy of this test is always discussed. Instead, in the case of an existing IgA deficiency, transglutaminase antibodies of the group IgG can also be determined.
In the meantime, various manufacturers offer celiac disease tests in different price ranges. The transglutaminase and endomysium antibodies, which are typical for celiac disease, can also be detected in the blood.
How to perform the celiac self-test?
A celiac self-test is comparable to a pregnancy test. However, instead of urine, a small bloodstripe is needed for the self-test. The test kit is available without prescription in pharmacies and on the Internet. It contains a lancet for the collection of a blood droplet, a small capillary tube, a test solution in a reaction vessel, a pipette and a test cassette.
For the test, test person stabs himself with the lancet into the fingers, so that a small bloodstripe swells. He takes this with a small capillary tube. This is placed in a liquid-filled reaction vessel and shaken a little. The test person then sucks the blood-liquid mixture with a pipette and places a drop on a provided field within the test cassette. After a few minutes the result can be read off with a color shift.
Is celiac self-testing useful?
Some manufacturers of the test kits advertise with an alleged almost 100% safety of the test result. However, if one considers that erroneous results are not excluded even in a professional, expensive blood test with the doctor, this claim can hardly stand up to a serious examination. For example, a celiac rapid test is susceptible to a faulty test result if there is an immunoglobulin A deficiency in the patient.
Celiac disease breath test
With a pronounced celiac disease, a large part of the intestinal villi has re-formed. This reduces the surface area of the intestine and the nutrients can enter the blood only to a limited extent (resorption disorder). In some of these digestive disorders, this also applies to the sugar molecule xylose.
Therefore, it comes with the rest of the foodstuff into the colon, where it is cleaved by bacteria. This produces hydrogen (H2), which is transported into the lung and then exhaled.
In a xylose test, the physician measures the H2 concentration in the air of a sober patient before and after administering a xylose drinking solution. An increased concentration of hydrogen indicates a resorption problem, the cause of which can be celiac disease. However, since there are other reasons for a resorption problem, it is not a specific celiac disease test.
Celiac disease test in children
If no antibodies can be measured in the celiac disease test in children (also in screening tests of risk groups), the antibody values (in contrast to adults) should be re-checked in the following intervals: in the first two years every six months, then after five and after ten years.
In some cases, a sample of the small intestine can not be used in children with suspected celiac disease. This is the case when the children suffer from symptoms of celiac disease and show typical signs of a nutritional impairment, and furthermore the following four criteria are met:
- In the celiac disease test, transglutaminase antibodies reach tenfold higher than the limit value
- Endomysium antibodies can be detected
- There is a genetic disposition for celiac disease (HLA-DQ2 and / or -DQ8)
- The discomfort subsides under gluten-free diet