Blood Test: Gliadin Antibodies

Article Translations: (Spanish)

What It Is

A gliadin antibodies test is used to help doctors diagnose celiac disease. Celiac disease is an autoimmune disorder in which the body's immune system mistakenly thinks that gluten — a protein in wheat, barley, rye, and oats — is a foreign invader. Gliadin is a portion of the protein found in gluten.

The immune system of someone who's sensitive to gliadin produces anti-gliadin antibodies (AGA) to attack the protein. The antibodies are divided into two groups:

immunoglobulin A (IgA)
immunoglobulin G (IgG)

IgA is more useful in detecting celiac disease because it's made in the small intestine, where gluten causes inflammation and irritation in sensitive people. IgG levels are less specific to celiac disease, but may still be used in diagnosing autoimmune problems, especially in people who are deficient in IgA.

Measuring the levels of both types of gliadin antibodies in the blood lets doctors assess the immune system's response to gluten.

Why It's Done

The gliadin antibody test is used to help diagnose celiac disease or monitor its treatment.

Preparation

For accurate results, a child must be on a diet that includes gluten, such as wheat-containing breads, pastas, and baked goods. The body will only produce antibodies when it's exposed to gliadin. If gliadin has been removed from your child's diet, there won't be an antibody response to measure.

On the day of the test, it may help to have your child wear a T-shirt or short-sleeved shirt to allow easier access for the technician who will be drawing the blood.

The Procedure

Only a little blood is drawn for the test. A health professional will usually draw the blood from a vein after cleaning the skin surface with antiseptic and placing an elastic band (tourniquet) around the upper arm to apply pressure and causing the veins to swell with blood. Then a needle is inserted into a vein (usually in the arm inside of the elbow or on the back of the hand) and blood is withdrawn and collected in a vial or syringe.

After the procedure, the elastic band is removed. Once the blood has been collected, the needle is removed and the area is covered with cotton or a bandage to stop the bleeding. Collecting the blood for this test will only take a few minutes.

drawing_blood

What to Expect

Collecting a blood sample is only temporarily uncomfortable and can feel like a quick pinprick. Afterward, there may be some mild bruising, which should go away in a day or so.

Getting the Results

In the lab, the blood sample usually will undergo a test called an ELISA (enzyme-linked immunosorbent assay). This involves incubating the blood on a special plate with various chemicals. By measuring the intensity of the color change that follows, doctors can tell whether gliadin antibodies are in the blood. The results are usually available within 1-2 days.

If results show the presence of gliadin antibodies, the doctor will probably do other tests, which may include a biopsy of the small intestine to look for evidence of gliadin-induced inflammation.

Risks

This test is considered a safe procedure. However, as with many medical tests, some problems can occur with having blood drawn. These include:

fainting or feeling lightheaded
hematoma (blood accumulating under the skin causing a lump or bruise)
pain associated with multiple punctures to locate a vein

Helping Your Child

Having a blood test is relatively painless. Still, many children are afraid of needles. Explaining the test in terms your child can understand might help ease some of the fear.

Allow your child to ask the technician any questions he or she might have. Tell your child to try to relax and stay still during the procedure, as tensing muscles and moving can make it harder and more painful to draw blood. It also may help if your child looks away when the needle is being inserted into the skin.