Deamidated gliadin peptide antibodies, DGP, DGP-AGA
This test looks for the level of deamidated gliadin antibodies (DMG) in your blood. Gliadin is one of the main proteins in gluten. The test is used to help find out whether you have celiac disease, an autoimmune disease.
If you have celiac disease, your immune system responds abnormally to gluten, which is mainly found in wheat, barley, and rye products. It's also found in common products such as lip balm, medicines, and vitamins. If you consume products that contain gluten, your immune system attacks and damages the tiny tubules that line the small intestine. If these villi are destroyed, you will become malnourished even if you are eating well. Complications of celiac disease include joint pain, thinning bones, anemia, seizures, and cancer.
More than 90 percent of people with untreated celiac disease have higher-than-normal levels of DMG antibodies, but very few people without the disease do.
You may need this test if you have symptoms of celiac disease. Signs and symptoms vary from person to person, but common ones include:
Stomach pain and bloating
Stools that are pale, fatty, or smell unusually bad
Canker sores in the mouth
Tingling and numbness
Anxiety or depression
Even if you don't have symptoms, your doctor may also order this test if you have iron deficiency anemia or a deficiency in folate or vitamin B12. These deficiencies may mean that your body is not absorbing enough nutrients.
Other signs and symptoms of celiac disease that might trigger this test include:
Regular migraine headaches
Low birth weight in infants
Several conditions are also more common in people with celiac disease. If you have symptoms of celiac disease and have one of these conditions, your doctor may order this test:
Type 1 diabetes or other autoimmune disorders
If you have already been diagnosed with celiac disease and are on a gluten-free diet, your doctor may have you tested from time to time to see whether your body is responding well to the new diet.
Your doctor may also order other blood tests to look for celiac disease:
IgA endomysial antibody, or IgA EMAIg
A tissue transglutaminase antibody, or IgA tTG
Complete blood count
Lipid levels, for total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides
Your doctor will likely want to confirm the diagnosis of celiac disease with a small intestine biopsy. He or she may also do a bone density scan to see whether you have bone loss as a result of the celiac disease.
Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your health care provider.
Normal results are negative. If you are a low risk for celiac disease and have a negative result, it likely means you don't have the condition. If you are at high risk for celiac disease and have a negative result, your doctor will interpret the results, based on your symptoms and medical history. He or she may do a small bowel biopsy in case it's a false-negative.
A positive test result means that it's likely you have celiac disease. Usually, your doctor will do a small bowel biopsy to confirm the diagnosis.
The test requires a blood sample, which is drawn through a needle from a vein in your arm.
Taking a blood sample with a needle carries risks that include bleeding, infection, bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight stinging sensation or pain. Afterward, the site may be slightly sore.
If you have been avoiding foods containing gluten in the weeks before your test, your antibody levels could be normal even though you have celiac disease. It's important to keep gluten in your diet before the test.
The test may not be as accurate in children younger than 5, especially in children younger than 2.
It's important to eat a normal diet, including foods that contain gluten, in the weeks leading up to your test. If you have gone off of gluten foods because you suspect celiac disease, you should go back on a gluten-rich diet for two to 12 weeks before the test.
In addition, be sure your doctor knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illicit drugs you may use.